AudioCircle
Audio/Video Gear and Systems => Open Baffle Speakers => Topic started by: matevana on 9 Jul 2012, 02:30 pm
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The Hestia OB Project
(http://www.audiocircle.com/image.php?id=64929)
Background:
I’ve spent the past few months actively auditioning drivers that might be well suited for the Hestia OB project. An emphasis was placed on auditioning several mid bass/HF driver combinations that would become the cornerstone of this project. All were reviewed in the same test baffle and listening environment. So as not to overburden anyone with a gigantic post, I will be breaking this project into several installments over the next few weeks, complete with pictures, links and other information. Please feel free to mark this thread and follow along!
Hestia OB Design Goals:
Well integrated driver selection
Shallow slope crossover w/low component count
High efficiency
Neutral vocal presentation
Small 3-way all inclusive design
Refined “no shout” voicing characteristics
Extended horizontal dispersion
Low cost (no single driver > $50 US)
Consistency; ability to replicate the design for the DIY community
At least 75% of the success rate in OB can be attributed to driver selection. In addition to choosing drivers that perform well in OB, they must also integrate properly amongst themselves. It seems that many amateur OB projects consider the former but not the later point. Selecting drivers with well mannered roll-off characteristics will minimize the component count and preserve efficiency. Drivers with relatively smooth curves will allow for less complex crossovers. And perhaps most important in OB is the actual voicing characteristics of the driver itself. This can be a factor of the cone’s material and thickness, VC former construction, the baskets ability to suppress additional reflection, and a number of generally accepted TS parameters that are conducive to OB. The fact is that many acclaimed (and often expensive) drivers typically used in conventional box designs make poor choices in OB. Conversely there are a myriad of lower priced drivers that make excellent candidates.
One of the primary design goals of the Hestia was to address vocal shout that seems to be present in many amateur and professional designs alike. For the purpose of this project, shout will be addressed primarily at the driver selection stage and secondarily in the crossover design. Many hours have been spent listening to raw drivers and driver combinations in the 1k to 5k Hz frequency range. I truly believe this one factor can make or break a design.
As if the above mentioned design goals aren’t lofty enough, cost should also be a big factor in the DIY arena. For this reason I decided that no single driver should cost more than $50 US, and where possible, even less.
From previous OB projects I have decided that I really enjoy the presentation that a well suited 10” pro sound driver provides in OB for the critical midrange segment. Unlike traditional 10” woofers, they are often voiced to provide stronger midrange up through 4-5k Hz. They also provide a full lower midrange on an open panel, where otherwise two smaller drivers might be needed. Since it will be crossed relatively low, beaming is not much of a consideration here.
I spent a few months listening to eight 10” driver candidates made up of pro sound, guitar and bass guitar drivers One had an aluminum cone, another two were made of hemp and fiber and the rest were paper or paper blends. One driver had an alnico magnet, two had smallish neo magnets and the rest were ceramic. One driver even had an all paper former; the rest were poly. Most were in the .5 to .9 Qts range and all had an efficiency of at least 92dB at 1w/1m.
Based on a variety of listening tests, two drivers emerged at the top of the list, but one was cut due to cost (considering the mantra of no single driver > $50). The winner in this impromptu shoot-out was the MCM audio select 10” pro sound cast frame driver, # 55-2981. Every time I considered this driver I could not believe how ridiculously low priced this driver is positioned. It is basically a very well made cast frame driver with a 2”voice coil, a treated paper cone and a very useable xmax of 6.5mm and Qts of .54.with an average sensitivity of 93dB. It is often seen on sale by the manufacturer for around $25 US. Truly unbelievable. More important, it has a very nice low mid presentation with a rapidly descending roll off above 2k and no shout when crossed properly. A perfect choice for the Hestia project.
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2981-/55-2981
Next installment, conquering the high-end.
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Baffle dimensions showing Right Panel (Left is mirror image)
(http://www.audiocircle.com/image.php?id=64841)
MCM Audio Select, Cast Frame 10" Pro Sound Driver, #55-2981 < $30 US!
(http://www.audiocircle.com/image.php?id=64842)
MCM Audio Select, Manufacturer's Stated Frequency Response & Impedance Rise
(http://www.audiocircle.com/image.php?id=64843)
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Can't wait to read more.
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Can't wait to read more.
Exactly - this looks like a fun project. :thumb: Eager to hear about x-over points, total sensitivity, etc.
Might be a great match for my Scott 222c
Thanks for sharing
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what a timing...about to create a 3 way OB and here comes another contender....cant wait....
V
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I spent a few months listening to eight 10” driver candidates made up of pro sound, guitar and bass guitar drivers...
Based on a variety of listening tests, two drivers emerged at the top of the list, but one was cut due to cost (considering the mantra of no single driver > $50). The winner in this impromptu shoot-out was the MCM audio select 10” pro sound cast frame driver, # 55-2981.
If you don't mind sharing, what where the other seven? Also, were you listening to all of them full-range?
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Wow, for the price of one Beta 12LTA I can buy two MCM's. I have the Betas and love them but are the MCMs as good?
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If you don't mind sharing, what where the other seven? Also, were you listening to all of them full-range?
Sure thing. I have access to a bunch of Eminence drivers, many originally intended for guitar or bass applications. Remember that in the context of this project, they are being used as mid/upper bass drivers. Many of those tested had limited excursion. I was mostly interested in experimenting with different voicings, cone materials, alnico magnets, etc. They were all fairly efficient but many were far from flat in their response.
MCM Audio Select model 55-2981 (ultimately selected for this project)
MCM Audio Select model 55-2961 (not bad but for the small difference in price, the above was a better performer).
Eminence Lil' Buddy (very nice sounding driver, hemp cone, extremely flat, very limited excursion, a little too pricey for this project)
Eminence Copperhead
Eminence Legend 1028k (alnico)
Eminence Basslite CA2010 (aluminum cone)
Eminence Basslite CH2010
Eminence Legend BP102
I previously tested a 10" Tone Tubby hemp cone driver, which initially peaked my interest in using these types of drivers as the "heart" of a 3-way OB. The Tone Tubby was a little more lively than the Eminence Lil Buddy and not nearly as flat. One day I plan to look at a project with the Eminence Lil' Buddy; I was particularly impressed with its flat response in my area of interest and it's nice, laid back appearance. It's Qts is perfect for OB but it's xmax is extremely limited so it would need to be filtered on it's low end as well.
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Wow, for the price of one Beta 12LTA I can buy two MCM's. I have the Betas and love them but are the MCMs as good?
I think it depends on where you plan to cross them. The Beta 12LTA (with it's whizzer cone) is intended to play fairly high. Some people prefer to cross larger diameter drivers low. In my project, the MCM starts it's roll-off at around 1400Hz. With the right combination of drivers and crossover points, it has a very elegant lower mid presentation. Last night I was listening to a Strunz & Farah CD where they were trading high speed acoustic guitar arpeggios. It just sounded right, with the proper weight, attack and decay. I am very happy with it.
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Perhaps my aging eyes missed it, but are you going passive Xover or active? One amp, or multi?
Looks to be an interesting project, thanks for sharing!
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Perhaps my aging eyes missed it, but are you going passive Xover or active? One amp, or multi?
Looks to be an interesting project, thanks for sharing!
Nope, you didn't miss it. :D In a nut shell the Hestia is a 3-way dipole hybrid with two different 10" drivers and a 3/4" dome. It is crossed passively between the tweeter and mid/upper bass driver with a 1400 Hz LR-2 low pass and an 1800 Hz LR-2 high pass (I will post the schematic shortly). Bass duties are handled by the 2nd 10" woofer and crossed at 90 Hz LR-4 with a Bash style class-D plate amp. Based on a quick mic session, the average efficiency of the mid/high side is around 91dB @ 1w/1m. The system operates in mono from 90Hz down and is true dipole up through around 1800 Hz where it starts it's transition to a cardoid pattern.
One of the design goals was easy and consistent replication, so the passive crossover can be built on a readily available Dayton pre etched PC board. It's just a matter of dropping in two coils, two caps and 8 solder points. The driver integration process included level assessment so there is no need for an additional l-pad on the tweeter side.
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Tweeter selection was almost as daunting. I know from previous use that I really enjoy the neutral sound of the Usher 9950-20. But in keeping with the design goal of < $50 per driver, I set out to test a bunch of lower cost drivers that exhibited similar neutrality with a nice airy top end. In a two week period I borrowed as many tweeters as I could get my hands on. One aspect that became apparent was the enhanced dispersion characteristics of a ¾ dome vs. a one inch or larger diameter. But in a world of trade-offs, I wondered if it would be possible to meet the mid driver at a relatively low frequency w/o high distortion. In short, the answer was maybe… at least in theory.
I was unable to get my hands on the newest series of neo magnet Vifa/Peerless ¾ dome tweeters that have a surprisingly low Fs for their size. I did have an XT19 ring modulator style driver, along with a classic (and still available) D19TD-05 poly dome. I used the Usher as my benchmark and compared it’s neutral sound to a few Morel models, the above mentioned Vifa’s and several small Dayton neo domes and one Hi-Vi model as well. I started by crossing each of the drivers at 2k Hz LR-2 (not too taxing) and just listened to them. It’s amazing what you can hear when you isolate a driver before attempting integration. I listened to a bunch of cymbal and click tracks from a drumworks test CD, paying particular attention to the air the tweeter produces. Right off the bat about half of the test samples seemed to produce a “tizzy” quality to their top end. The Morel drivers were nice and a little on the warm side but had the poorest horizontal dispersion of the group, possibly due to their 1 1/8” diameter dome. The Dayton drivers were nice and small but seemed to suffer from consistency among the sampled pairs. In two cases, the overall clarity was questionable; one was a 5/8” dome and integration would likely have been problematic anyway.
The Vifa XT19 was an interesting bird. It didn’t measure too well with a simple LR-2 alignment, but I understood from reading about this driver that it would likely need more attention. The best results came with a 3rd order alignment using a cap on either side of the shunted coil. It did sound nice, but the more complex x/o might present phase integration problems with the intended lower order x/o of the mid woofer. The additional parts would also add cost to the project. On the plus side, it did have excellent horizontal dispersion at 30 and even 45 degrees off axis.
Interestingly enough, the driver that I preferred the most was the Vifa D19TD-05. It’s a classic style poly dome that Vifa OEM’d for use in many boutique shop branded mini monitors. It has excellent dispersion properties and next to the Usher, shared many of the same characteristics at a much lower cost. The pair that I have are made in Denmark. Vifa/Peerless currently produces this driver in Asia and many of the reviews have been favorable regarding the current facility’s ability to reproduce a faithful copy of the original. This driver will likely be produced for the long haul since it’s a drop-in replacement for so many mini-monitor style speakers. It also plays loud and clear and seems to handle a fair amount of power. Best of all, it currently retails for around $16 US.
On the down side it has a fairly high Fs, which might otherwise be problematic for this particular project. Based on my listening impression and the bargain basement cost of this nice tweeter, I wanted to see if there was a way to make it work.
Next up, passive crossover design and combating driver “shout”
The Tried & True $16 Vifa D19TD-05-08
(http://www.audiocircle.com/image.php?id=64860)
(http://www.audiocircle.com/image.php?id=64861)
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A few pics of the prototype:
(http://www.audiocircle.com/image.php?id=64930)
(http://www.audiocircle.com/image.php?id=64931)
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The inductors are Jantzen 18 AWG air core and the Caps are Dayton Audio Polypropylene. I use the Dayton pre etched 2-way PC board number 260-130 which makes a nice finished product. I typically mount them on the baffle back with rubber washers.
L1 = 1.80 mh 18 AWG
C1 = 7.5 uf
L2 = 1.40 mh 18 AWG
C2 = 5.6 uf
(http://www.audiocircle.com/image.php?id=64935)
(http://www.audiocircle.com/image.php?id=64936)
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You will probably want to change the orientation of one of your air coils to reduce inductive coupling.
google speaker crossover inductor orientation the first few hits will explain the issues.
Danny also has a good crossover primer here
http://www.audiocircle.com/index.php?topic=83325.0
Shawn
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You will probably want to change the orientation of one of your air coils to reduce inductive coupling.
Shawn
Yes, the coils are just attached with a strip of velcro for now to test the prototype. The finished board will have the smaller inductor flipped on its side and zip tied to the board.
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I'm just curious if anyone has ever either measured or heard adverse effects from inductors not all positioned at right angles in four dimensions.
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The bass driver:
The new Dayton line of pro sound drivers were selected for this project to handle bass duties, in particular the model PA255-8 10” Pro Sound woofer. Essentially there were three factors that went into this decision, namely (1) a high sensitivity of 95dB; (2) an Fs in the mid 40’s which is about 10 Hz or more lower than most 10” pro sound drivers, coupled with favorable Qts, xmax and MMS measurements; and (3) low cost ($43 US).
During development I routinely alternated the positions/duties of the Dayton with the MCM driver and came to this conclusion. I definitely prefer the MCM driver for mid duties, in fact it is the cornerstone of this project with its accurate and unassuming presentation, beating out a myriad of other tested drivers. That being said, the Dayton driver only offered a slight advantage in bass duties over the MCM in its ability to play slightly lower, slightly louder and handle slightly more power. Could the project be built using two MCM drivers at a lower cost? Absolutely… just remember that the cut-out for the MCM is around 1/8” larger. Still though the Dayton offers slight advantages in the bass position and stays within my goal of sub $50. It also comes with rear gaskets that help dampen unwanted resonances down low.
Next up: Pulling it all together
(http://www.audiocircle.com/image.php?id=64952)
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Did you consider an H-frame design for the bass drivers?
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Did you consider an H-frame design for the bass drivers?
Fair question. Here's my philosophy on H and U Frames as it relates to this project, although some may disagree :D
Martin King clearly demonstrates that the same driver will go lower in both an H and U alignment, at the possible expense of some SPLs. While I won't suggest (as others have) that the additional structure starts to take on sonic characteristics of a "box", I will say that I really enjoy the low profile, small footprint appearance of a flat panel system. In a much more comprehensive system like Orion, the speakers can be used at very high SPLs and produce ample bass. If anyone tried to build the Hestia project (with it's one 10" bass driver, panel mounted) I suspect they would be satisfied with the low output up to moderate levels, and perhaps employ a separate sub beyond that. I believe that would STILL be the case if these same drivers were used in an H or U. Hope that makes some sense.
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It is interesting that you don't have a second tweeter facing backwards to get dipole high frequencies. What are the tradeoffs involved in using dipole bass and mids but "monopole" highs?
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It is interesting that you don't have a second tweeter facing backwards to get dipole high frequencies. What are the tradeoffs involved in using dipole bass and mids but "monopole" highs?
A "true" dipole flat panel may either use a cone type high frequency driver, or a planar driver with it's back exposed, or a 2nd dome facing rearward with it's polarity reversed as you mention. IMO this really comes down to a preference. A true dipole may sound slightly more diffuse with an emphasis on creating natural reverberations. This can offer a pleasing effect, but may also detract from the sound stage due to high frequency directionality. In more extreme cases it is possible to smear the stereo image, but this may be more a factor of the room. I have found that I really love dipole bass and mids, but am less decisive when it comes to high frequencies. I prefer a more intact stereo image that can otherwise be softened by the presence of additional rear wall reflections, etc... but still, many prefer the opposite.
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Ideally you'd want both a waveguide and an open back on the tweeter, to match the dispersion characteristics of the mids and bass. But highs seem to be less critical to do full OB, especially above 3k or so.
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How do they sound...?
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How do they sound...?
They sound great... better than a pair of OB's I own at 3 times the cost. At $85 per side (all 3 drivers) they are also an amazing value. Their strength lies in the fact that all 3 drivers integrate well, and are well suited for OB. The crossover targets a roll back in an area where the mid and tweeter intersect, and greatly reduces "shout" associated with many systems. This slight dip in the response makes the Hestia sound refined, but not weak in the critical mid range area. The 10" mid has a great power curve and is surprisingly fast and articulate despite it's size. Acoustic instruments in particular are reproduced with proper weight and proportion. They image better than my other OB pair, which are dipole throughout their range.
I am especially pleased with the $16 Vifa D19's, which have been tasked to play below their comfort zone. At moderate levels, I can detect no audible strain in their sound. Oddly enough, this was not the case with other HF drivers I tested, many with a lower Fs. All of the drivers have a fairly polite roll off, so the x/o component count can be kept low. I can also detect no obvious phase issues with the x/o; the polarity of all 3 drivers should be maintained (not inverted) despite the existence of two Linkwitz Riley pairs.
While they excel in reproducing quality recordings, they are also comfortable with more modern music, which are typically recorded with a lot of compression. This is not the case with my former dipole pair, which were almost unbearable with certain types of recordings.
Lastly, I also happen to think they are pretty handsome. :thumb: Their sleek footprint is minimalist and they they are unassuming in a living room environment. When you compare them to an H or U Frame, they have a more modern and clean look. For my prototype I built one side in a beech finish and the other in ebony... not sure which I prefer but both look nice.
I am really hoping someone chooses to build them, as I would certainly appreciate the additional feedback! I would be glad to assist where possible.
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Lastly, I also happen to think they are pretty handsome. Their sleek footprint is minimal and they they are very unassuming in a living room environment. When you compare them to an H or U Frame, they have a more modern and uncluttered look. For my prototype I built one side in a beech finish and the other in ebony... not sure which I prefer but both look nice.
Matevana,
Great job on your design...I do think in their simpleness, they are sleek/handsome! I am yet to own, or even heard an OB speaker, but am interested. How do you suppose the sound would be affected if the flat/square top of the baffle was modified to instead be somewhat rounded/arched, raising the overall height by an inch or two?
Pete
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How do you suppose the sound would be affected if the flat/square top of the baffle was modified to instead be somewhat rounded/arched, raising the overall height by an inch or two?
Pete
Hi Pete,
You should be fine. Try to keep the baffle width as close to 15" as possible. An increase in baffle height of a few inches should have little or no effect... I would keep the drivers in the same position as measured from the base. A rounded "tombstone" style baffle should look nice! Good idea.
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While they excel in reproducing quality recordings, they are also comfortable with more modern music, typically recorded with a lot of compression. This is not the case with my former dipole pair, which was almost unbearable with certain types of recordings.
That is so important. When music tastes range from 60's folk and world, garage rock, 70's folk, 90's hip hop, modern rock and remasters.
I'd be interested in building a pair this fall. My summer is a little too busy.
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I'd be interested in building a pair this fall. My summer is a little too busy.
Sounds good! Keep an eye out for coupon codes from MCM. On occasion they offer 10% or 15% off, and sometimes free shipping. I've seen the 10" mids as low as $23, which is truly amazing, considering they are very well made, with nice cast frame baskets, spring loaded gold terminals, and are very efficient.
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Hi Pete,
Try to keep the baffle width as close to 15" as possible. An increase in baffle height of a few inches should have little or no effect... I would keep the drivers in the same position as measured from the base. A rounded "tombstone" style baffle should look nice! Good idea.
I think the "tombstone" style baffle would be "killer", and wouldn't deviate from the nice, simple design.
Your design goal of keeping the drivers <$50 each (WELL below <$50 each) certainly appeals to the "thrifty" side of me. I'm with the astronaut...need to finish some things up before I can take on another project.
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Neat project. How bout some rear views?
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Neat project. How bout some rear views?
Hey Poultry,
Here's the butt shot you requested :thumb:
(http://www.audiocircle.com/image.php?id=63736)
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nice butt
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Here's a few pics of the finished pair w/matching Audio Cabinet.
(http://www.audiocircle.com/image.php?id=65395)
(http://www.audiocircle.com/image.php?id=65396)
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Great effort and no doubt great results. You should be proud. :thumb:
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any thought about a passive version of this? I have a pair of alpha 10's gathering dust. would need new crossover pair. just finished a new 3-way, OK but no bass, as expected. there's room for me to cut in a 10" in place of my current mid. would look way cool!
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any thought about a passive version of this? I have a pair of alpha 10's gathering dust. would need new crossover pair. just finished a new 3-way, OK but no bass, as expected. there's room for me to cut in a 10" in place of my current mid. would look way cool!
An all passive version using the current drivers would be difficult since the MCM mid woofer is so efficient, at around 94dB @ 1w/1m. As Martin King illustrates on his website, you ideally want your bass driver to start out around 10dB more efficient than other drivers in an all passive design. This would ensure an adequate level match once the crossover is applied. You will not likely find a bass driver that exhibits 104dB efficiency @ 1w/1m in it's requested range of < 90Hz, including your Alphas. This is why I use a separate plate amp; where a proper level match can be achieved w/o taxing your main amplifier.
A decent quality plate amp for this project would be something like a Bash 300, or a Yung 300. Both are cool running class D amplifiers, and periodically go on sale around $100. You basically set them up once and you're done.
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my knowledge of plate amps is nil. more research required. thanks.
can you supply a finished wiring diagram, including the receiver, or point me in that direction? thanks again. :o
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Since you're already b-amping, have you considered tri-amping with a separate amp and a simple cap filter for the tweeters and allowing the MCMs to run full range?
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Since you're already b-amping, have you considered tri-amping with a separate amp and a simple cap filter for the tweeters and allowing the MCMs to run full range?
I have not considered tri-amping, only because I feel the cost/benefit isn't quite there with this design. I honestly could not be happier with the mid/high SQ, considering the nominal cost of the drivers.
For the money, I would rather invest in a 2nd plate amplifier and run stereo from 90Hz down. For me that would be the next logical upgrade. In doing so I might raise the lowpass to around 120 Hz depending on the result.
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my knowledge of plate amps is nil. more research required. thanks.
can you supply a finished wiring diagram, including the receiver, or point me in that direction? thanks again. :o
Take a look at this link for a nice plate amp at a reasonable cost. Today PE is running a 'deal of the day' special for $99.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=301-510
I simply run the left/right line out from my integrated amplifier (receiver) to the left/right input of the plate amp. The plate amp comes on automatically when it senses an input signal, and turns off about 15 minutes after the last signal is presented. With this model you have control over gain (level match), crossover (frequency match) as well as a full variable phase control (0 through 180 degrees) to more seamlessly integrate the phase/delay relationship between the plate amp and main amp. It also uses a class D switching power supply mode, which essentially produces lots of power with little heat, in a small package.
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I use two of these Daytons amps which have built -in crossovers to drive my H-frame Alphas. They can be daisy chained ( mono or stereo ) and each has a volume control. I bought them when they were on sale for $120 each. They were formerly sold by Emotiva.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-812&FTR=apa%20amplifier
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Hmmmmm. having a few thoughts.......I own but no longer use a sony subwoofer. If I remove that dual voice coil speaker, can I wire the rest in to my existing 3-way setup? or is that loony? it has controls for cut-off freq, phase and level. thanks for any help, and sorry if thread appears hi-jacked.
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I use two of these Daytons amps which have built -in crossovers to drive my H-frame Alphas. They can be daisy chained ( mono or stereo ) and each has a volume control. I bought them when they were on sale for $120 each. They were formerly sold by Emotiva.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-812&FTR=apa%20amplifier
Yeah, I like those. Very useful in a lot of applications and they have nice 18dB/oct low pass filters.
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Hmmmmm. having a few thoughts.......I own but no longer use a sony subwoofer. If I remove that dual voice coil speaker, can I wire the rest in to my existing 3-way setup? or is that loony? it has controls for cut-off freq, phase and level. thanks for any help, and sorry if thread appears hi-jacked.
You can try, and if you're not happy, go out and buy a different plate amp. :)
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Some experimentation on low frequency driver integration and drive levels:
LF Driver height:
I have definitely found that placing the woofer as close to the floor as possible is an advantage when dealing with boundary effects and floor bounce. As demonstrated decades ago by the Allison model one speaker, its advantageous to keep these drivers low. This helps push any resulting negative cancellation from bounce above the critical 100 to 300 Hz range, which plague many speaker designs. Experiencing "suck-out" in this range can greatly reduce realism. If you do have residual bounce effects from your room, it's best to push them above this range.
LF Crossover Settings:
While every design is different, I personally try to keep signals above 90Hz away from the LF driver. Most of my designs use a single plate amp for LF signals which sum the front left & right output into a monaural signal. If you cross at higher frequencies you are likely to start experiencing a degradation of the stereo image, as the location of this information starts to become more detectable by the human ear.
LFE Output:
I try never to use the LFE output from a receiver. It's important to have the flexibility from a continuously variable crossover when integrating drivers. The course settings from most receivers will simply not cut it. I have found that differences as small as 10Hz can make a difference when attempting to seamlessly integrate drivers.
Pre Out or Subwoofer Line Out:
Oddly enough, it seems that many amps used to drive LF speakers are not driven sufficiently by the line out coming from the receiver. The level is oftentimes too low as many receiver designs err on the side of caution in determining output level with a host of possible manufacturers equipment (less of a customer support issue when the signal is set too low than too high).
It's amazing to hear the sound quality difference between signals from a receiver's line out vs. splitting the source and sending that directly to your LF plate amp. If you'd like to try an inexpensive test, get an RCA splitter like the one pictured below (y-cables are not always the best choice here) and compare that to the signal quality from your receiver's line out. In most cases the signal level will be a better match and will drive the amp with more authority, and slightly lower distortion (and heat) due to the ability to now run the amp at lower levels. You will need to either preset the plate amps level or use the volume control on your source unit (CD player, if equipped) as a master volume control.
(http://www.audiocircle.com/image.php?id=65743)
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I also like splitting the source.
In my case I take the analogue out put from the CDP and send it to my integrated tube amp which drives the full range mains. Then I take the digital output from the same CDP and send it to a Denon AVR which drives the bass woofers through a 80hz low pass. I think I paid $35 for the non-HDMI AVR and it has plenty of power for my bass woofers in two channel mode and is way cheaper than plate amps. It's also nice to have a remote to control the bass output.
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I also like splitting the source.
In my case I take the analogue out put from the CDP and send it to my integrated tube amp which drives the full range mains. Then I take the digital output from the same CDP and send it to a Denon AVR which drives the bass woofers through a 80hz low pass.
Great point Poultry using the digital output as a 2nd source for your AVR. This wont work for plate amps obviously, but for anyone like yourself who uses an AVR as their LF amp, you will certainly benefit from this as well. It must also be nice to have arm chair control of the sub's levels! What are you using for an integrated amp?
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I have two integrated amps, a Miniwatt S1 and a Dared 2a3c. I use these interchangeably to drive the main OB full rangers while using an AV receiver to drive the bass Alphas. You can't beat garage sale AV receivers for cheap watts and since HDMI came into vogue there are tons of cast off non-HDMI AVRs on the used market.
On another set of OB Beta/Alpha H-frames I use a Bottlehead 2a3 amp/preamp on the Betas/tweeters. In that system I drive the Alphas with two Dayton APA 150's ( with built-in crossovers ) but I can't say the Alphas perform any better than with an AV receiver and two low pass filters.
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I wish I could hear your system. The only real pitfall about having OB as a hobby, is their lack of popularity and the associated difficulty in comparing designs in person :o
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And I yours.
While there's little opportunity to hear other's systems it's safe to say that most of us who have experienced OB are convinced of it's goodness. It has spoiled me to no end.
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Matevana, do you have a complete build thread and x-over diag. for this. I think this
might be my first OB project, I already have the tweeters and like everything else I
have read in the thread it seems to be incredible bang for buck.
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Matevana, do you have a complete build thread and x-over diag. for this. I think this
might be my first OB project, I already have the tweeters and like everything else I
have read in the thread it seems to be incredible bang for buck.
Hi Squidspeak,
Post #13 shows the capacitor and inductor values, the wiring schematic and the finished crossover. It uses a very traditional Linkwitz-Riley 2nd order electrical wiring scheme. You can even buy pre etched boards to make the finished design look a bit neater.
While the LR-2 wiring scheme is standard, the piece that's a bit unusual lies in the component value selection. Not only is there no significant overlap between the tweeter and midbass, but by design, there is a small deficit between the two, producing a very slight dip in the frequency range normally associated with loudspeaker "shout". This helps give the Hestia it's characteristic sound, and IMO makes for hours of non-fatiguing listening possible. Unlike some large woofer/small FR driver designs, the midrange is NOT lacking and comes across as very natural with the proper weight and authority.
I had the luxury of being able to design-on-the-fly using a 3 way active crossover at the same 12dB slope, which was a great help in listening to driver interaction and understanding the outer limits of each driver. Once the x/o points and levels were scrutinized using the active set-up, I swapped in the passive components and remeasured (and swapped components again) until the new curve more or less matched the original. My take-away from this exercise was that while many drivers operate properly within their stated response range, huge performance gains can be derived by avoiding the the fringes of this range.
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Just curious - why did you switch to passive? Why not just keep the active crossover in place?
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Matevana, thank's for the response. This will be my first OB project and
what sold me was I bought those tweeters from P/E when on closeout
and they would not work in my project, so I've been trying to find a use
or home for them. Also wanted to try a OB design but wasn't sure which
one. Anyway do you feel this design would benefit from going with stereo
on the bottom(2 plate amp's)?
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Just curious - why did you switch to passive? Why not just keep the active crossover in place?
The design goals for the project included: low cost; all inclusive design; easily reproducible results. An all active 3-way design would likely be out of the price range for many who might otherwise be tempted to build this project. It would also be subject to improper adjustment for those not familiar with the desired outcome.
As it stands, the Hestia will sound phenomenal with less than $200 in amplification, namely a small tripath amp for the mids/highs and a decent plate amplifier for the lows. It is also sensitive enough to be run with small integrated amps, SETs, etc. That being said, anyone who wishes to convert the project to three amps and a 3-way x/o will likely see increases in performance; just not sure it's the best bang-for-the-buck when the project title reads "ambitious low cost 3-way OB design". :D
One more comment regarding sound quality with active designs. I have used crossovers from DBX and Ashly with good results. These were typically good quality analog designs with fairly high signal-to-noise characteristics and dynamic range. I have also experimented with digital x/o's from Berringer and MiniDSP. While many might disagree, I typically experienced a degradation in overall SQ with these digital versions, albeit the adjustment was very precise.
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Matavena, I saw in another thread you suggested the OP just use the passive
top with an existing sub. Would there be much to gain "budget aside" by going
with larger bass drivers and 2 plate amps in stereo?
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I personally like the sound of OB bass (for music). The person in the other thread had an existing vented box he wanted to use in conjunction with an OB top. In his case, the Hestia minus the the LF driver would be fairly easy to integrate.
Personally I wouldn't change anything about the design. It is very balanced at moderate SPL's and the bass is not lacking. I would use a decent plate amp as lesser amps might have trouble keeping up. With the x/o set at around 90 Hz, very little would be gained by using a 2nd plate amp and running the sides in stereo. Certainly something you could try later as an upgrade, but I believe you will be very happy with mono bass as intended.
For amps I highly recommend either the Yung 300W with boost @ 30Hz, the O-Audio Bash 300 or the Dayton Bash 300, in that order. Other amps that I had on hand did not sound nearly as good. When they go on sale, you can get any of the three for right around $100. I have the Yung driving my Hestia right now, and it runs cool even after many hours of use. For the top I alternate between a NAD integrated amp and a Topping Tripath chip amp, and still cant decide which one I prefer. Both sound excellent with the design.
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I personally like the sound of OB bass (for music). The person in the other thread had an existing vented box he wanted to use in conjunction with an OB top. In his case, the Hestia minus the the LF driver would be fairly easy to integrate.
Personally I wouldn't change anything about the design. It is very balanced at moderate SPL's and the bass is not lacking. I would use a decent plate amp as lesser amps might have trouble keeping up. With the x/o set at around 90 Hz, very little would be gained by using a 2nd plate amp and running the sides in stereo. Certainly something you could try later as an upgrade, but I believe you will be very happy with mono bass as intended.
For amps I highly recommend either the Yung 300W with boost @ 30Hz, the O-Audio Bash 300 or the Dayton Bash 300, in that order. Other amps that I had on hand did not sound nearly as good. When they go on sale, you can get any of the three for right around $100. I have the Yung driving my Hestia right now, and it runs cool even after many hours of use. For the top I alternate between a NAD integrated amp and a Topping Tripath chip amp, and still cant decide which one I prefer. Both sound excellent with the design.
Matavena, again thanks for the response/opinion. I also want to keep it OB
bass, but I would like to use the Dayton PA310 for the bass duties and either go with
the Yung 500W mono or 2 300w stereo on the bottom. Is there any issues with the
X-over point going mono with 2 8ohms vs. stereo with individual 8ohm drivers. I just
want to kick it up a notch and still think it would be a budget build. Let me know your
opinion. I'll call it "Hestia Grand" LOL Thanks SQUIDSPEAK
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Matavena, again thanks for the response/opinion. I also want to keep it OB
bass, but I would like to use the Dayton PA310 for the bass duties and either go with
the Yung 500W mono or 2 300w stereo on the bottom. Is there any issues with the
X-over point going mono with 2 8ohms vs. stereo with individual 8ohm drivers. I just
want to kick it up a notch and still think it would be a budget build. Let me know your
opinion. I'll call it "Hestia Grand" LOL Thanks SQUIDSPEAK
Hey Squid,
The Hestia Grand? I think she will like that!
No problems with the plate amps concerning crossover points, as the active x/o is independent of the impedance load the amp sees. What's not independent however is the amount of power the amp will produce at either 4 or 8 ohms. A 500 watt amp may produce 500 watts @ 4 ohms but may only produce a little over 250 watts @ 8 ohms. Therefore two separate amps at 8 ohms per side, may not "see" much more power than two 8 ohm drivers wired in parallel to one amp (4 ohms total), if that makes any sense?
You may want to give some thought to the baffle dimensions with the PA310. The PA310 (a 12" bass driver) is larger and will require more real estate to address dipole cancellation. The 15" wide baffle may not work in your case... you may need to look at an 18-20" width instead which may also negatively impact the speakers imagining characteristics up top. The 12" drivers Fs is only 2 Hz less than the 10", so you will likely not notice any deeper bass, although it will move a larger slug of air. It also has a higher MMS rating which will likely result in more baffle noise (vibration).
I would encourage you to experiment with the design. Just wanted to point out a few things so you don't wind up paying more and getting less.
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Hey Squid,
The Hestia Grand? I think she will like that!
No problems with the plate amps concerning crossover points, as the active x/o is independent of the impedance load the amp sees. What's not independent however is the amount of power the amp will produce at either 4 or 8 ohms. A 500 watt amp may produce 500 watts @ 4 ohms but may only produce a little over 250 watts @ 8 ohms. Therefore two separate amps at 8 ohms per side, may not "see" much more power than two 8 ohm drivers wired in parallel to one amp (4 ohms total), if that makes any sense?
You may want to give some thought to the baffle dimensions with the PA310. The PA310 (a 12" bass driver) is larger and will require more real estate to address dipole cancellation. The 15" wide baffle may not work in your case... you may need to look at an 18-20" width instead which may also negatively impact the speakers imagining characteristics up top. The 12" drivers Fs is only 2 Hz less than the 10", so you will likely not notice any deeper bass, although it will move a larger slug of air. It also has a higher MMS rating which will likely result in more baffle noise (vibration).
I would encourage you to experiment with the design. Just wanted to point out a few things so you don't wind up paying more and getting less.
Well what I was considering was a tapered baffle and the top part would mantain your exact layout,the bottom would taper just enough to fit the 12" woofer.
I appreciate your opinion and don't want to mess with a great design already just
asking if for a little mo $$ could I get a little MO output on the bottom, Thanks Mike
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I like the idea of a tapered baffle if you are considering a 12" LF driver. Also, Have you considered two 10's as an option? This would allow you to keep the same baffle width and raise the mid/tweeter pair to a more normal seated height. I would be tempted to use all MCM drivers in that case, taking advantage of the quantity pricing on 4 or more. I just built a 2nd Hestia for someone else using the MCM driver in lieu of the Dayton. They measure extremely close, to the point where it's hard to justify the difference in cost. Also remember to look for promo codes. These will often save you 10-15 percent and sometimes free shipping.
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I very much like your design and appreciate your design philosophy. I plan to build a pair. I read another thread where you responded to someone who wanted a top end to go with his subs. You recommended the top end of the Hestia. Another poster recommended using the SEOS waveguide and Denovo DNA-360 CD with a "pro 12 inch woofer". I have the SEOS and Denovo and have been looking for weeks for an OB design incorporating them or similar parts. I understand how the bottom end of the Hestia could fairly easily be substituted but could the Vifa tweeter be replaced with the SEOS waveguide and Denovo CD without totally redesigning the project? The DNA-360 is SPL: 108db 1W/1m and the crossover is minimum 1000hz. It is similar to the B&C DE-250. I could provide more info but since this is my first post I probably shouldn't be touting other sites.
In any case I will be buying the Vifas when PE has them back in stock and buy three pairs of the very affordable MCMs to lift the tweeter and mid a little higher off the floor. Thanks for a very interesting plan.
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I very much like your design and appreciate your design philosophy. I plan to build a pair. I read another thread where you responded to someone who wanted a top end to go with his subs. You recommended the top end of the Hestia. Another poster recommended using the SEOS waveguide and Denovo DNA-360 CD with a "pro 12 inch woofer". I have the SEOS and Denovo and have been looking for weeks for an OB design incorporating them or similar parts. I understand how the bottom end of the Hestia could fairly easily be substituted but could the Vifa tweeter be replaced with the SEOS waveguide and Denovo CD without totally redesigning the project? The DNA-360 is SPL: 108db 1W/1m and the crossover is minimum 1000hz. It is similar to the B&C DE-250. I could provide more info but since this is my first post I probably shouldn't be touting other sites.
In any case I will be buying the Vifas when PE has them back in stock and buy three pairs of the very affordable MCMs to lift the tweeter and mid a little higher off the floor. Thanks for a very interesting plan.
Hi Peter,
A few things come to mind, the first of which is level matching the CD to the MCM mid. Assuming you are staying with one mid driver, you should expect to fabricate an L-pad with about 20dB of attenuation. You will want to get down to around 88dB @ 1w/1m, slightly higher if you plan to use more than one mid. The crossover point and slope in the original schematic should not be a problem for the Denovo.
Can you provide some information on the SEOS waveguide? Depending on the driver, you sometimes have to EQ back to flat once coupled to the WG, or you may wind up with a bit of a peak somewhere to deal with. I'm assuming others have used this combination in other projects, so that is probably already addressed (if it's even an issue). Off axis response may also be different as a result of the guide. Sounds like an interesting project. Please keep me informed.
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Thanks for your comments. I think I'll start with a Hestia build first and after some quality listening move on to some experimenting with the Denovo DNA-360 CD and SEOS waveguide. I thought of using two pairs of the MCMs for bass duties. They are so inexpensive. Do you think they would be more beneficial in the midrange?
More info on the CD and SEOS can be found at http://www.avsforum.com/t/1291022/hey-guys-we-need-a-little-rallying-here and also http://www.diysoundgroup.com/. While the focus of this group is building boxes I did find this link http://www.aespeakers.com/phpbb2/viewtopic.php?f=14&p=13897#p13842. I think the LO15 has been replaced by the AE Dipole 15 http://www.aespeakers.com/drivers.php?driver_id=32. The 15" version has an SPL of 1WSpl: 90.1dB. I believe the Hawthorne Audio Sterling Silver Iris OB 15" Coaxial Unit uses a Radian CD. All of which is to say that I think some are building OBs with waveguides and CDs. I take your point that there would need to be quite a bit of attenuation.
First things first. I'll build the Hestia and even though going into the CD/waveguide realm is probably way past my abilities I might give it a try. I wonder if the controlled directivity of the waveguide might not be a good complement to the OB concept. I'm sure I'll have a few questions about the Hestia build in the meantime.
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Completely agree with starting with the Hestia build, as the design is fairly easy to replicate. I think you will like it as-is. Many of the concepts you mention may in fact enhance the design. The Neo Note as an example, makes use of two lower-mids, so two MCM drivers would not be out of the question, but due to the 10" diameter and high sensitivity, probably less desirable. At a minimum it would change the design, and require tinkering with crossover points, levels, etc. (and not a bad project once the design is built). Remember that one of the primary Hestia design goals was a well balanced, no shout design. A 2nd mid driver would surely alter the sound characteristics, for better or for worse.
I do believe there is much to be said about wave guides in dipoles, as a natural compliment to their radiation pattern. I personally would experiment with high quality silk dome tweeters in waveguides, as opposed to CD's. You dont need the SPL's in this configuration and the curves are usually much smoother. You may even look at a small (2-3") full range cone drivers in a WG, and have true dipole radiation up through the highest octave. You could theoretically have a guide on both sides of the driver :)
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I like the idea of a tapered baffle if you are considering a 12" LF driver. Also, Have you considered two 10's as an option? This would allow you to keep the same baffle width and raise the mid/tweeter pair to a more normal seated height. I would be tempted to use all MCM drivers in that case, taking advantage of the quantity pricing on 4 or more. I just built a 2nd Hestia for someone else using the MCM driver in lieu of the Dayton. They measure extremely close, to the point where it's hard to justify the difference in cost. Also remember to look for promo codes. These will often save you 10-15 percent and sometimes free shipping.
Matavena, I have purchased the MCM and Vifa drivers but am considering a 15" for the bottom in
a tapered baffle to fit it. Would the DAyton PA380 be a viable driver to mate with the top end? I know people swear by the Eminence Alpha 15 but the FR. and FS are lower on the Dayton, whats your opinion?
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Just a question to those who may know the answer.
I have been looking at possibly using this: http://www.parts-express.com/pe/showdetl.cfm?partnumber=310-308
This would be keeping with the low cost solution, and may assist those looking for a way to power the low end. I do not have the stuff for the kit, but maybe someone could throw this in (only $27, keeping my fingers crossed) and test it out.
I may be picking up this tiny amplifier soon, so I may be able to report on it.
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Matavena, I have purchased the MCM and Vifa drivers but am considering a 15" for the bottom in
a tapered baffle to fit it. Would the DAyton PA380 be a viable driver to mate with the top end? I know people swear by the Eminence Alpha 15 but the FR. and FS are lower on the Dayton, whats your opinion?
Hey Squid,
Can I ask how you plan to drive the PA380?
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Just a question to those who may know the answer.
I have been looking at possibly using this: http://www.parts-express.com/pe/showdetl.cfm?partnumber=310-308
This would be keeping with the low cost solution, and may assist those looking for a way to power the low end. I do not have the stuff for the kit, but maybe someone could throw this in (only $27, keeping my fingers crossed) and test it out.
I may be picking up this tiny amplifier soon, so I may be able to report on it.
That amp will not drive the low end in OB with any authority. Possibly the top.
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Hey Squid,
Can I ask how you plan to drive the PA380?
The same way as the original design, maybe just the next size up amp. Still mono for
the bass drivers (8 ohm drivers) Crossover just like the original design but making the baffle
wider on the bottom to fit the 15". I love the design but wondering if it would be possible to
make a single baffle to be truely full range w/o the need for a sub?
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The same way as the original design, maybe just the next size up amp. Still mono for
the bass drivers (8 ohm drivers) Crossover just like the original design but making the baffle
wider on the bottom to fit the 15". I love the design but wondering if it would be possible to
make a single baffle to be truely full range w/o the need for a sub?
Total Q is fairly low on the Dayton 15" Pro Sound, which is why I asked. I believe it will be a better sounding driver than an Alpha, but you should consider a separate sub amp with built-in boost, around 6dB in the 30-40Hz range. The driver's lower Fs will probably not benefit you as much, but if you can compensate for the low Qts electronically, you should be fine.
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Total Q is fairly low on the Dayton 15" Pro Sound, which is why I asked. I believe it will be a better sounding driver than an Alpha, but you should consider a separate sub amp with built-in boost, around 6dB in the 30-40Hz range. The driver's lower Fs will probably not benefit you as much, but if you can compensate for the low Qts electronically, you should be fine.
Are you suggesting something different than the Yung amp? I thought just more watts with
same boost/features to power the bigger driver
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Are you suggesting something different than the Yung amp? I thought just more watts with
same boost/features to power the bigger driver
Sorry Squid, didn't remember our previous conversation. That combination should integrate well. You should be able to achieve slightly higher SPL's than the original design. Almost all dipole designs will ultimately be limited by the capabilities of the low frequency driver(s) and its ability to "keep up" with the rest of the system. I am very interested to hear your listening impressions when the design is complete.
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Matevana,I just wanted to make sure that the Dayton 15 had the right parameters for OB
Everything else will follow your design, I will let you know how things progress.
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Matevana,I just wanted to make sure that the Dayton 15 had the right parameters for OB
Everything else will follow your design, I will let you know how things progress.
I'm really stoked to hear about your design. Please consider doing a build thread so we can follow. You will be the 5th person that I am aware of to build some form of the Hestia. I have to say that they have all been extremely pleased, especially considering the cost.
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I'm really stoked to hear about your design. Please consider doing a build thread so we can follow. You will be the 5th person that I am aware of to build some form of the Hestia. I have to say that they have all been extremely pleased, especially considering the cost.
I actually got together with sjhomey (he is also doing a build) and swapped drivers, I had an extra pr.
of tweeters and he had an extra pr. of the MCM mids so it worked out great and will do a thread when
I get started building. Thanks for a great design
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I actually got together with sjhomey (he is also doing a build) and swapped drivers, I had an extra pr.
of tweeters and he had an extra pr. of the MCM mids so it worked out great and will do a thread when
I get started building. Thanks for a great design
That's awesome. Cant wait to get your listening impressions. Where are you guys located?
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The 51st state, South Jersey
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The 51st state, South Jersey
Haha... I'm in S. Florida, which is eventually where all people from Jersey wind up. I dont know of any OB folks down here.
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How true, probably half my friends from my youth now reside in the Sunshine State
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How true, probably half my friends from my youth now reside in the Sunshine State
Yeah, but you can probably chalk that up to Snooki and Jay-Wow :)
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I've spent the last week listening to a pair of Hestias on test baffles. Its all plywood and alligator clips. I am most impressed. My first exposure to OB and its all true. Big soundstage, depth, and detail. Thank you Matevana. I am using two sets of MCMs instead of a second pair of Daytons. Lots of bass response. Even with the Yung amp turned down my old wooden floors are jumping around. I've been trying different amps and moving the speakers around and like the openness and fullness of this design. I thought the top end was somewhat harsh at first, but that is disappearing. Could the top end drivers be breaking in after only 10 or 12 hours?
The only complaint I have is that even though the sound is very full I still can tell that it is coming from a point lower than my listening level, even with the baffles angled up. I would like to move the tweeter up to ear level somewhere around 33/36". As I see it I can add 10 or 12 inches to the bottom of the baffle and move the whole configuration up, which along with any other effects would decouple the bass from the floor. Or I could add more baffle and move the tweeter/mid up and leave the bass down leaving a gap in the middle of the baffle. Thirdly, I could add a second mid, wire the two in series and thus keep the same SPL as just one . I wonder if doing that would give more continuity from the tweeter down to the floor. I sort of like that third idea. Would these changes, which at the very least would add to the size of the baffle, compromise the design in other ways?
On a side note Matevanna I've been reading about the 2x rule of thumb, making the baffle at least two times as wide as any adjacent driver. What are your thoughts on that? You obviously didn't feel constrained by that rule on the Hestia.
The music is great. Thanks for making it easy and affordable for at least one rookie to enjoy the sound of OB.
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I've spent the last week listening to a pair of Hestias on test baffles. Its all plywood and alligator clips. I am most impressed. My first exposure to OB and its all true. Big soundstage, depth, and detail. Thank you Matevana. I am using two sets of MCMs instead of a second pair of Daytons. Lots of bass response. Even with the Yung amp turned down my old wooden floors are jumping around. I've been trying different amps and moving the speakers around and like the openness and fullness of this design. I thought the top end was somewhat harsh at first, but that is disappearing. Could the top end drivers be breaking in after only 10 or 12 hours?
The only complaint I have is that even though the sound is very full I still can tell that it is coming from a point lower than my listening level, even with the baffles angled up. I would like to move the tweeter up to ear level somewhere around 33/36". As I see it I can add 10 or 12 inches to the bottom of the baffle and move the whole configuration up, which along with any other effects would decouple the bass from the floor. Or I could add more baffle and move the tweeter/mid up and leave the bass down leaving a gap in the middle of the baffle. Thirdly, I could add a second mid, wire the two in series and thus keep the same SPL as just one . I wonder if doing that would give more continuity from the tweeter down to the floor. I sort of like that third idea. Would these changes, which at the very least would add to the size of the baffle, compromise the design in other ways?
On a side note Matevanna I've been reading about the 2x rule of thumb, making the baffle at least two times as wide as any adjacent driver. What are your thoughts on that? You obviously didn't feel constrained by that rule on the Hestia.
The music is great. Thanks for making it easy and affordable for at least one rookie to enjoy the sound of OB.
Hey SJ.
Thanks for the feedback. I can tell you from experience that they will only get better after another 75 - 100 hours of break-in, perhaps even twice as good as what you are now hearing. The D-19 tweets will mellow and the stiff accordions on the MCM's will loosen up; more importantly the Thiele-Small parameters will settle into alignment with the crossover design. For this reason you should continue to listen on the test baffle for a little longer, before coming to any design change decisions.
If you do decide to experiment with baffle height, I would strongly suggest keeping the upper MCM and Vifa D19 as a system, in the same relative distance to one another and with regard to the top of the baffle. I strongly recommend leaving the LF driver (in your case the 2nd MCM) in the same position as the original design. This is critical in dealing with floor bounce and not experiencing any 100-300 Hz suck-out as a result of cancellations. Moving the driver up will not decouple it from the floor, but rather change the critical integration with the mid/tweeter pair. You will likely experience a hole in the critical vocal region as a result.
If you decide to try adding a 2nd MCM driver in series, two things will likely happen. The crossover component values will need to be reworked as you will be changing the effective system impedance (16 ohms in series). You may also change the voicing of the Hestia design as a MMT, particularly off-axis.
From my tinkering, I found that a 13" baffle width for the mid/HF pair was the best overall compromise. Regarding the LF driver, you could certainly benefit from additional baffle width, perhaps as much as 20". In coming up with a design that might be easy for others to replicate, I chose a 15" overall baffle width and fine tuned the component values and driver spacing accordingly. I believe that Squidspeak has the right idea in considering a baffle that widens to accommodate the LF driver, similar to what John K did with his Nao Note design. This would minimize LF cancellation while preserving positive imaging characteristics up top.
I do not want to discourage you from trying what you propose, especially since you already have the 2nd MCM driver on hand for the other speaker. Just wanted you to consider some of the points above, so you may better anticipate the cause/effect relationship of the suggestions.
Ed
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Ed
Thanks for setting me straight. I will continue to listen for a while before I make any final changes on a permanent baffle. I did however make a few reversible changes. I lifted the baffles, first 6 inches and then 12, roughly, to see how tweeters at ear level would sound. Surprisingly to me it didn't change that much, although a little bit. Even on the floor the soundstage seems to be slightly above the baffles.
However, I think I did hear the floor bounce effect, you mentioned, when the baffles were elevated to 12 inches. Big time. I am listening about 8-10 feet away and when I sat forward the full sound was there. Sitting back about 18" or so and the vocals just went into a box. Nothing subtle at all. They attenuated dramatically. I assume it was a result of the floor bounce, especially on the lower midrange. I read some consider that floor bounce effects are minimal but what I heard was significant. At 6 inches high, I heard no negative effect at all.
I will listen quite a bit more, but I think I liked the sound a little better with the baffles a little higher. Definitely not 12 inches higher, in this room. What effect would splitting the bass and midrange drivers about 6 inches have? That is keeping the bass driver down where it is and lifting the mid/tweeter combo? Hopefully, I am not being too much of a pain with all these questions, I'm just interested in what different tweaks would do. I'll be following Squidspeak's progress on a wider baffle bottom.
Peter
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Hey Peter,
Not a pain at all :lol: You should be fine leaving the LF driver where it is on the baffle, and raising the Mid/tweeter to a more suitable height. Another thing you may wish to try, is to have the drivers cross a little bit forward of the listening position. If you think of your seated position, the left speaker and the right speaker, each as a point on a triangle, angle the speakers so their line-of-sight intersects about a foot or two in front of your position. Many people find this to have a positive effect in OB. It will also increase slightly the distance of the wall behind the speakers, w/o changing the relative position.
I may be partial to floor standing designs, so the fact that the tweeter level is lower than the seated ear level doesn't bother me. I find that angling the panels back slightly helps compensate for this, but others may prefer the height you suggest. I like to look at SL's Orion as one of the pinnacles in OB design; if I remember correctly he has the mid woofer around 34" off the ground, and the tweeter around 42".
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Ed
Thanks for setting me straight. I will continue to listen for a while before I make any final changes on a permanent baffle. I did however make a few reversible changes. I lifted the baffles, first 6 inches and then 12, roughly, to see how tweeters at ear level would sound. Surprisingly to me it didn't change that much, although a little bit. Even on the floor the soundstage seems to be slightly above the baffles.
However, I think I did hear the floor bounce effect, you mentioned, when the baffles were elevated to 12 inches. Big time. I am listening about 8-10 feet away and when I sat forward the full sound was there. Sitting back about 18" or so and the vocals just went into a box. Nothing subtle at all. They attenuated dramatically. I assume it was a result of the floor bounce, especially on the lower midrange. I read some consider that floor bounce effects are minimal but what I heard was significant. At 6 inches high, I heard no negative effect at all.
I will listen quite a bit more, but I think I liked the sound a little better with the baffles a little higher. Definitely not 12 inches higher, in this room. What effect would splitting the bass and midrange drivers about 6 inches have? That is keeping the bass driver down where it is and lifting the mid/tweeter combo? Hopefully, I am not being too much of a pain with all these questions, I'm just interested in what different tweaks would do. I'll be following Squidspeak's progress on a wider baffle bottom.
Peter
[/quoteHey SJ, wanted to check up on the build, I still have not started but , I am definetly gonna go
with the Dayton 15 on the bottom and everything else in line with original (awesome) design.
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One interesting permutation of the Hestia design is to swap the location of the LF and Mid drivers to produce a more forward sounding and prominent mid range. The Dayton's slightly higher efficiency may also be a better choice for those looking to drive the Hestia with a SET amp. (Overall efficiency raises to about 92dB)
Without a crossover mod, the Dayton Pro Sound driver sounds too proud as a dedicated mid range within the context of this project. The mod referenced below provides a notch in addition to addressing a rising impedance condition which may otherwise be an issue for tube amps.
I now have two sets of Hestias configured each way... Both sound great but with slightly different tonal characteristics. The cool thing is you can try both options without having to change drivers or baffles, for just a few bucks in reisitors and caps.
(http://www.audiocircle.com/image.php?id=69093)
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Hi Squid
I'm working on the permanent baffles, flush mounting the drivers, so lots of router work. I am moving the tweeter/midrange combo higher on a taller baffle to get them closer to ear level. In the meantime they sound sweet on the test baffles. You are going to like them.
Peter
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Hello everyone, I am new here.
I was just browsing to see if anyone else had done a project with these drivers from MCM.
Glad to see it was an OB design as well. The Hestia project caught my attention as I have a pair of speakers currently using the 55-2981 drivers but for the low end in a very large ported box with the mid being OB.
I was contemplating about using the driver for mid purposes as well in a OB replacing the current top I have. When I saw this It got me thinking it might actually be probable. I would however need to make the baffle larger on top but still make it look nice.
heres a pic of the project while being constructed still.
(http://www.audiocircle.com/image.php?id=69530)
also the bullet driver has been replaced with a Vifa dome (don't have the number off hand but I know it was used in the orient express by Zaph Audio). As I had not liked the sound/ harshness of the bullet.
The project is crossed currently with a cx3400 but hoping to swap that out soon with a dbx or digital unit as the current active crossover has some quality issues.
I am really interested in using a plate amplifier with these if I converted it to a half passive/active setup. With the top being the top half Hestia design. Thinking about using the PSC2.400 by hyphex.
any questions comments or concerns please inquire.
I would also like to note that the drivers from MCM have changed to a different model/design. The RMS is lower the cast frame slightly different and the paper cone almost looks identical to the Dayton shown here. I have
no idea how these sound as I have not tried or tested them in any way. Just a heads up.
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Hi Lynx,
Thanks for sharing your design. Some similarities between what you have done (and want to do) and the Hestia. I havent had a chance to hear the Hypex plate amps but understand they are nice. I've been very favorably impressed with the Yung models sold be PE. I have moved that to the top of my list, previously reserved for the Bash amps. The Yung are at a slightly lower price point and appear to have the edge on quality as well. I am on the fence between models with and without boost for OB. This may depend on the particular driver more than anything else, but a switchable boost would be a nice feature.
Completely agree with you about quality issues with several Behringer crossovers. I've played with many over the years and really like the dBX 223 and 233 series, as well as most of the models by Ashly. Not completely sold on the Driverack models, or many other all digital x/o's for that matter.
I've been talking to someone on another site who is building a slot loaded open baffle sub using 6 of the MCM select drivers. He bought both the 10's and 12's. His order for the 12's were mixed, both old and new, while the 10's were all original, the same used in the Hestia. He said the thickness of the cast frame has been reduced on the new drivers (i.e., cheaper) but the T-S parameters were similar. The cone design has also been updated. Hasn't had a chance to do much more than test them at this point.
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Those Yung amps seem to get a lot of good reviews. I like the power output and lightweight. Will most likely go with this route as it seems to be the cheapest method to get good quality bass amplification. So which one would be better for this project. The one with 0db boost or 6db? Another question would be how I should hook up the signal. A lot of my current setup is pro audio oriented. PC to Sound interface (presonus audiobox) to mixer, to behri dsp1424 (to limit noise/gains/hard limiter), to EQ (room correction/other) to active crossover, to amplifiers (1 of which I don't like). Should I hook the plate amplifiers after the crossover (is the crossover in the yung disable able?) or would this be to much input voltage? Or hook from the sound interface before mixer?
Might have been a lot easier if I hadn't given my dad my old Newcastle 965r.
The Hestia designs seems to be for relaxing on the couch listening to music or watching cinema where as mine currently are for standing walking around/party. As the tweeters are at standing level.
As far as the speaker is concerned is the 15" baffle necessary? Currently the baffle is at 12" but putting some molding or reworking the baffle all together shouldn't prove to difficult. I would have to have a new baffle anyway for a offset tweeter in the design anyway. My router died on me leaving me with just my rotozip and its circle cutter (so no driver sinking T_T) I know that it makes a huge difference for tweeters but what about mids and woofers?
Also I hope the new driver style sounds the same as the current ones because I'm very impressed with them. When I first tried the originals out they sounded far from appealing. But after playing them it warms my heart sometimes knowing that I just bought those for 25 a piece. Breaking these in are a must, Spectacular.
If anyone wants I can post a pic of the new cone style.
I would love to hear the slot loaded sub project also.
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Those Yung amps seem to get a lot of good reviews. I like the power output and lightweight. Will most likely go with this route as it seems to be the cheapest method to get good quality bass amplification. So which one would be better for this project. The one with 0db boost or 6db? Another question would be how I should hook up the signal. A lot of my current setup is pro audio oriented. PC to Sound interface (presonus audiobox) to mixer, to behri dsp1424 (to limit noise/gains/hard limiter), to EQ (room correction/other) to active crossover, to amplifiers (1 of which I don't like). Should I hook the plate amplifiers after the crossover (is the crossover in the yung disable able?) or would this be to much input voltage? Or hook from the sound interface before mixer?
Might have been a lot easier if I hadn't given my dad my old Newcastle 965r.
The Hestia designs seems to be for relaxing on the couch listening to music or watching cinema where as mine currently are for standing walking around/party. As the tweeters are at standing level.
As far as the speaker is concerned is the 15" baffle necessary? Currently the baffle is at 12" but putting some molding or reworking the baffle all together shouldn't prove to difficult. I would have to have a new baffle anyway for a offset tweeter in the design anyway. My router died on me leaving me with just my rotozip and its circle cutter (so no driver sinking T_T) I know that it makes a huge difference for tweeters but what about mids and woofers?
Also I hope the new driver style sounds the same as the current ones because I'm very impressed with them. When I first tried the originals out they sounded far from appealing. But after playing them it warms my heart sometimes knowing that I just bought those for 25 a piece. Breaking these in are a must, Spectacular.
If anyone wants I can post a pic of the new cone style.
I would love to hear the slot loaded sub project also.
My recommendation on the Yung amps would be as follows: If you get the 200 watt amp, I would opt for the bass boost. If you get the 300 watt amp, it's a toss-up, but I might opt for the one w/o boost. Regarding making the connection, I'm a big fan of less is more. I split the output from my CD player with a high quality RCA male to 2 RCA female adapter. Then run one cable to my amp and another to the subwoofer amp. That's it! Amazing how good it sounds when it's such a direct connection; no preamp, no miles of circuits and grounding points to degrade the signal, especially in the analog stage.
The 15" baffle width is critical to the design, as the crossover has been voiced to work with these dimensions. You can add wings to the back of a 12" panel, to get the rough equivalence of a 15" flat panel. In this design, I wouldn't worry too much about countersinking the woofer or midwoofer; it's always best to flush mount the tweeter as you have pointed out. I angle my Hestia back about 10 degrees, which provides good interaction at the seated distance in my set-up. Most critical is planting the woofer as close to the floor as possible; the midwoofer and tweeter can be raised if you like; just remember to keep the relative distance between those two drivers the same.
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Finished up a set of Hestias about a week ago. They sound great. I flush mounted the drivers which took quite a bit of router time, but overall a straight forward project. Also, I moved the mid/tweeter combo higher on a taller baffle closer to ear level. The sound between the HF and LF is very cohesive despite the gap in between.
Matevana if it is not akin to asking the alchemist how he makes gold, would you mind describing the process you went through to design the crossover?
And also, what's next?
(http://www.audiocircle.com/image.php?id=70659)
(http://www.audiocircle.com/image.php?id=70658)
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SJHomey,
Nice build! I hear you saying there is plenty of bass...how large is your listening area? You don't feel a need to augment with a subwoofer? I almost ordered drivers/plate-amp/components for the Hestia last week, but decided I really need to finish my Frugal-horn build first. My speaker building has slowed to crawl while my wife and I get situated in a new home.
Pete
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Since they're on sale now for $99 each I purchased a pair of Yung 300 plate amps. These class d amps extract some nice tight bass from the Alphas. They're compact, very powerful and produce little heat. I couldn't be more satisfied. I opted for ones without bass boost.
(http://www.audiocircle.com/image.php?id=70666)
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I really want those yung amps.. at 99 for the 300w model i am very tempted but alas my funds are limited atm. Argh! Also are those the visaton fullranges you have there poultry? interesting looking setup with the plate amps boxed like that on the shelf. Personally i think i would put in on the base of the speaker somehow so it can walk around with where i place the speaker. but you would need long reference cables. so what you have there looks like a pretty sucessful and inexpensive subwoofer set top amplifiers.
Also great job Sjholmey. Those look great... very bright red though :D
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Thanks for the compliments. I found some edge glued panels of three or four inch boards at one of the big boxes. The wood wasn't special but I liked the patten of the boards and I wanted them to pop a little. The idea was to stain the panels and then finish with a high gloss. But they came out basically red. They aren't as red as the photos show, but when the lights are low and the tunes are playing its all good.
I haven't lived with a subwoofer. The Yung amp can make the floor shake, but of course that isn't the same as LF extension. I have a sub box half built in the shop so maybe I'll have to get that finished.
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I've tried subs with my Alphas in flat baffles and in H-frames and IMO they detract more than they add. I guess I have a problem with how a sealed sub loads a room. To me it's not natural. The Alphas may not be everyone's choice but I like their bass weight and fast transients. The Yung class D amps add detail I wasn't getting with SS amps. I listen to mostly jazz and I'm hearing more wood and string resonance when bass players use that "slap style"of picking.
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I've tried subs with my Alphas in flat baffles and in H-frames and IMO they detract more than they add. I guess I have a problem with how a sealed sub loads a room. To me it's not natural. The Alphas may not be everyone's choice but I like their bass weight and fast transients. The Yung class D amps add detail I wasn't getting with SS amps. I listen to mostly jazz and I'm hearing more wood and string resonance when bass players use that "slap style"of picking.
Completely agree with Poultry here. Unless you cross to a sub very low there seems to me something disjointed in merging flat panels with separate sub enclosures. Perhaps it's a phase or time alignment issue, (or both) but what sounds OK initially eventually leads to dissatisfaction when you listen critically. I spent countless hours with digital delays and really wasn't able to make up for this effect. I've practically abandoned the idea now, in favor of locating all of the drivers on the same approximate plane. I do like attempting to alter the plane slightly to better align the driver's acoustic centers, but that's all.
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Matevana if it is not akin to asking the alchemist how he makes gold, would you mind describing the process you went through to design the crossover?
And also, what's next?
Really nice job on your Hestia build! I imagine the elevated height of the top driver pair makes a big difference in your environment. I'm sure you will have many happy hours of listening.
I tend to cheat a bit in coming up with crossover designs. I used to start with formulas and then tweak, but while this worked effectively in ball-parking component values, it did little to actually sample the drivers in their respective ranges and determine the best operating range, minimal distortion and power curves for each. In fact, a dipole's rear wave can sound very different when sampling larger vs. small drivers operating over the same range, if that makes any sense. Crossover calculators do not take these things into consideration.
Instead I use an Ashly 2001 active crossover to experiment with all the drivers on the test baffle. Within seconds you can alter crossover points, select from LR, Bessel and other x/o properties, and compensate for various driver levels. I spent days doing this with the Hestia, design, which is only a simple 2.1 way system. This is how I came up with the rather unusual crossover values, which at first seemed counter-intuitive (until you listen to the Hestias). I then attempted to duplicate these properties with passive components. Never would have arrived at the same conclusion w/o being able to sample and dial-in values on the fly.
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And also, what's next?
Been hard at work for the past few months on the next natural progression for me. Inspired by the recent designs of the Linkwitz LX-521 and John K's Nao Note II RS, which seem more similar then they are different. It's encouraging to see how two of the best known OB guru's arrived at similar design conclusions after decades of experience. I'm currently playing with an interesting 4-way design. In a nutshell, the basic design goals are:
1) Tall thin panels addressing off axis response and imaging.
2) A unique H-Carriage to house the bass driver.
3) Active/passive hybrid.
4) Time aligned baffle design.
5) Advanced construction techniques (that anyone can replicate) minimizing cabinet vibration.
6) Form vs. function artistic concept.
I'm testing some interesting drivers right now. Nothing final but I'm favoring an Usher 8" driver in an incline-H for bass duties. I love the fast articulate response and it's ability to cross slightly higher than normal. A Peerless 6.5" aluminum driver for the lower mids. Still loving the inexpensive Vifa D-19 for the highs, this time crossed very high. Jury is still out on a critical 4-5" midrange which will round out the quartet. Right now I'm testing three drivers here; a CSS FR125, as well as a Seas 4" fullranger and a Scanspeak 4" driver. This design will obviously cost a bit more, but I'm interested to see it all come together. Sort of a big sister to the Hestia!
(http://www.audiocircle.com/image.php?id=70687)
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Matevana, Soooo, If a bit more bass SPL was desired, using Sjhomey's build for example, one could throw another MCM woofer into the longer baffle without issue?
Pete
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Matevana, Soooo, If a bit more bass SPL was desired, using Sjhomey's build for example, one could throw another MCM woofer into the longer baffle without issue?
Pete
Pete, the short answer is yes. If you were to do that, I would recommend using two plate amps, running in dual mono (separate left and right channels). The reason for this is not so much additional watts, but as you raise the woofer on the baffle it will likely become more directional. Also, since the MCM driver is somewhat limited in mid frequencies, the Hestia design is well balanced using one bass driver. So you will gain bass SPL with a second bass driver, which you may or may not end up needing. The plus side is that each driver will work half as hard, and you are likely to see performance gains as a result (less excursion = less forces acting on the baffle).
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Finished up a set of Hestias about a week ago. They sound great. I flush mounted the drivers which took quite a bit of router time, but overall a straight forward project. Also, I moved the mid/tweeter combo higher on a taller baffle closer to ear level. The sound between the HF and LF is very cohesive despite the gap in between.
Matevana if it is not akin to asking the alchemist how he makes gold, would you mind describing the process you went through to design the crossover?
And also, what's next?
SJ, looking good. My whole shop was totaled by the storm, so I was very happy to see the tweeters
I sold you in your project. The MCM woofers I got from you survived, but pretty much every thing I owned
was under 4 ft. of saltwater. Gotta relocate,but determined to build my Hestia's Good day, Squid
(http://www.audiocircle.com/image.php?id=70659)
(http://www.audiocircle.com/image.php?id=70658)
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My whole shop was totaled by the storm, so I was very happy to see the tweeters
I sold you in your project. The MCM woofers I got from you survived, but pretty much every thing I owned
was under 4 ft. of saltwater. Gotta relocate,but determined to build my Hestia's Good day, Squid
Squid,
Sorry to hear about your run-in with Sandy. If I can help with anything, let me know.
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Squid
I'm really sorry to hear about the damage to your shop. When you hadn't posted I was hoping that you were busy with cleanups and repairs in the area. I can only imagine what you are going through. That was one bad storm. Speaker building pales in comparison. We were lucky here. The eye passed over us and it was still for two hours and then hit with a fury from the south for the rest of the night. But flooding damage was relatively light. I hope your home fared well and you are able to put things back together, in time, at your shop. I am sure it will make doing business very difficult for some time. My best to you and your family.
Peter
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Thanks, Pete It really brightened my day when I saw your build. Looks great BTW
House and family OK, just a nightmare with the shop and boats. Gonna move shop Inland
so When I get set up and running I'll get back to my hobby/passion.
Thanks for your concern, Squid
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Pete, what's next for you. The Hestia SL. BTW moved shop inland and will take a month to
set-up. Really like to have DIY event in June in new shop, South Jersey represent! OB, box,
whatever., Thoughts?
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Dear matevana, sjhomey and Poultrygeist
I am living in Germany and want to build my first pair of speakers. I have owned various speakers over the years including Rega floorstanders (R3s) and now Tetra 120Us. I want to get away from the box sound and decided to go the DIY route but my DIY skills are not great and have been looking at open baffle designs these last few months. Originally I was going to build Poultrygeist's last project with the Eminence Alpha-15A 15" Driver and the Neo3 tweeter but then I came across the Hestia OB and love the simplicity of this design and the fact I could use most of my existing kit (except for the need to get plate amps).
My existing equipment is as follows:
Dussun DS99 Integrated Amplifier http://www.dussun.com/english/ds99.html
Mapletree Audio Ultra4A Pre-amp http://www.tnt-audio.com/ampli/mad4multra_e.html
Musical Fidelity V-DAC II with Hiface 2 USB to SPDIF converter
PC with Vortexbox installed
Modified SL1200 MKV turntable
Tetra 120U speakers
A couple of newbie questions:
1) What size holes do I need to make for each driver? I have access to a jigsaw so think I can manage cutting some circles.
2) sjhomey - can you give me the measurements of your entire baffle and the driver heights. Thanks. For someone with relatively zero woodworking experience how difficult would it be to flush mount the drivers?
3) What do you use for the seal of the drivers to the baffle?
4) What about screws for each driver? How tight should the screws be?
5) I can solder but I am pretty dumb when it comes to reading circuit diagrams. Would you be able to post one or two “looking from above” shots of the crossover.
6) Are there any better alternatives to the tweeter in terms of sound quality given the relatively low cost of this project? Crossover impacts?
7) sjhomey - what binding posts did you use at the bottom of the baffle?
8 ) I was thinking the Dussun could drive the midrange and HF drivers. Do you see any issue with the set up?
Many thanks for all your collective help.
Newbie7800
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Danger
In the above post the adress www.dussun.com leads to a trojan virus in Romania
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Hi Rudolf
I just googled Dussun to find my old amp and copy and pasted the link after checking it. I have AVG installed and it did not identify a threat. Anyway the specs for my amp can be found by googling Dussun ds 99 and Goodsound.
Will check my machine tonight. Thanks for the warning.
Newbie 7800
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To be exact it is http://www.dussun.com/english/ (http://www.dussun.com/english/) only.
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Newbie7800,
With regard to your question about tweeter alternatives, I have had good luck with the Vifa XT19 in the new Hestia-SL project. I would consider it an upgrade to the D19 due to it's dual radiator design and it's ability to be crossed lower w/less distortion. It is however a 4 ohm nominal design, so you would need to compensate for one coil and cap in the current crossover design. If you decide to make the change, the Hestia will still maintain the same signature as the two Vifa products are voiced similarly.
Take a look at the Parts Express and MCM websites for overall driver dimensions and cut-out dimensions. If you are not familiar with routing recesses, I would recommend just surface mounting the drivers. Within the context of this project, the off axis frequency response will not suffer all that much by not flush mounting the drivers.
I hope that helps.
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Dear Matevana
Thanks so much for coming back to me and helping me start this journey :-). Had no idea the cut out dimensions were mentioned on the driver pages. Sorry.
On the tweeter, this sounds good but whilst I understand what you mean by coil and cap I have no idea about what "compensate" means in terms of implementing the change to the crossover design. Sorry, I am really starting from scratch here. Any support you can give here would be great. Thanks.
Would you mind pointing me in the right direction for the following two questions:
(i)What do you use for the seal of the drivers to the baffle?
(ii) What about screws for each driver? What type and how tight should the screws be?
I will take your advice about the routing :-).
Thanks for your support. I really want to give this project a go and I just need a push in the right direction :-)
Newbie 7800
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Newbie,
If you take a look at the schematic in post # 13, you will need to substitute two of the components to accommodate the lower nominal impedance of the XT19 tweeter, namely capacitor (C2) and inductor (L2). Some good ballpark values would be obtained by doubling the capacitance (to around 11uf or 12 uf) and halving the inductance (to around .70 mH). This will get you real close to the original intended crossover points of the D19 tweeter. The two tweeters are close enough in sensitivity where you should be OK just by swapping the two components mentioned above.
Parts Express is a good source for driver mounting hardware. They sell self adhesive gasket material but open cell foam type weather strip will also work well. While this may be more of a factor in closed box designs, (to prevent air leaks) it's still good to use foam to help prevent any mechanical noise from occurring when the driver comes in contact with the baffle. I use black pan head wood screws to mount my drivers, either 1/2" or 3/4" in length depending on the frame depth and baffle thickness. I personally do not like T-nuts, and opt to screw the drivers directly into the baffle, though others may disagree. Torque the screws evenly by hand in a star pattern, to prevent warping the driver's frame. Hand snug should always be sufficient and it's a good idea to repeat the star sequence a day or two after the drivers are initially mounted once everything has settled-in.
Please let me know if you have any other questions.
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Dear Matevana
Thanks so much. For now I have loads of information to get started. I may have a question or two once it comes to actually finalising the cross over but I will certainly use the info you provided first. Will let you know how it goes. Really grateful.
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Newbie
The bottom of my woofer is 2" from the bottom of the baffle. The bottom of the midrange is 22" from the bottom of the baffle and the baffle is 35 1/2" tall. As Matevana has mentioned the important thing is to keep the mid/tweeter as a unit per his plans and to keep the woofer close to the floor. I raised mine to 2" and I think he has his at 1".
If you have a router flush mounting is relatively straight forward but very time consuming. I surface mounted my drivers on a pair of scrap plywood baffles at the beginning. I would recommend surface mounting and get the speakers playing and then worry about how you want to configure the finished baffles later. It is quick and cheap to do so.
I can post a photo of the crossover but I've included the parts list I ordered from Parts Express. If you buy the boards if is very easy to see where everything goes using Matevana's key which I think is on the first page here.
You mentioned buying two plate amps. Matevana's design calls for using 1 in mono. From what I am hearing that seems quite adequate. They are probably the single most expensive part of the project and only buying one saves a few bills. As you can see I paid $140.00 for mine but I noticed fairly recently they were on sale for around $100.00.
Good luck and keep posting.
QTY PartNumber Product Price Ext. Price
2 091-1260 Dayton Audio BAGS-G Banana Speaker Plug 2 Pair $12.95 $25.90
1 365-255 Jasper Circle Jig Model 400 $26.62 $26.62
6 091-1245 Dayton Audio BPA-38G HD Binding Post Pair Gold $8.48 $50.88
1 260-542 Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll $7.64 $7.64
8 269-265 Rubber Cabinet Foot 1-1/4" Dia. x 1-1/2" H $0.40 $3.20
1 Economy Shipping $0.00 $0.00
QTY PartNumber Product Price Ext. Price
2 027-556 Solen 5.6uF 400V Polypropylene Capacitor $4.23 $8.46
2 027-562 Solen 7.5uF 400V Polypropylene Capacitor $5.51 $11.02
2 091-1045 Dayton RCAAD-MFF RCA Male To Dual Rt Angle RCA Female $8.81 $17.62
2 264-500 Vifa D19TD-05 3/4" Poly Dome Tweeter $16.88 $33.76
1 CATALOG FREE CATALOG $0.00 $0.00
2 255-258 Jantzen 1.4mH 18 AWG Air Core Inductor $10.58 $21.16
2 255-264 Jantzen 1.8mH 18 AWG Air Core Inductor $11.79 $23.58
2 260-130 Crossover PC Board 2-Way 12 dB $3.70 $7.40
1 301-510 Yung SD300-6 300W Class D Subwoofer Amp Module w/6dB@30Hz $139.88 $139.88
1 Economy Shipping $0.00 $0.00
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Dear sjhomey
Thanks!!!!
Thanks for the point about the plate amps especially. I am going to get myself a router but will first mount everything on scrap ply as suggested. Will only order everything after Christmas to avoid the Christmas rush.
Thanks for the help and I will post an update in the new year.
Newbie
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I hesitated (hestiatated?) a few days too long to order from MCM...they show a 90 day back-order on the 55-2981 drivers. I received all other needed components from Parts Express. Thankfully all is not lost...I will likely fill at least most of that waiting time finishing a pair of FH3's.
Pete
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I hesitated (hestiatated?) a few days too long to order from MCM...they show a 90 day back-order on the 55-2981 drivers. I received all other needed components from Parts Express. Thankfully all is not lost...I will likely fill at least most of that waiting time finishing a pair of FH3's.
Pete
Pete,
I have another pair of 55-2981 in boxes if you are interested.
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PM sent.
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Dear Matevana
There I was about to order everything and then realised the MCMs are 3 months on back order. .... :-(
Could I do the project with 4 Dayton Audio drivers? I saw your changed cross over design for the DA as the midrange driver so I think it is possible. What do you use to drive the DAs when you swapped them around? I am worried that at 300w my dussun would struggle to drive the DAs as midrange drivers. Using the MCMs I only had to invest in the plate amp. Any suggestions, otherwise I will order the MCMs and just sit it out and wait.
Thanks
Newbie
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Newbie,
I do not recommend using the Dayton drivers in the original Hestia design as a midrange driver. For one, the presentation is different and it will change the overall character and sound. Additionally, the Dayton's will require a Zobel network (and possibly a trap) and the MCM's will not, which would ultimately make your crossover more complex. If you don't mind the wait too much, I would suggest opting for the MCM stock to be replenished. Sorry about that!
Driving the Dayton's wouldn't be an issue with your equipment. The bigger concern is that the MCM's have an early roll-off which plays into the overall design and it's proper integration with the D19. The Dayton's have a somewhat forward sounding midrange which would require additional components to tame them.
Note that the Hestia design is actually very efficient. The mids can be driven with as little as 15-20 wpc. Higher powered amps usually have higher damping which will take better control of the driver's motor. I am using a Crown D-75a for both my original Hestia's and the new Hestia-SL. The D-75a is a very high quality, well damped broadcast quality amp, that can be purchased used for a fraction of their original cost. They are only 40 wpc and one of the best kept secrets in home audio.
Ed
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Thanks to Ed's well-stocked driver supply, I now have all the hardware needed to begin the Hestia build...yahooo! In reading some of the posts, it seems the baffle can get a pretty good work-out with some volume. Would it be recommended to have at least 1" baffle thickness...possibly doubled-up 3/4" BB?
Pete
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Plund
I would recommend throwing together a pair on test baffles first. I used scrap 3/4" plywood. Its quick and would answer a lot of questions and also get you listening to them pronto. I went with a taller version and have a fair amount of vibration. I am driving them with only a 25 watt amp so they are not dancing across the floor, but a hand placed on the baffle can feel the vibration. I don't know how much it robs from the efficiency, they sound great. Matty speaks of them being laid back in comparison with the SLs, but they sound precise and revealing to me. I can now hear the lyrics. I am doing a slow build of the SLs, waiting for parts to go on sale, so at some point I will be able to compare.
Matevana suggested to me somewhere above to use the c channel from the conventional shelving systems sold in the big boxes to stiffen baffles. I think he said somewhere that that solution might even work bettrer with a thinner baffle. Test baffles would allow you to play around with different configurations.
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Pete,
Glad to hear you're getting ready to start the build! A few things to keep in mind. Those who speak of baffle vibration built their versions with larger baffles to accommodate either larger bass drivers or wanted to elevate the drivers. If you plan to build with the stock dimensions, the driver frames will keep the baffle free-space from vibrating excessively. You should not need to double up on baffle thickness. If you do, you may want to chamfer the rear opening so you don't create a tunneling effect (with its own resonance) from the extra thick baffle.
It's funny but the only negative aspect of building test baffles is as follows. In two situations that I know of, the individuals enjoyed listening to the test baffles so much, they never got around to building finished ones!
Keep us informed on the build!
Ed
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Well I guess use the most paint splattered, splintered,stained junk you can find as a safeguard. Building and finishing the baffles is the most time consuming part of the build.
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Well I guess use the most paint splattered, splintered,stained junk you can find as a safeguard. Building and finishing the baffles is the most time consuming part of the build.
Or an old baffle that says "Bose" :duh:
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Thanks for the info on baffle vibration...I will plan to use 3/4" birch and keep the height close to the original (possibly stretch it two inches).
I can see myself as one of those who would never get the drivers moved from the test baffle to the finished version...for that reason I will skip the test baffle. I trust the testing you have already done! :)
My question is... will I like/prefer OB? ...I will find out. :wink:
Pete
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Has anyone tried the Hestia OB with either 2 of the 10" woofers or a 15" so as to get more SPL.
Thanks from a newbie.
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Has anyone tried the Hestia OB with either 2 of the 10" woofers or a 15" so as to get more SPL.
Thanks from a newbie.
That's herecy, lol! I'm aware of one build where the 12" version of the MCM driver was substituted for the ten, and another build with the Hestia top end and a separate H-Frame enclosure with one Eminence 15" Kappalite 3015LF. I have heard the latter and it sounded great... maybe not as balanced as the original design but good for rock, etc.
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Thanks for replying to my post. I tend to listen to rock and blues and sometimes it is fun to listen to it a little louder than usual so that is why I asked about either a larger driver or multiples. I currently have a pair of Speakerlab Cornerhorns which of course have plenty of bass and pack quite a wallop. Will open baffles have any where near the bass? Or should I be thinking of a sealed sub to go with the OB? Thanks.
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Thanks for replying to my post. I tend to listen to rock and blues and sometimes it is fun to listen to it a little louder than usual so that is why I asked about either a larger driver or multiples. I currently have a pair of Speakerlab Cornerhorns which of course have plenty of bass and pack quite a wallop. Will open baffles have any where near the bass? Or should I be thinking of a sealed sub to go with the OB? Thanks.
When I first got interested in OB I didn't know what to expect. You almost have to hear OB bass for yourself in your own room and then determine whether you want to augment it in any way. The short answer is it sounds different. The unboxed drivers can go fairly low and be very precise but the sound interacts with the room differently. Low frequencies don't pressurize the room as they might with boxed subs, and you will probably hear things in the music that you have never heard before. It's almost a quality vs. quantity issue. It's a little bit like making the change from Coke to Diet Coke. If you had to switch back after some time, you might miss the crispness and refreshing taste and be overwhelmed by the super sweet syrupy taste. Sorry for the cheesy soda analogy, but for someone who hasn't heard OB bass it helps put things in perspective.
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Ed,
The "Hestia's" I have been working on are not quite finished yet, but last week I got to the point were I was able to connect to an amp and achieved "first sound". Connected to my model 912 Pioneer solid sate receiver and in my 15x17 bedroom they sound AWESOME! ... Very nice design you created...thanks for sharing! I have moved them to a larger "Bonus Room", were I can comfortably keep them a few feet out from the wall...they will be part of another system being put together. Before removing from the bedroom, I enjoyed listening to their large, well-rounded sound and after several hours of listening didn't want to stop. :) I find them well balanced, with plenty of bass (and I do Like bass). With the exception of adding 6 inches distance between the MCM Mid and the Dayton Woofer, I kept your original version's configuration.
I will attach a few pics when this pair is completed. Earlier this evening I epoxied magnets into the Hestia grills...grills are the only items remaining.
Pete
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Matevana, I just saw that the mcm 10 inch woofer is not available until the end of June. You have mentioned a possible 12 inch sabstitute, would the crossover stay the same or would it require changes? Did you have a chance to hear it? Thank you
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Ed,
The "Hestia's" I have been working on are not quite finished yet, but last week I got to the point were I was able to connect to an amp and achieved "first sound". Connected to my model 912 Pioneer solid sate receiver and in my 15x17 bedroom they sound AWESOME! ... Very nice design you created...thanks for sharing! I have moved them to a larger "Bonus Room", were I can comfortably keep them a few feet out from the wall...they will be part of another system being put together. Before removing from the bedroom, I enjoyed listening to their large, well-rounded sound and after several hours of listening didn't want to stop. :) I find them well balanced, with plenty of bass (and I do Like bass). With the exception of adding 6 inches distance between the MCM Mid and the Dayton Woofer, I kept your original version's configuration.
I will attach a few pics when this pair is completed. Earlier this evening I epoxied magnets into the Hestia grills...grills are the only items remaining.
Pete
Hi Pete,
Great to hear. I can assure you from experience that they will only get better over time due to the break-in characteristics of some of the drivers. I just moved my original Hestias into the bedroom after making some small changes. Don't forget to post some pics!
Ed
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Matevana, I just saw that the mcm 10 inch woofer is not available until the end of June. You have mentioned a possible 12 inch sabstitute, would the crossover stay the same or would it require changes? Did you have a chance to hear it? Thank you
Hi,
I haven't heard the 12" version myself in this design, though I do believe one of the folks on here built it that way. The original woofers are fairly polite where they meet the mid driver. This is important since the mid driver is allowed to roll-off naturally in this design. Worst case is the transition between the two drivers wont be as clean. If this becomes an issue for you, you may be able to clean things up a bit by inserting an F-mod (inline passive crossover) onto the interconnect that goes to your main amp. Something like the 100hz high pass F-mod should clean things up if necessary. This should allow you to use the original crossover design. Your setup would have to allow you to pass an unaltered signal to the plate amp separate from the line affected by the inline crossover; they have RCA splitters that do this if your amp/receiver doesn't allow for it. You may not need to do this if the results are satisfactory to you.
Ed
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Ed, Here are several pics of your Hestia's. I am pleased with the completed build, but even more pleased with how they sound! Thanks again for sharing your design! They are being enjoyed here at the opposite end of the country in Washington state.
Pete
(http://www.audiocircle.com/image.php?id=77553)
(http://www.audiocircle.com/image.php?id=77554)
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Killer job Pete! :thumb:
Like your interpretation of the baffle shape and grilles. Really nice touch! You should be proud.
Remind me how you decided to drive the Dayton woofers?
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I think incorporating into the Hestia a few things I like from other designs worked well in this pair. The grills and some solid legs are needed to help protect the speakers from toddler-aged grandkids. Hopefully those creative individuals, whose designs I borrowed from, feel flattered! :wink:. The Dayton woofers are driven by your recommended Yung 300 plate amp, supplied with the output signal from a DVD/streaming player.
Pete
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nice cost effective design im going to try it
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I think incorporating into the Hestia a few things I like from other designs worked well in this pair. The grills and some solid legs are needed to help protect the speakers from toddler-aged grandkids. Hopefully those creative individuals, whose designs I borrowed from, feel flattered! :wink:. The Dayton woofers are driven by your recommended Yung 300 plate amp, supplied with the output signal from a DVD/streaming player.
Pete
Pete,
Depending on your listening preferences, you may get favorable results from splicing an F-mod inline before the Yung amp. I use a pair (left and rigfht) of the 50Hz high pass F-Mod's on the Hestia SL's, which protects the smaller and less efficient woofer from over- excursion. I really like it for most program material. The 50Hz version gets you down by about 12dB at 25Hz, where there is little actual recorded material in music. It allows me to crank the woofers level without excessive distortion or worse. There is also a 30Hz version which might be better for the larger and more efficient 10" woofer on the Hestia Standard (requires less attenuation). Of course a lot of this depends on how loud you listen and the program material as well. You may not need it at all.
For about 25 bucks a pair, its an interesting filter to play with. There's also a guy on eBay who sells them in singles for less, if you are running a mono signal to your Yungs.
(http://www.audiocircle.com/image.php?id=77604)
I noticed your Hestia's are on nice plush carpeting. It's funny but living in Florida most flooring is done in tile and wood. I have never heard either the Hestia Standard or SL's on carpeting! :lol: I realize that's a bit unusual.
Oh yeah... and feel free to pull off that MCM decal on the back of the mids. I believe I did the first one for you! They look much better w/o them IMO.
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Ed,
interesting about the Fmod's. I am running mono to the woofers so $16 on ebay would get me there.
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I wonder how this would compare to the Fmod? I've seen them in 60hz.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=266-442
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I wonder how this would compare to the Fmod? I've seen them in 60hz.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=266-442
That particular link is for a low pass filter. To help prevent over-excursion you would want a high pass, somewhere in the neighborhood of 30 to 50 Hz depending on the driver, listening preferences, etc. Also, since F-mods don't mess with speaker level (they are line level) they tend to be more transparent in the system.
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Pete
Your Hestias look great. I like those grills. Are they made from PE parts?
These Hestias are a very good project in many ways. They are cheap, simple to complete, and sound great. In addition the designer is not only knowledgeable, but is engaged and always available for comment. And they sound great!
Thanks for posting photos. I wish every builder would. Its interesting to see different interpretations of the design.
Peter
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Pete
Your Hestias look great. I like those grills. Are they made from PE parts?
These Hestias are a very good project in many ways. They are cheap, simple to complete, and sound great. In addition the designer is not only knowledgeable, but is engaged and always available for comment. And they sound great!
Thanks for posting photos. I wish every builder would. Its interesting to see different interpretations of the design.
Peter
They look great, I cant wait to start my build. I got sidetracked by superstorm Sandy, and had to
start over with my shop and life. SJ homey, got my shop up and running and will get in touch. Mike
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Squidspeak, glad to hear you have your shop going again. I am sure it has taken much work on your part...says much of your character! Hopefully you are able to get to your build soon...I look forward to seeing your pics!
SJ, The only parts I used in the grill was 1/2" birchply, grill cloth (stretchy polyester type), and 1/4" x 1/4" disc magnets. The magnets were epoxied in place and the grill cloth was hot-glued. PE has the grill cloth and their 1/4" x3/16" magnets should be strong enough if the gap between the magnets is kept small. Else-wise, PE's larger disc magnet would work well.
Pete
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Well I am happy to say I'm finally ready to start this project. The Vifa tweeters were out of
stock for awhile but are available now. Anyway, I am going ahead using the Dayton 15" pro
driver for bass duties but everything else will follow the original design. I plan on making the baffle wider on the bottom to accomadate the 15 driver in proportion to everything else. I recieved the drivers and
amp the other day so hope to cut panels shortly. I want to document the build so may be asking for
help on posting pix, will update.
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Dear Matevana and fellow hestia builders
I have been meaning to write for a while. With some hiccups along the way including completely destroyed vifa tweeters and crazy shipping prices (could not get the MCM speakers with international shipping and had to use a freight forwarder) I have all the parts to start my build which I hope to do in september. The mcms had a rough journey and had moved in their boxes and the packaging was deformed but I could see no damage. Hopefully they will operate ok......
Will report back once speakers are built.
Newbie 7800
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Good to hear Newbie! I'm sure it was tough trying to source some of the stuff internationally. I guess we take some of that for granted in the states!
Been tinkering with some hemp cone guitar speakers lately. I really like the way they behave as a mid driver in OB. Very late break-up, velvety mids and attenuated highs. The high Qts is also a bonus. Been testing them in the 150 Hz to 2000 Hz range and have been very impressed. I see a new design in the future. A "Hempia" perhaps??
I can see a 2.5 way design using the Vifa D19 tweeters, the Usher 8" for bass duties and either:
a) Eminence 820H, 8" hemp code midrange (Qts .88, 96.1 db)
b) Eminence Lil Buddy, 10" hemp cone midrange (Qts .84, 98.8 db)
Both drivers are reasonably flat in the 150Hz to 2k Hz range and retail for 70-80 US Dollars.
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I have everything coming into build the Hestia OB. It will be my first experience with an open baffle project, and would like to confirm that I understand the crossover layout. Is the attached diagram I created the correct layout for all of the connections. I should be fine with constructing everything I just want to confirm that I understand the crossover connection points. Thanks for whomever can help. Looking forward to a Thanksgiving weekend project.
(http://www.audiocircle.com/image.php?id=90296)
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You got it right. Just remember to keep the order correct. It's turkey, stuffing, gravy, hestia. Let us know how it sounds!
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Thanks for the confirmation. Will test with plywood baffles and then plan to use hand planed solid cherry. Will let you know how everything goes. I am sure I will have a few more questions after I get into the project.
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Hey Ed, sent a PM your way. :-)
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For anyone interested in the Hestia, MCM has the 55-2981 on sale for $22.94 if you buy 4. Codes are AFC909, BF2013, CL115.
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Hi Matevana
Life gets in the way to actually starting the build. Have got everything but the screws :-).
You kindly told me that you tend to use pan head screws of 1/2 inch and 3/4 inch length. I looked on Parts Express and they have varying sizes. 6 and 8 are the two most common sizes when searching under speaker building. I know it is a basic question but can you tell me what size screws you used for the Hestia OB build and whether you used different screws on the tweeter vs the two woofers. Thanks!
Plan to build over Christmas.
Regards
newbie7800
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I used the #8 pan head screws from PE. If memory serves I used
1/2" on the tweeter and 3/4" on everything else. Hope this helps!
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Thanks!
Will let you know how the build goes :-)
Newbie7800
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Hi Matevana.
I have recently become interested in OB speakers, and I'm impressed with your build, the simplicity appeals me.
I would like to build something inspired by it.
Do you think it would be possible to have 4 of the MCM's pr side, still observing the distance between then as per the Hestia?
I have a 135 cm long ribbon speaker, that I plan to use from around 1200Hz and up.
The ribbon sounds great, and I hope to extend its openness to the frequency range below.
Regards,
Mikkel
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Hi Mikkel!
I think it is totally possible. Four of the MCM drivers per side wired series/parallel would yield an easy 8 ohm load and be very efficient. You may even want to consider a shallow H-Frame housing all drivers. or H-Frame on the bottom and open baffle on top. It would be possible to do that in a shallow cube as small as 25" x 25" x 12".
Ed
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Hi Ed, thanks for your reply.
25"x25"x12", does that imply you mean to put the drivers in a square, 2x2 arrangement?
I was thinking 1x4, along the ribbon. More in a line source inspired way, if that makes sense in the OB-world.
The H-frame could then cover the two lower drivers, perhaps?
Cheers,
Mikkel
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You could, but a 2 x 2 cabinet will give you more bottom-end, since two of the LF drivers will benefit from floor bounce. It really depends on how high you plan to cross to your ribbons. If you are hoping to get better vertical dispersion of the lower mids, the column approach will work well. However, if your ribbons are capable of producing ample low-mids, you would be better off crossing lower and having more of the LF drivers close to the floor, in my opinion. In the Hestia-Forte design, the 2 x 10 bass cabinets can be placed either vertically (like Orion) or horizontally (like Martin King's Lowther/Acoustic Elegance H-Frames). I much prefer the horizontal placement in that design.
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Good point about the low end.
I currently I am using the ribbons from around 1200 Hz, with a passive, fourth order filter. They can go as low as around 1000, but start to sound thinnish.
I think I'll start with two woofers horizontally in an H frame, and two stacked vertically along the ribbon.
For a start, they will be driven by the same amp, and thus receive the same frequency range, as I only have four amplifier channels. I am using a digital filter for the low end, and can match levels and do a bit of equalising that way.
Cheers
Mikkel
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If anyone is interested in building these, I have about 10 of the Dayton 10" pro sound drivers in a bulk pack. I will let them go in pairs only. Just make a reasonable offer.
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Hi Matevana. I have all parts to construct the Hestia using three mcm drivers per side. They were on sale for 14.95 over the holidays. I constructed the cabinets with a u frame for the bottom two woofers. I will be powering with a tpa3116 for the top end and a yung 100 watt plate amp for the woofers.My problem is that I am quite the novice in crossover building. I have seen the diagrams but do not understand them. Could you draw a simple picture of the crossover board with parts and solder points and speaker hook up. Thanks for sharing your knowledge and passion for our hobby.Lloyd Bruney
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Hi Lloyd,
Sure thing! See the diagram below for the connections. C1 and L1 represent the capacitor and inductor pairs for the tweeter; C2 and L2 for the woofer. Typically the (+) and (-) connections furthest from the speakers get wired to the (+) and (-) ends of a speaker terminal, so you can easily unplug the speakers as needed. If that still isn't clear just email me and we can go through it in more detail.
Ed
(http://www.audiocircle.com/image.php?id=95622)
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Hey Ed,
I suppose the Dayton 10" pro sound drivers are gone by now?
Thanks!
Rich
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Hey Rich,
Yes, they went quick. I basically did a BOGO (plus shipping) for those who might be interested in building one of the Hestia designs.
Ed
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Hello,
I am new here and new to OB speakers. I have been running an active 3 way system for years with box speakers and crossover points at 100Hz and 2800Hz.
Can you, Matevana, or anyone suggest a set of reasonably priced speakers for my first OB experiment that would work well with these x-over frequencies ?
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Another complete newb piping in...could the Hestia be made as a 2-way system (just the tweeter and the MCM doing all mid and LF duties)? If so, would a person want to keep them on the baffle where they are, or would centering them (top/bottom) drastically effect the sound?
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Hi JJ,
The short answer would be no. To effectively build this design (and many other OB designs) you need a way to bolster low frequency output if you're goal is to have a design that reproduces sound close to full range. This is necessary due to the 6 dB per octave roll off behavior that OB speakers exhibit. The easiest way to compensate for this roll-off is to have a dedicated low frequency driver (helper woofer whose volume is individually controllable). If you ask the MCM driver in this design to reproduce a range from Fs (it's resonance or lowest frequency) up through the crossover frequency of the tweeter, you will wind up with a curve that is anything but flat.
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Dear Matevana and fellow Hestia OB owners/builders
1.5 years from first thinking about this project I am almost there with lots of ups and downs for a total beginner. Pircture attached to prove I am actually progressing. Holes all cut and crossovers ready to build. I even understand the crossovers :-). However one simple thing stopped me tonight building them. How can I use the cableties to fix the coils. There is only 1 hole in the pre-etched boards from PXpress. It would be far easier surely with two holes. Can I drill extra holes. I looked at the pictures and I cannot see how to do it with just one hole securely. Sorry for such a simple and dumb question but it is stopping me progressing to the final stage!
Regards
Newbie7800
(http://www.audiocircle.com/image.php?id=101706)
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Hey Newbie!
Great to see the progress. Should be pretty easy to drill a 2nd hole in your board. Are you able to upload a pic of the board you are working with?
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Hi Matevana
Thanks for replying so quickly! Once the build is complete I will for the fun of it share all the trials and tribulations I had learning to build these things (including the last one which was a power drill I purchased for a hole saw to cut the tweeter holes which had a keyless chuck which was totally useless and would not hold the bit in place :-)) - just survived cutting the two tweeter holes. If I ever do another project again I have to learn how to cut tweeter holes with the router :-)).
The board is the same as what you suggested to get in the first place. It has the white circles on it and clear markings for L1, L2, C1 and C2. It is the same as the pictures of SJhomey (the red tall Hestia's :-) - I used the same measurements for my panels as you can see :-)). They have one hole per coil. I did not want to drill into the board without confirmation in case I was destroying any circuit :-). I really can't see how to do it with just one hole. Sjhomey has two cableties across the top coil in his pictures which looks nice and secure but this would surely need 3 extra holes drilled for the top coil (plus the one already there)
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Gotcha. Drilling the extra holes similar to what SJHomey did should be fine. I have also had good luck using heavy duty hook and loop tape (velcro) sold at Home Depot. One side adheres to the board and the other the bottom of the coil. You can then remove and reposition the coil as you need to. This works well if you didn't want to go the cable-ties route. It also keeps the coil from vibrating against the board (especially in cases where the board is attached to the baffle). I have also had to remove the velcro tape and it did not damage the coil or the board. Here's a picture of the stuff I'm referring to. If you are interested, Just be sure to get the heavy duty velcro, sold in tape rolls about 1.5" wide. You can cut it into a circle, just smaller than the coil bottom. If done right, you wont see it once the coil is mounted.
(http://www.audiocircle.com/image.php?id=101748)
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The MCM/Vifa top looks very good. I'm thinking of trying it with the 15" GSR in this design http://www.audiocircle.com/index.php?topic=99369.0
A 24" baffle width at the bottom tapering to 15" up top. This would raise the tweetr level up to ear level. Having to purchase the plate amps is a bit of a stumbling block but the flexibility they afford in integration is attractive.
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The vifa tweet is out of stock. Not due in until October now. Was thinking this one might work well;
http://www.parts-express.com/phenolic-ring-tweeter-8-ohm--270-252
People seem to like it's mellow sound and the price is in keeping with the design goals.
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I may have an extra pair of Vifa D19's. Either way, I would stick with a 3/4" dome for this design due to its dispersion characteristics.
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Mat - drop me a pm if you have a pair of the vifas.
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PM sent on Vifa D19's
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Going to give this design a whirl. That 10" mcm just has to sound impressive. Plan to do something different for the base driver though. Maybe a 12" woof in a Z frame that will also raise the ob portion up to ear level. I'll keep ya all posted.
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Hey Moto,
I got going OB with the original Hestia... a fantastic way to get into OB and test the waters with a small investment!! I have an extra pair of MCM's around new in box and used (like new condish but broken in). For the money you can't beat them and still listening to dual 10's below a Tang Band W4-1879 full-rangers at this time. Dedicated plate amps drive the dual MCM's and a Behringer DCX2496 for xover duties. A class D amp to drive the TB. I still can't believe how good this sounds.
As an option, I might have enough of the woofers to do 3 10's per side (dual for bass freqs). I think the transient response of small drivers like the dual 10's is an improvement over using a larger (with considerably more moving mass) 15" woofer. IMHO. 8)
Good luck with the build... if you have not done an OB yet to are in for a real treat!!!
Regards,
Rich
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Rich - I built a pair of John Busch's manzanitas so I have been exposed to ob. Hoping to bring more of the midrange out and the Hestia looks promising in that respect. I may be off base but I think the mcm should have the transients covered if it is rolling off down at 90. Initially I will just run the top and see how I like that before I integrate the base drivers.
Life is good when you are starting a speaker project!!!
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The Manzanitas, they were second on the list initially. Never heard them but surely sound nice.
Thats a good approach Moto... see how it sounds and go from there. And yeah... nothing like the start of a new build my friend!!!
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Baffle dimensions showing Right Panel (Left is mirror image)
(http://www.audiocircle.com/image.php?id=64841)
Dear Matevana and Hestia OB fan
Thank you very much for sharing this very interesting OB schematic because the baffle size is very suitable with my small listening room and I like OB sound.
Could I replace the mid speaker in your plan with Philips AD9710M/01 (alnico version)? I have these Philips speakers now and I love the mid range of them. In this case I dont need treble speakers any more because the Philips could manage quite well the HF in my own opinion. If Philips 9710 is ok, should I think of other woofer such as Eminence Alpha 12"?
How do this idea sound to you? Would I still get the optimal sound from your Hestia OB plan or will it change a lot when I use AD9710M/01 for the mid range?
I would appreciate any comment and suggestion from you.
Hieutl :)
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Hi Hieu-ma,
The original Hestia design is an easy build and fairly straight forward. The baffle size, driver selection and crossover components were all designed with the specific drivers in mind. That being said (and I am not familiar with the particular Philips driver you mention) changing even one component will likely impact the finished product. Part of the fun in experimenting with OB is the ability to easily create new baffles and try new things. Please let us know how the Philips midrange sounds in the Hestia design.
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Dear Matevana
Thanks for your guidance. I will keep searching for a suitable OB plan.
All best
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I have the mcm and vifa drivers in hand. The mcm driver sounds great with just the specified cap across it. I can tell it is going to sound like I had hoped. I'll keep you all posted as I progress with this design. First a quick mock up on mdf and then probably Baltic birch. If the results are stellar I may spring for some copper veneer.
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You have the added advantage of the original Vifa D19's made in Denmark. I think you are really going to like the combination!
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Matevena, I will be demoing the Hestia design at NY/NJ DIY in Brooklyn on Nov1.2014
Awhile back I posted about using the Dayton 15" instead of the 10" while keeping everything else
true to the original. I also loaded the 15" in an H frame. Finally finishing this project I started more
than 2yrs. ago. The Hestia Grande will make its debut, thanks for the design.
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Hey Squid,
My brother lives up in Brooklyn. Maybe I can have him check out the show. Can you post a picture of your completed project?
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Matavena, I will take some pics at the show. Info about the show is available on the PE Tech Talk
forum.
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Hey now! I've got one up and running. No bass driver yet so I've got the mcm driver running without the coil so it is making bass below 90. Very nice sound stage and midrange clarity. Amazing vifa tweet that can sound so good with such a simple filter. And considering I only have a cap across the mcm it is equally impressive. I strongly concur that driver selection is particularly critical for an open baffle system.
The mcm must be making bass into the 40's. This would be a good apartment speaker just the way it is. I will certainly be adding some kind of base driver on the floor below it though ( like to hear Phil Lesh drop live base bombs ). M - you did a splendid job with the Hestia. It is my kind speaker and I'm well pleased I decided to give it a try.
It will be awhile now before I finish this project. I will post pics when I do.
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Awesome! That just makes me wanna dig up some old Jerry Garcia stuff!
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Matevana, I am ready to build x-overs for this and found conflicting info ;page one you have
C1 and L1 going to the MCM mid/woofer and C2 and L2 going to the Vifa tweet, then on pg9
they are reversed. Which one is correct?
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Sorry Squid... didn't mean to confuse. The values on page one are indeed correct. C1 and L1, (7.5uf and 1.80 mH) respectively go with the MCM driver. The later diagram on Pp 9 was a generic attempt to show a close-up of the schematic; please disregard the labeling there.
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This looks fun. How sensitive is it? How far from the wall does it have to be? How good do you guys think it is?
Any thought on using the T26SG tweeter? It's pretty good and doesn't exceed price, but I dunno if it'd pair well.
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The T26SG is a nice tweeter but is far from a drop-in replacement. It is quite a bit more sensitive and has a different nominal impedance, so the x/o will need to be reworked. Sonically it is more detailed than the D19 but not quite as warm, based on my recollection. The D19 also has excellent off-axis response which is a hallmark of this design. If you are going to change the tweeter I would recommend either the Seas 19TFF1, the Vifa X19 or the Scanspeak D2008 which will all maintain the original characteristics of the Hestia design.
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Matevana, one more question. I am going to use the 300w Yung plate amp, I know you suggest that
all three drivers get wired normal polarity + and -. How about the phase control on the plate amp,
do I leave that at zero? Thanks Squid
P.S. is your brother going to see the Hestia Grande make it's debut in Brooklyn on Saturday?
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Hey Squid,
My experience with absolute polarity is that distance from the front wall (and other room boundaries) has an impact on phase relationships. If you experiment with placement you will see that standard polarity works best up to a certain distance from the wall, and when this distance is exceeded (by moving too close to the wall) reverse polarity can sometimes produce better results. You can measure this metric for specific frequencies and plot their phase relationships to see what's really going on, but it's often just as easy to do this by ear. The variable phase control (on some plate amps) allows you to dial this in (sorta) and can be interesting to experiment with.
Unfortunately my brother will be on the road this weekend. Please take pics and post them. I would really like to hear the comments about your entry.
Ed
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Well got everything assembled and wired; and wow. Trying to get them broken in for
the NY/NJ DIY event on SAT. So far incredible bass from the 15" woofer and crystal
clear mids/treb. I will let you know how they do at the big show. And pics of course.
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Well got everything assembled and wired; and wow. Trying to get them broken in for
the NY/NJ DIY event on SAT. So far incredible bass from the 15" woofer and crystal
clear mids/treb. I will let you know how they do at the big show. And pics of course.
Will you/they be in the shop tomorrow?
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Hi Matevana
I have 4 of these 12"
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2962-/55-2962
Can use it as mid?
The big difference is sensitivity.
What you think.
Thanks.
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Hi Matevana
I have 4 of these 12"
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2962-/55-2962
Can use it as mid?
The big difference is sensitivity.
What you think.
Thanks.
Honestly you can try. I suspect that since you are are trying to meet a 3/4" dome you will be asking the 12" driver to play out of it's comfort zone; the mids may suffer a bit. The sensitivity issue can be dealt with easy enough.
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Hi Matevana
I have 4 of these 12"
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2962-/55-2962
Can use it as mid?
The big difference is sensitivity.
What you think.
Thanks.
Oh Zaa, how about using those 12's for bass duties driven by plate amps and keep the 10 and Vifa up top as designed. That would be a wonderful use of your MCMs!
Cheers,
Richard
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Thanks
I already have 4 (12)
Would use as mid and bass drivers.
I am goin to buy Vifa and crossover parts to try how it sounds.
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Hi all, pictures and reviews of my Hestia project at the NY/NJ diy event can
be seen on the PE tech talk forum. If anyone could post them here I would
appreciate it. I'm computer challenged
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Will you/they be in the shop tomorrow?
How would you like to listen to them for a couple days at home, these don't have a home yet
so If you want to try them out let me know.
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Yeah man would love to have them in the system for a cuppala days. :D
(http://www.audiocircle.com/image.php?id=108081)
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Hey all, new to the board, but not audio. I've been a DIY'er most of my life and just love it! I've been following this for a few months and have a couple of questions for Matevana and those who've heard/built these before I start this project.
I noticed Matevana, that you're a musician; I'm a drummer...the guy that follows y'all around ;) and am looking for a nice set of OB's that give me that concussion that drums produce, mostly the snare, while being clear in vocals and maintaining exceptional transient responses. So question: will these produce that? My gut says yea, but...
I currently use Magnepan 1.6/QR's with a Crown DSi 100 amp and custom subs and while the maggies sound beautiful, they lack that "kick". I'm not looking to blow the doors down, but I miss the dynamics that I KNOW are there. I truly listen to everything except rap, mostly focusing on country/classic rock.
Thanks for the help guys, Brad
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Hey Brad,
Thanks for your interest; it's a really addictive hobby. You ask a really good question that relates to feeling the whack of a snare as opposed to just hearing it. Dipoles do a great job of producing sounds accurately and have a speed to them that as a drummer, you will really appreciate. In the near field (when you sit close to the speaker pair at the apex of an equilateral triangle) you will also feel the music in your gut. What dipoles don't necessarily do (by design) is load the room, which is unfortunately how most people are accustomed to hearing traditional boxed speakers. That being said, given the proper drivers and power, they can energize you to the point where you feel the music as well!
A good example of this is a dipole project by Martin J King which makes use of two AE15 drivers per side for bass duties. I have not heard these myself, but based on Martin's description may be something you would like to emulate in your design. Martin comments on how little driver movement occurs when a total of 4, fairly efficient, 15" drivers are used. Regardless, all true dipoles will produce the figure of eight radiation pattern,which depending on where you sit, will tremendously affect how you hear and feel the music.
Ed
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Ed, thanks for the heads up on this. I considered the Hawthorne 15" Duets much for this reason, but I'd like a smaller footprint (and price tag) than they have, hence looking at DIY 10's. Your design hit me just right; it wasn't too large, too costly and everyone had done so much development it seemed like a no brainer. I don't have a workshop anymore (traded a back yard shop for a river :wink:) so a lot of trial and error is just not viable. I guess I'll keep looking.
If any of you guys have seen a design using 10's like this one that may meet my goals of a solid punch, clean sound all round and OB, please point me in the right direction. I'd be most grateful. No matter what, thanks for taking the time to help me out!
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You might want to check with Squid since he uses a larger bass driver with a similar footprint. It isn't that they don't go low enough or get loud enough... they do. It's the way they interact with the room that's different. Picture your drum set in a recording studio with foam on the walls and ceiling. Your kit would sound very articulate and uncolored... not what you would expect in a club or live setting.
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Squid OB at Casa De Rodge :D
(http://www.audiocircle.com/image.php?id=108222)
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Ed, thanks for the heads up on this. I considered the Hawthorne 15" Duets much for this reason, but I'd like a smaller footprint (and price tag) than they have, hence looking at DIY 10's. Your design hit me just right; it wasn't too large, too costly and everyone had done so much development it seemed like a no brainer. I don't have a workshop anymore (traded a back yard shop for a river :wink:) so a lot of trial and error is just not viable. I guess I'll keep looking.
If any of you guys have seen a design using 10's like this one that may meet my goals of a solid punch, clean sound all round and OB, please point me in the right direction. I'd be most grateful. No matter what, thanks for taking the time to help me out!
Brad... dude... go with dual MCM 10's and a plate amp per channel (look for sales over the holidays). I have a pair of Jung 200 watt with 6db boost and they drive the MCM's flat to 35Hz with lots of snap. I like smaller, faster drivers for better transients and for such a inexpensive woofer the MCM's are amazing. I have a small room and needed a narrow panel and these have worked very well for me.
I went with the Tang Band W4-1879 on top instead of the MCM and the Vifa's as I really enjoy the coherency of fullrange drivers. But I'm sure the MCM 10 + Vifa as per the design would sound excellent as well.
Build with confidence... you will not be disappointed!!
Cheers,
Rich
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Squid OB at Casa De Rodge :D
(http://www.audiocircle.com/image.php?id=108222)
How do they sound?
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You might want to check with Squid since he uses a larger bass driver with a similar footprint. It isn't that they don't go low enough or get loud enough... they do. It's the way they interact with the room that's different. Picture your drum set in a recording studio with foam on the walls and ceiling. Your kit would sound very articulate and uncolored... not what you would expect in a club or live setting.
OB speakers work in smaller rooms for the reasons mat mentions above. I set my manzanitas up in the mouth of a 2 car garage and they sounded fabulous. The music just plain enveloped the scene. So they work well in larger spaces too provided enough clean amplification.
(http://www.audiocircle.com/image.php?id=108451)
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Nice pic Moto!
How are the Hestia's sound after the drivers are broken in? I noticed a large improvement in the MCM after about 100 hours of break-in. Interesting that the sounds good even without lower bass support. They look nice man... nice work!
Regards,
Richard
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The MCM/Vifa combo sounds sweet. The MCM is quite revealing, less forgiving of poor recordings than my other speakers. The increase in detail is what I was hoping for so I'm well pleased thus far. Life is too short to bother with marginal recordings.
The upper half of the Hestia in the pic is just a test setup. I've been running one Manzanita for the base and the sound is very good. I'm leaning towards the GRS 15" for the base duties, perhaps in a flat baffle that is 24" wide at the base and 14" at the top with the taper on one side. 40" total height.
I'm pausing at this point while I dope out the bi amping issues. My preamp has two separate outputs, one being adjustable. Been looking at a 1875 chip amp for the top and my current class d amp for the base. Would handle the crossover at line level with filters as Mat has done recently. It would be simpler to just go with a plate sub amplifier and I may go that route if I get impatient.
Mat's work mating the MCM to the Vifa is really the heart of the system.
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Hey Moto!
Glad your enjoying the top of the Hestia! I heard the GRS are nice in OB! I went all MCM with dual 10's on the bottom for better detail and transient response (and a more narrow panel for my small room)... I like smaller drivers but most folks go with 15's or even 18's but I've found the dual 10's perform very well in my listening room... way more than I really need actually.
Cheers!
Rich
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Guys, thanks for the advice! :thumb: I'm looking at OB Newbie's idea of dual 10's merely for SPL or something similar using Visaton WS25's, Typmphany horn tweet and a 12" sealed sub. I don't want to hijack this thread, but if you guys have any advice, I stuck up the question on a new post.
On that note, what are the crossover points for the Hestia? I'm crosseyed from scanning posts.
Can't wait to start this endeavor and FULLY join the OB club! :green: Thanks again!!
Brad
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Brad - The crossover between the mcm and vifa tweet is not really specified but the two LR2 filters work nicely. The bass driver starts coming on at 90hz where the mcm mid begins rolling off on the ob naturally. Pretty elegant use of the driver's curves all in all.
I'm sticking with the flat panel for asthetic reasons and may go with two 10" base drivers per side to raise the tweet to ear level and to keep the system from getting overly wide. I think the original design would satisfy most people but us diy folks can't seem to leave well enough alone. Have fun!!!
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The inductors are Jantzen 18 AWG air core and the Caps are Dayton Audio Polypropylene. I use the Dayton pre etched 2-way PC board number 260-130 which makes a nice finished product. I typically mount them on the baffle back with rubber washers.
L1 = 1.80 mh 18 AWG
C1 = 7.5 uf
L2 = 1.40 mh 18 AWG
C2 = 5.6 uf
(http://www.audiocircle.com/image.php?id=64935)
(http://www.audiocircle.com/image.php?id=64936)
Hey Brad,
Above is the X-over schematic for the original design. Honestly, I would stay with the MCM + Vifa top as is. Then run plat amps for the helper woofers. Its the helper woofers that allows you a little flexibility to add your own touch. A single 15... dual 10's or 12's... kinda depends on what you want for a baffle size and of course your own preferences for good bass characteristics such as speed, attack, extension, power handling.output, etc., etc.
Have fun with your build and check in with any questions. Can't wait to hear the progress.
Cheers!
Rich
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Brad - I noticed that 10" Visiton driver as being particularly siutable for ob. Price is right too at under $30. Perhaps you noticed on one of Matevena's newer designs that he is using line level filters to blend the bass into the midrange in place of a dedicated plate amp. This looks attractive to me because I've heard that relieving the mid driver of frequencies below say 100 hz or so improves the midrange response. Of course you need another amp to accomplish this but you could choose one that excells in mids and highs, like a 1875 chip amp for example.
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Slowest build in history update pic. Crossovers built for xt19 and mcm combo. Perhaps will be finished at Christmas....
Newbie
(http://www.audiocircle.com/image.php?id=109201)
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Congrats Newbie! Let us know how you progress over the holidays... looking for forward to you getting some OB sound!!!
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Well after much internal debate, I ordered up 4 MCM's and 2 of the Vifa XT19TD00-04 tweets with adjusted caps and coils to match the impedance. I plan on using one MCM with a plate for bass duties and one for mids with a sealed 12" JBL sub in a 2 ft3 enclosure for sub duties. I'll likely start the journey this week and will post pics for your amusement.
Thanks again for the guidance Matevana, moto and the newbies. Much appreciated :thumb:
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Niice! Looks like Christmas may come early this year?
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Receive cross parts from Newbie, thanks man :thumb:
I would go with 2ea speaker - 12" MCM for LF.
Questions:
1- I have 1 Dayton 225 plate amp, would use initially for test to drive the 2 speaker. Would SQ suffer. ? How?
2- Want to go narrow. 16" wide baffle vs 18". Would be a significant difference between 16-18"?
3- Want to use 12-14ga bare solid cooper wire for LF driver back connection (just for looks) would this affect in some way?
(http://www.audiocircle.com/image.php?id=109911)
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Receive cross parts from Newbie, thanks man :thumb:
I would go with 2ea speaker - 12" MCM for LF.
Questions:
1- I have 1 Dayton 225 plate amp, would use initially for test to drive the 2 speaker. Would SQ suffer. ? How?
2- Want to go narrow. 16" wide baffle vs 18". Would be a significant difference between 16-18"?
3- Want to use 12-14ga bare solid cooper wire for LF driver back connection (just for looks) would this affect in some way?
(http://www.audiocircle.com/image.php?id=109911)
Glad you got it Javi and ready for the build man!
1. Ed's original design had a single plate amp driving the helper woofer crossed at 90 Hz or so I think... I'd read the beginning of the thread. There isn't much stereo information in the very low frequencies so no problems if you keep the xover freq. low.
2. 16 is perfectly fine. The original design was slightly less than 16" if I remember right.
3. Solid copper sounds great to me. Fast and detailed but can sound thin... though my expirience was 18 awg (forgot to tell you than via PM) so not sure if 12-14 awg will sound thin and need doubling up.
Cheers!
Rich
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Hey Piazza,
Rich was right on the money in his responses. If you're referring to solid conductor copper as opposed to stranded copper, you should be fine. It is somewhat less flexible (particularly in the thicker gauges) so it may not lay right across the floor but should sound fine. One of the better wires I've heard has been bare copper ground wire, encased in either vintage cotton or Teflon sheathing using air as the insulator. I would just stay away from copper coated aluminum wire, which can sound pretty awful IMO.
Ed
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Guys, a quick question here...this xover is a LR 2nd order, right. Shouldn't the tweeter be wired out of phase with the woofer? I'm sure it's been addressed but I couldn't find it. Thanks in advance, Brad
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Guys, a quick question here...this xover is a LR 2nd order, right. Shouldn't the tweeter be wired out of phase with the woofer? I'm sure it's been addressed but I couldn't find it. Thanks in advance, Brad
Brad. Generally speaking, in a purely 2nd order electrical circuit you would be correct. But you have to look at the summed acoustical response as well. If you build the crossover as spec'd but try reverse polarity, you would likely hear that they do not sum properly. I remember a loss of coherence with cymbals, etc. when the tweeter was reversed. Very few topologies work-out to be textbook and it pays to try them both ways. Go with the one that measures (sounds) best.
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Ed, thanks so much for that! I read thru your early design notes and thought I remembered you saying something about not using standard wiring. Perfect!! I have all the baffles cut and need some finish work done. Pretty amped!
(http://www.audiocircle.com/image.php?id=110071)
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One more step guys. Even though I only have a plywood baffle I wanted to use this project to learn some skills. So I spent Saturday (took a good few hours) to do the recess for all drivers, not just the tweeters. I used a rabbet bit but unfortunately only had 12.7mm as the maximum so had to do some sanding to fit the MCM. I am about 1mm off on all the drivers after a test fit. I was wondering, how does everyone screw in the drivers. I have the baffles balanced between two cardboard boxed and I am dropping in the drivers through the holes but it is not easy, kind of need 4 hands to do this properly.
A question on the RCA plug filter used for the bass driver - where do I put these exactly in my wiring. Is it for the preamplifier out towards the plate amp??? This would act as a filter from the preamp to the plateamp. Assuming this is correct?
Thanks for all your help. Almost in touching distance to getting this project finished!!!
Newbie
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Ed, thanks so much for that! I read thru your early design notes and thought I remembered you saying something about not using standard wiring. Perfect!! I have all the baffles cut and need some finish work done. Pretty amped!
(http://www.audiocircle.com/image.php?id=110071)
That looks great Brad! You have to let us know your thoughts when you begin testing.
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A question on the RCA plug filter used for the bass driver - where do I put these exactly in my wiring. Is it for the preamplifier out towards the plate amp??? This would act as a filter from the preamp to the plateamp. Assuming this is correct?
Newbie
If you are building one of the original Hestias and are using a plate amp with a built-in crossover, you will not need to use an F-Mod (passive inline crossover). If your plate amp doesn't have an on board crossover, you can attach the F-mod directly to the input on the plate amp.
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Matevana
Thanks as ever...yes building the original hestia as of November 2012 :D
Whoops I did not realise the fmod was for another hestia build...I have the original plate amp you recommended and which sjhomey also got. It has an active cross over. So I have no purpose for the fmod.
I am 1 day away from completing the build.thanks again for all your support.
Newbie
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Excellent! It's funny how so many original Hestia builds are taking place now. If I could only get someone to try a V! :D
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Well not quite original ;-)...you got me on page 2 or 3 of the thread onto the idea of using the Xt19...so I am building one of your modified babies :-) with your suggested amended crossover changes. Let us see how the XT19 ends up sounding.
Just before Christmas I should get the 1 day space I need to finish the project and if the thing works then pics will be on the way :-). I really can't wait to hear the OB sound for the first time!!!! Assuming I did not screw up the crossover wiring ;-).
Newbie
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A really quick way to test your crossover w/o fear of harming the XT19 would be to use the same MCM woofer to test the low side and the high side of the crossover independently. When hooked to the high side you should hear a complete absence of bass. If you hear either full range or low frequencies only, something is wired incorrectly. If all is good, you can then safely substitute the XT19.
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Thanks for the tip, will do.
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Hey Ed,
I gotta say a big thanks to you for thinking of this little system, putting in the time to test/refine it and then putting out all the info. Kudos my friend!!!
I started burning in my drivers last nite (triamped since I haven't finished the crossovers) and so far I like what I hear. I played one channel with my MG 1.6Q/R Maggies and the other with my version of the Hestias and while the clarity wasn't quite there (due mostly to drivers not yet being broken in I'm sure) compared to the Maggies, the weight and overall experience/sound was SUPER promising...and at 1/10th the price!! :thumb: I enjoyed the dipole nature of the sound and the apparent ease of low-mid range reproduction. I can't wait to hear them after 100 or so hours.
I'll be away for a while...actually in your neck o' the woods, but will post pics of progress and the final products. Ya gotta be one proud papa!
Take care,
Brad
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Brad,
Thanks for the kind words and I'm glad you like what you hear. They will only get better over time, and like the Maggies, you will find that every small change you might make will affect them... and hopefully in a positive way!
If you are going to be anywhere near South Florida (I'm between Ft Lauderdale and West Palm Beach) let me know... I would be glad to demo the Hestia V's and the Hestia V Domes for you!
Keep us posted.
Ed
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Ed,
I was right there at The Breakers for a holiday party and visiting friends...wish I woulda looked at the forum! :roll:
Anyway, I got back Sat and spent several hours tweaking and got them sounding pretty good! I did end up making a few changes though. I low passed the 12" sealed subs (my version) thru their plate amp at 90Hz, the MCM 10" "bass helper" ended up band passed from 50-250Hz via the amp DSP and the MCM/Vifa combo hi passed from 325Hz out via the amp DSP; employing the passive W/T network of course. All said n done, there it is! The "oomph" from dynamics that I wanted with an overall smooth sounding response. My wife actually commented (unprovoked) that they sounded more full and realistic to her than the Maggies...more like live music. The unbiased ear is always a good litmus test :thumb: On that note, anyone want some MG1.6Q/R's and MGMC1's?
I've been out of DIY for a while and have missed it! This has been a great experience. Now to find a paint n body shop to spray these for me and I'm DONE....well at least til next time! Thinkin a center channel may be due. :green: I'll stick up some progress pics soon.
Brad
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Good go'in Brad! Yes, please post pics when you can. I wish I could agree with you that after paint you're DONE. It's been my experience that this is where the obsession truly begins. In fact, I'd like to coin the phrase that one good OB session = OBsession, lol. I'm considering selling a kidney to fund my next project. I may even call it "OBsession". :o
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Yea, being done is a dream...that order will be delivered by a unicorn riding leprechaun! :wink: OBsession would be a great name for an all out speaker, Ed. Great idea!
So I finally got the project up and running (not done, right Ed) and am enjoying it a lot! My 16 year old son was listening with me as we compared these with the 1.6's (still for sale BTW) and he liked them a lot more. We auditioned several discs and DVD's. Now bear in mind I know 16 year old ears are not truly qualified to judge, but it was a good bonding moment and experience as he has been helping me out. I did make a few mistakes painting them that I will address next year, but for now, I'm ready to get fat and listen to these things...it's the holidays!! :green: Anyway here are a few pics. Merry Christmas and Happy Holidays you guys!!
(http://www.audiocircle.com/image.php?id=111062)
(http://www.audiocircle.com/image.php?id=111063)
(http://www.audiocircle.com/image.php?id=111064)
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Nice ...! :thumb:
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Nice job Brad! They look fantastic!!!
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Sweet! :D
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Happy holidays !!!
(http://www.audiocircle.com/image.php?id=111126)
First listening. Ummmmm...
Thanks Matevana.
Thanks Newbie
Unfinished but playing, Santa cant wait...
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(http://www.audiocircle.com/image.php?id=111129)
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Very cool! Really like the way the design came together. Is that 1" MDF? What are you using for speaker wire?
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What a beautiful, modern look! Very nice work.
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Very cool! Really like the way the design came together. Is that 1" MDF? What are you using for speaker wire?
Hi Matevana.
Wood is Virola panel 5/8 (sandwich 2 gave me almost 1 1/4 thick)
Cables are Cat 5 with snake oil fermented :green:
Not finished, maybe white Duratex.
Cross are going to be concealed.
First OB design listening. They are very open...
Would give my review in a few weeks, so far, are goooooood.
Matevana thanks for sharing this desing... :thumb:
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Javi!!! Awesome man... well done! White duratex would look flippin' fantastic! Can't wait to see them finished.. looking forward!
Happy holidays to all!
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Dear Matevana, Dear Hestia OB owners
Well I finished the build but I think without success. Being so sure I had wired the Crossover correctly (for the XT19) I plugged everything in and off I went (sorry should have slowed down). Anyway the sound was not too bad but the Xt19 have what sounds like distortion after a certain volume level.
I studied the various crossover postings numerous times before building the cross over but my complete lack of electronics knowledge is probably getting in my way. I have attached some pictures to see if anyone can help. Because of C1 and L1 in Matevana's design being for the MCM driver I thought that the plus connection labelled +T must be for the MCM and that the +W must be for the XT19. L2 and C2 are soldered to the +W connection (being 0.70 coil and a 12UF cap for C2).
I am lost as to what I have done wrong. Any help to make my Christmas better would be great. I have waited 2 years for this moment and now feel a bit deflated. I hope I have not ruined the Xt19s in the process but luckily they are not too expensive if I have.
Thanks in advance for your collective help!!!
newbie7800
(http://www.audiocircle.com/image.php?id=111432)
(http://www.audiocircle.com/image.php?id=111433)
(http://www.audiocircle.com/image.php?id=111434)
(http://www.audiocircle.com/image.php?id=111435)
(http://www.audiocircle.com/image.php?id=111436)
(http://www.audiocircle.com/image.php?id=111437)
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If I have wired the crossover correctly, which I am starting to doubt, I wonder if this article might explain my issue with the XT19.
http://www.rjbaudio.com/Audiofiles/faulty%20XT19.html
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Newbie,
It's hard to trace the wires from the pictures you provided, but based on the following description you gave:
"I studied the various crossover postings numerous times before building the cross over but my complete lack of electronics knowledge is probably getting in my way. I have attached some pictures to see if anyone can help. Because of C1 and L1 in Matevana's design being for the MCM driver I thought that the plus connection labelled +T must be for the MCM and that the +W must be for the XT19. L2 and C2 are soldered to the +W connection (being 0.70 coil and a 12UF cap for C2)."
it is likely you have the low and high circuits going to the wrong drivers. In circuit board nomenclature, T+ indicates the positive side of the tweeter, W+ the positive side of the woofer. Based on the way you described how it sounds, the tweeter is getting the signal intended for the woofer (and vice versa) which would cause the tweeter to distort badly at all but the lowest of volume settings. Be careful here as you can easily damage the tweeters (but not the woofers) if you are driving them with a low frequency signal.
You can test this using only the woofer, as you will not damage it by feeding it either signal. Disconnect the tweeter entirely and work only with the woofer for now. First listen to the woofer the way you have it hooked up. You should hear mostly lower sounds with muted highs. Now disconnect the woofer and connect it to the leads that were formerly connected to the tweeter. Now you should hear a complete lack of bass through the woofer, with only high notes present. If you hear the opposite, you have the low/high circuits backward. The easy fix here would be to simply disregard what the circuit board says (since you have already soldered the components) and feed the drivers in the opposite orientation as to what you currently have. (You may need to adjust the length of the leads to reach the proper driver).
If you are completely stumped, I would be glad to look-at and fix the crossover for you. You can mail them to me, I will redo one and you can follow what I have done for the 2nd after I mail it back. I realize that isn't as immediate, but I'll throw that out since I know you must be frustrated!
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Hi Matevana
Thanks for the reply. If you look at the drawing this is how I wired the crossover. L1 and C1 as per your original instructions are for the mcm. However on the parts xpress board they are wired to the T+. Since L1 and C1 were for the MCM I thought regardless of what was on the board I should follow your picture showing L1 and C1 connecting to mcm. I tried before connecting the mcm driver to both outputs and the sound I got was muffled bass sound......
Looking at my drawing should the tweeter be connected to t+ even when L1 and C1 connect to it. This is what completely baffles me...
The distortion is also not even with 1 tweeter making more tHan the ever..
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Hey Newbie,
L1 stands for inductor #1 and c1 capacitor #1 and are used to indicate the values of those components. They have little to do with the positions of the components that get inserted into the pre printed circuit board. The relationship of the two components is inverted for the woofer and tweeter, with the woofer circuit having the inductor in series and the capacitor in parallel, and the tweeter having the capacitor in series and the inductor is parallel. The circuit board does this orientation for you if you follow the wiring for the positive and negative terminals for the woofer and tweeter. In other words, the MCM gets wired to W+ for the positive and the Vifa goes to T+ for it's positive terminal. Without seeing the board up close it sounds like you have them reversed? It's hard to tell for sure in the picture since you have the same color combinations going to both the MCM and the Vifa, and they are coiled making a trace by eye too difficult from the photo.
Also, I noticed that the inductor mounted on it's side is about half the size as what is spec'd, so I'm guessing you made the adjustment for the 4ohm XT19 as opposed to the 8 ohm D19. If that's true, you definitely have the components soldered into the wrong positions, as that would be the slot intended for the woofer's inductor and not the tweeter. I'm hoping that makes some sense.
If it's easier to discuss this I can make my phone # available to you if you PM me.
Ed
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On the parts xpress board I followed the sheet that came with it and placed each if the coils and caps as per the instructions. However as I saw the L1 and C1 caps connecting to the same pad as the t+ this confused me as i thought it was like a pcb and could not figure out why L1 and c1 would have solder points on the same pad as t+. Dumm for those who understand the pre etched board but confusing for me.
Yes I did follow your instructions for x19 and at the top have 0.7 coil and 12 cap which link to w+ but I connected the tweeter plus there thinking the coil and cap connecting to the w+ pad where meant to be for the tweeter.
Will pm you in the morning. Thanks again.
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Hey Newbie, first off...nice work :thumb: I hope ya have gotten it resolved.
If not, I looked over the pics and unless my eyes mixed the wires/diagrams, they are indeed reversed. Just remember in the high pass section of a crossover (regardless of slope) the cap is the first reactive device the signal will encounter; the low pass will be an inductor. Unfortunately ou will have to swap over all the components on the board to work. C1 will be the 12uf cap, L1 will be the .7mH coil; T+ will go to the Vifa's + term. C2 will be the 7.5uf cap, L1 will be the 1.8mH coil; W+ will go to the MCM + term. I'm using the XT19, too BTW and they work great.
Also, at first this set up did not sound great...in my opinion; good, not great. It took a few of weeks of many hours of just letting the speakers play to break them in. I made several adjustments to active crossover points and equalization all to have them sound like crap in the next listening session. Lesson here: patience grasshopper. I ended up pretty close to what Ed described: 20-90 Hz for 12" sub, 90-280 Hz for 10" MCM and 125-20,000 Hz for the MCM Vifa pair. Now they sound pretty darned good to me! I'm quite happy all the way around, as I'm sure you will be once you get the wiring woes resolved and the drivers settle in.
Best of luck bud!
Brad
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Dear Ed, Brad and SJHomey
First the good news...everything is working and sounding pretty darn good. A lesson for any beginner is to ignore completely the parts xpress labelling of the cross-over components and actually look at Ed's original drawing of the crossover circuit. Thanks to Ed for taking the extra time to talk me through this. 2 years of waiting and I am officially part of the Hestia OB family. I want to thank Ed and also SJHomey for their support and various posts going back 2 years even for the smallest of details like what were good screws to use. Also for SJHomey's idea to place the vifa/MCM drivers higher. Completing this project from Germany has not been easy but I am completely satisfied.
I cannot be sure I did not damage the XT19 in the process. I played a few tracks on my headphones and then through the speakers and could not hear any "damage" but the XT19s excursion was crazy for a while when I had them connected incorrectly although luckily I turned them down when I heard the distortion originally. I may end up replacing them in a few months to end my paranoia.
I want to thank Brad also for his last post. I am very pleased even with the XT19 in its post abuse state. Detail levels are very pleasing. I have played them as much as I can the last few days.
I want to find a solution for protecting the back of the drivers. I have temporarily used grill cloth to cover the backs. Sound is a little muffled so will work on quick remove back covers with velcro so for proper listening I can listen with the backs uncovered but for day to day use I will keep the covers on to protect the drivers from being poked, dust etc...
Couple of questions:
For the plate amp (Yung SD300-6 300W) - I wired the positives and negatives of both Left and Right driver to the red and black lead from the Yung plate amp (model is the 400. Assume this is correct. I would be interested to know what position people using this amp have the cross-over and the level. The scale of the crossover starts at 40hz and goes to 200hz but not sure where the 90hz position is. I have it just before the half way point. The level I have at the first dot above minimum. I have neighbours downstairs :-).
Also, what is the maximum space between the speakers in feet and what about the level of toe in. Any recommendations from listening experience would be great.
Finally and most importantly, the Hestia OBs sound have also achieved WAF :-)
Newbie
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Hey Newbie,
In all the discussion over the wiring, I neglected to compliment you on your build. I really like the appearance as well as your interpretation of the design. Nicely done!
I no longer own the original configuration so I cant comment on the Yung's settings. Generally 1M or greater from any room boundary is appropriate, but people have placed them closer as necessary. I had them toe'd-in so they crossed about 1-2 feet ahead of the listening position. I found that provided the best imaging, if memory serves.
Regarding the tweets, if the VC's were blown the distortion would be obvious. It is likely they came out of it unscathed!
Ed
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Hello
I'm going to finely start on this project but I need a pair of tweeters. Would the XT19 be worth the extra $ over the D19? I have all the other drivers and the inductors (.70mh) for using the XT19 however if I buy the D19 I will need buy a pair of 1.40mh... :roll:
Thanks
Frank
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Bear,
I wish I could help with a direct comparison, but I've only used the XT-19. I'm quite happy with it all around. I will caveat that you MAY want to add a PAD inline. I was contemplating it as the tweet will inherently be a bit louder since it's 4 ohm and getting more power. I eventually went fully active with DSP...I know it's cheating, but what a difference it makes to be able to tailor everything to your surroundings and taste...NOT that Ed's taste is bad. I don't want to get a beat down from the maestro here!! :o
For those interested, I completed a little modding on my version of the Hestias this weekend. I did a LOT of soul searching and researching, but eventually removed the dustcaps, built and inserted a phase plug in the pole piece. I know that you usually hear an improvement proportional to the amount of work invested, but I gotta say the plugs, pole extensions, whatever, really cleared up the overall sound of the speakers and I now am crossing them from 105 Hz to 4KHz with LR4 slopes and using a low Q, 10 dB notch at 575Hz to get rid of the inherent "honk" or beaming from the 10's. The XT19's are crossed at 1.6K and blend nicely. I just did this this weekend and am still tinkering. I'll stick up a pic when I can.
Once again, thanks to all you guys and especially Ed for putting this together. I love this stuff!!!
Brad
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Frank,
I'd be tempted to try a single high quality cap (1.5 - 2.0 uf) with the XT-19 and omit the choke. Where tweets are concerned, inductors can be :evil:. Go with a Mundorf Supreme or something comparable. As Brad mentions, you may need to level match. The XT-19 used in the Hestia V Dome sounds great.
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Hi Hestia OBers :-)
Couple of comments.
Brad - would you mind explaining how you carried out the dust cap mod. Just on the MCMs was it? Would welcome details. Would also love to understand how you implemented the active cross over.
All - I am having a problem with vibration. I built the taller version (as did SJHOMEY). The baffle is ply and thickness is as per Matevana's original design. Any clever tips to reduce. I am also getting little volume control from the bass plate amp. It just is too powerful...
BR
newbie
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Newbie,
If you look at the original proportions of the Hestia design, you can see that the baffle does not extend out more than 25% of the drivers diameter at any point. The design relied (in part) on the rigidity of the driver's frames to help prevent baffle flex. That being said, two things come to mind which may help with the modifications you have made. The first involves increasing rigidity; the second vibration damping.
Aside from increasing baffle thickness, some have had good luck by coupling rigid "C" or "L" channel down the back of the baffle. (Think industrial wide shelving standards). Try to run the C-channel on the diagonal to some extent (avoid running completely parallel to the baffle edge) as this will counter a greater degree of lateral flex.
Still others have had luck eliminating buzz by damping the backs of their existing baffles. There are recipes for DIY damping compounds online that contain tile mastic and granulated rubber (like rubber mulch but finer). The compound is troweled onto the back of the baffle with a v-notch trowel and allowed to dry. Some have used alternating layers of the DIY compound along with roofing felt to create a sandwich effect. Haven't tried this with any baffle (haven't needed to) but the concept is interesting.
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Hey Newbie,
My solution was, as Ed said, double panel thickness; 1-1/2" thick when finished. The baffle sides also widen as you get closer to the floor. You may want to try a "T" type brace down the back like in the Jamo & Linkwitz speakers. I'll likely do this soon as I'm getting some vibration from the sub (which is attached) in the upper sections.
The dustcap mod was a little spooky and you will likely tear some of the top fibers leaving a ring where the cap was. No real harm though. If that doesn't bother you, then what I did was cut an "X" in the face of the cap from the center out to the edges giving you 4 "pieces of dustcap pie". Then gently and slightly lift the corners of the area glued to the cone and SLOWLY work the X-acto knife around the circumference cutting as closely as possible to the cone. I built the "phase plugs" from discs of wood cut using a 1-3/4" hole saw for the insert in the pole vent and a 2-1/8" for the remaining 3 discs. I then glued them together, ran a 1/4"x4" bolt through the pilot hole, squeezed it all together with a nut and formed the final point rotating against an angled table saw blade. This will make most shop class instructors cringe, so be safe!
The pole piece vent is EXACTLY 1-1/2" in diameter, so a dowel cut to 3/4" deep is also viable.
That was a couple of weeks ago and now something else...still using the (4) MCM 10's but now using (4) Vifa OT19NC00-04 3/4" Fabric Dome Tweeters per speaker in a coaxial design. I attached a pic if you're interested. I prefer this set-up personally and am still tinkering. What this brings to the table is better off axis response and broader soundstage with great imaging. BTW, I listen primarily to music and even watch movies in 2.0.
As for the active crossovers and eq'ing, I use 2 Crown CDI-1000 amps with DSP; one for mids one for highs and a Behringer iNuke 1000 DSP for subs. The Behringer needs a fan mod right away, but for $200 ya can't beat it. I am finding that these open baffles REALLY open up with DSP...there's a little known guy with the initials SL that uses it extensively. It is cheating, but I don't have time or money for the test gear or to buy and store all the LCR components it would take to do a passive system correctly. If you are asking about cross points and equalization, that's lengthy and I'm still playing around with it. You'll need different values for different environments so there's no substitute for experimenting.
Hope this answers your questions and helps,
Brad
(http://www.audiocircle.com/image.php?id=116035)
(http://www.audiocircle.com/image.php?id=116036)
(http://www.audiocircle.com/image.php?id=116037)
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I think it was AC member PoultryGeist who came up with the idea for using wooden eggs found at craft stores as phase plugs. He put two (or 4) screws in the base and the "plug" was then held in place magnetically by the driver's own magnet, after performing the dustcap-ectomy procedure described above.
(http://www.audiocircle.com/image.php?id=116040)
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Yea, I saw that. I didn't realize he did it on the MCM's...that woulda save me a LOT of fabricating! :duh:
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LOL, yeah, you were busy! But you got those nifty point source drivers to show for it.
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Indeed! The wife threatened taking the boat out without me...THAT was all it took to simmer down on the speaker hobby :o
I think at this point that I'm cluttering this thread with all the changes I made to the original Hestia; the only shared component is the MCM 10's. So if anyone else has questions on my set up, PM me or I'll be glad to start a new thread. :thumb:
Ed, thanks again for doing the legwork to select the drivers and all the design work! Truly a great intro to OB and it was actually you that warned back in December that I'd never be truly done... :green:
Take care guys,
Brad
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Feel free to continue Brad! I no longer own the original Hestia's so if it weren't for people like you there would be little activity here, lol. Besides, seeing the evolution has been fun for me.
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You guys are amazing. Lots of info here. Will digest and come back to you and keep posting Brad. The evolution/tweaks are always interesting :D
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Finely got my done and I really like them... thank you for all the help!
(http://www.audiocircle.com/image.php?id=123617)
(http://www.audiocircle.com/image.php?id=123618)
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Very cool. What do you think of the XT-19?
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I like it and for the money it's really good.
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I'm tempted to build the top two thirds of this design and place it over my MLK spec'd 18" Goldwood H-Frames. Has anyone else experimented with this setup?
I have separate amps for the H-frames and the tops (currently hosting an 8" full ranger) and my main concern is a greater distance from tweeter (ear level) and the center of the 18"s. Is this concern justified?
Thanks in advance!
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I'm tempted to build the top two thirds of this design and place it over my MLK spec'd 18" Goldwood H-Frames. Has anyone else experimented with this setup?
I'm in the process of redesigning the crossover to wind up with a lower component count; working with the resistance of select caps and coils to eliminate separate resistors for level matching. This also necessitated a woofer change to the Peerless SLS line for the top section's lower midrange duties. The total component count will now be one inductor and two caps, which is quite unique for a 3 way system. The new design also has all three drivers wired in phase.
I have separate amps for the H-frames and the tops (currently hosting an 8" full ranger) and my main concern is a greater distance from tweeter (ear level) and the center of the 18"s. Is this concern justified?
What is your listening distance?
I have used the top sections with H and U frames as well as sealed enclosures. They sound good with any bottom section that maintains tight control up to around 180 Hz.
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Pretty typical, I think. 9-12 feet with the centers of the H-frames six feet apart and pulled out from the back wall some. I love my full ranger tops for moderate listening levels and they have kept me pretty happy for a few years now but on occasion I like to turn it up and their power handling (95db @1w/1m, 30w rated) reveals stress and distortion as I push their upper limits. I'm hoping this design might flesh out the lower mids and maybe give my system some extra headroom for when things get noisy :)
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Dispersion on the XT19 tweeter is pretty good. At a listening distance of 10 ft you shouldn't have a problem. They can play fairly loud w/o any breakup. Your bottom cabinets will likely become the limiting factor if you try to push them.
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Ha! That would be OK then. A pair of 18" in H-frames at loud volumes feels like they are trying to move furniture and internal organs. I'd be quite happy if they were the weak spot in my system ;)
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So what IS the preferred parts list now? Peerless or MCM? D19 or XT? Big caps or an extra choke? I really, REALLY want to build something new but can't afford to throw away money... especially on passive XO components.
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Sorry. I was referring to the current Hestia V designs. I have not attempted to modify the original design as I no longer own them. The original design is an easy build and provides decent results for the effort. All of the components and values remain the same.
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Thanks! I think I'll give them a whirl.
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Anyone have any videos of the original Hestias (or the newer versions) in operation?
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(https://www.audiocircle.com/image.php?id=187952)
Hey Matevana!
Finally completed my Hestia OB (98%). As you can see from the pic I've doubled up the woofers to get a little more low end and elevation on the tweeter. My previous OB project had an Emenance alpha 15, but l never seemed to get a full sounding low end. Using the 2 low end drivers here produce a much better low end.
As I was finishing up one of my Yung 300 plate amps developed an issue, so l had to put together a low end filter and drive the woofers on the other speaker output on my receiver. I'm using an iron core 4.7 inductor and a 33 uf cap. I just guessed on the filter values and used what l had from other projects. Overall the sound is great, but the low end dominates a bit. I'm surprised at how much more bass I'm getting from the 2 10s as opposed to the alpha 15.
(https://www.audiocircle.com/image.php?id=187456)
Thanks for all you do for the DIY community and your research.
John
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I cant find anyone to answer this thorny question, so will ask it here to the designer and builders of this OB.
"Why when building an OB and all options are open to you, do you select a mono pole tweeter and throw away all the advantages of dipoles
I am not trying to start an argument or even criticise, but would dearly love to know the answer as I am modifying my own OBs and have placed great importance on trying to achieve dipole tweeters. Perhaps I am wrong. :scratch:
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fewer choices?
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fewer choices?
Totally agree with that, but is it really a compromise to go with a mono pole tweeter. I would love someone to defend the decision so I can understand the choice on SQ criteria
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Hey Matevana!
Finally completed my Hestia OB (98%). As you can see from the pic I've doubled up the woofers to get a little more low end and elevation on the tweeter. My previous OB project had an Emenance alpha 15, but l never seemed to get a full sounding low end. Using the 2 low end drivers here produce a much better low end.
Hey John! Nice job and I'm glad you're enjoying your new setup. I'm on a guick lay over in Guangzhou so I only have access to a calculator on my phone, but assuming your two 10" drivers are wired in parallel, the cap and coil values you mentioned should net around 200 Hz, 2nd order. That's in the ballpark and you could always experiment later. Talk more later when I get back!
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I cant find anyone to answer this thorny question, so will ask it here to the designer and builders of this OB.
"Why when building an OB and all options are open to you, do you select a mono pole tweeter and throw away all the advantages of dipoles
I am not trying to start an argument or even criticise, but would dearly love to know the answer as I am modifying my own OBs and have placed great importance on trying to achieve dipole tweeters. Perhaps I am wrong. :scratch:
The original Hestia was a hybrid OB and made use of drivers that I had worked with previously. It was more 'proof of concept' that was easy to build and modify... and light on the wallet.
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The original Hestia was a hybrid OB and made use of drivers that I had worked with previously. It was more 'proof of concept' that was easy to build and modify... and light on the wallet.
Thanks for contributing to the debate. So can I assume that if costs are equal between tweeters then a dipole is better suited to an OB baffle, but if one is prepared to spend more on the monopole it may well outperform the cheaper dipole.
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Thanks for contributing to the debate. So can I assume that if costs are equal between tweeters then a dipole is better suited to an OB baffle, but if one is prepared to spend more on the monopole it may well outperform the cheaper dipole.
Likely depends on who you ask. All of Linkwitz's mainstream designs (Phoenix, Orion, LX-521) used monopole tweeters in either single or back to back configurations. He commented on experimenting with various dipole drivers (both dynamic as well as ribbon, AMT, etc.) and the lack of dynamics associated with some of these.
My most recent experiments make use of a well behaved full range dynamic driver mounted in an open baffle, coupled with a rear mounted, up-firing, monopole tweeter (crossed very high, i.e., 20kHz first order) for ambient sound.
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Thanks. That Linkwitz stuff makes for interesting reading. Out of interest what tweeter are you using that gives worthwhile output above 20KHz?
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FaitalPro HF-102. It’s about 95dB @ 20kHz, 1w/1m. It’s compression but sounds like a quality dome tweeter on steroids.
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FaitalPro HF-102. It’s about 95dB @ 20kHz, 1w/1m. It’s compression but sounds like a quality dome tweeter on steroids.
That's a company I have not come across before. They do a bewildering amount of 1" drivers. How on earth do you chose? In addition I have always assumed that compression drivers need a horn. Am I wrong?
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You probably want to use a short-throw horn or no horn at all, depending on your ceiling height. It's best to keep the dispersion fairly narrow when reflecting off the ceiling for ambient fill. The highest frequencies will radiate into the room the same way a cymbal disperses energy. I have found the rules for ambient tweeter setup to be different from everything else. Try crossing high with a single cap; I am using a 0.15uf Mundorf Supreme with my FaitalPro HF-102. It has a big impact on my front firing full ranger and is quite seamless.
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You probably want to use a short-throw horn or no horn at all, depending on your ceiling height. It's best to keep the dispersion fairly narrow when reflecting off the ceiling for ambient fill. The highest frequencies will radiate into the room the same way a cymbal disperses energy. I have found the rules for ambient tweeter setup to be different from everything else. Try crossing high with a single cap; I am using a 0.15uf Mundorf Supreme with my FaitalPro HF-102. It has a big impact on my front firing full ranger and is quite seamless.
Thanks, I assume without the horn loading the 107dB sensitivity will be very much reduced, which is good as my mid range driver is 95dB. This may avoid the need to put a horrible volume control on the tweeter.
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With a small value cap (0.15uf - 0.22 uf) you likely won't need to worry about attenuating the horn driver to match other drivers. What comes through are mostly high register reflections and other spatial queues. An interesting test is to sit in the listening position and have someone connect and disconnect the driver to better appreciate the effect. It's not insignificant, yet if you listened to the driver on its own, you would likely not be impressed.
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Try crossing high with a single cap; I am using a 0.15uf Mundorf Supreme with my FaitalPro HF-102. It has a big impact on my front firing full ranger and is quite seamless.
Sorry to be a nuisance, but there are lots of caps under the Supreme banner. Which one are you using?
https://www.hificollective.co.uk/components/m_cap.html (https://www.hificollective.co.uk/components/m_cap.html)
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Sorry, I’m actually using a Jantzen Z Silver cap with the HF-102’s. It’s a 0.15 uF value. I preferred this to the Mundorf cap that I had on hand, when coupled with the compression drivers.
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Hi Matevana
I am about to order a pair of these drivers, but remain intrigued as to how you came to discover that a professional compression driver could make a good job as an ambient 'super' tweeter. Up until this point I had never come across this Italian brand for Hi Fi.
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Since I was only interested in reproducing the highest audible reflections, I needed a driver that would play fairly loud in the 15-20kHz range. Most drivers are rated for loudness using a weighted average, so even if you were to find a dome tweeter with an average SPL of 95dB, it might be as much as 10dB lower in the 15-20kHz range. Pro sound drivers however routinely produce higher SPLs across their usable spectrum, so it's just a matter of finding one that plays loud enough approaching 20kHz. While many pro sound drivers may not be considered "hi fi", several non titanium diaphragm drivers come close. I would consider some of the FaitalPro drivers to fall in that category.
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Thanks again M. I will put any updates on my own thread to save high jacking this one completely. Sorry to other readers :)
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No worries. If the information is useful to others, it's a good thing!
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Sorry, I’m actually using a Jantzen Z Silver cap with the HF-102’s. It’s a 0.15 uF value. I preferred this to the Mundorf cap that I had on hand, when coupled with the compression drivers.
Hi Matevana
Just running the capacitor values through the on line calculator - are you sure that's not 1.5uF rather than 0.15 as you recommend. :dunno:
I make it that a 2.2uf capacitor would give a cut off of 9Kz in an 8ohm tweeter, which seems about right.
Thanks Chris
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A first order electrical crossover (1 capacitor) has a very shallow slope. If you go with a 2.2 uF cap it will attenuate only 3dB at 4500Hz, 6dB at 2250Hz, etc. If you plan to use the compression drivers as a super tweeter, you will likely want a cap with a much smaller value, or use a steeper slope (2nd, 3rd or 4th order crossover).
In my setup, (Jordan & Markaudio full range drivers) I've had good luck with a 0.15 uF cap on the FaitalPro driver. My goal was to not draw attention to the compression driver, have it augment the highest octaves only, and not detract from the full range drivers. I got lucky b/c the combined sensitivity of the full range drivers was a close level match with the FaitalPro's output above 15kHz so it didn't require any attenuation (l-pad). In my experience, you should barely hear any additional level gain from the output of a super tweeter when it is properly implemented.
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Thanks again Matevana. My aims are the same as yours and your knowledge is much greater. I will go with that :thumb: :thumb:
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Finding the right value cap for my tweeters is an exercise in trial and error. Alligator clips and listening to a variety of caps takes time but it's worth it.
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Finding the right value cap for my tweeters is an exercise in trial and error. Alligator clips and listening to a variety of caps takes so time but it's worth it.
100%
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Thanks again Matevana. My aims are the same as yours and your knowledge is much greater. I will go with that :thumb: :thumb:
Hey Chris,
One thing you might try per Poultry’s suggestion is to buy a bunch of cheap caps between 0.15 and 1.0 uF and do some testing yourself. Once you have your drivers dialed-in, then go order a more expensive premium cap. Many of the small value non polarized caps are under a buck.
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Thanks guys, my current 'stock' of capacitors starts at 1uF and goes upwards, so its back on e bay for some caps for the experiments. :D
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Hey Chris,
One thing you might try per Poultry’s suggestion is to buy a bunch of cheap caps between 0.15 and 1.0 uF and do some testing yourself. Once you have your drivers dialed-in, then go order a more expensive premium cap. Many of the small value non polarized caps are under a buck.
Continual apologies for my ignorance, but are ceramic caps OK for crossovers. They are cheap and plentiful but I'm not sure I've seen them employed there.
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I've never used them in crossovers since they are usually intended for low power ICs. I'd suggest the cheapest poly caps you can find for testing. Parts Express has the Dayton brand which work well and aren't expensive. You can try 0.15, 0.22, 0.38, 0.47, and 0.68 uF values. You may find you only need 1 each for testing (mono), but up to you. Combining two caps in parallel will increase capacitance (just add the two values together) so the above caps can yield many different values in combination. A set of alligator clips also comes in handy while testing.
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Plan on doing this build.
A couple questions:
The Dayton woofer has an fs of 50.5 fs vs mid 40s mentioned early in this posting. Has something changed? Should I be looking at a different driver?
https://www.parts-express.com/pedocs/specs/295-030-dayton-audio-pa255-8-specifications-46882.pdfP
The specified 1.4 mh inductor is currently not available from Psrts Express. Can I substitute a 1.5 mh inductor with minimal impact?
Thanks in advance for your help. This looks like a great project.
Bill
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Hey Bill,
With a baffle this size, 10 Hz on the woofers low end will make little difference. Aside from listening in the near field, cancellation will set in before you would likely detect a difference. Yes, I would suggest opting for an inductor one size larger (not smaller) if you have to make a crossover swap. 1.5 mH should be fine. Have fun!
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Thanks for the quick reply. I am off to the races and hope to have this done by mid January.
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They are finished!! Very pleased with how they turned out, especially how they sound. Great design... thanks for putting this out there.
(https://www.audiocircle.com/image.php?id=189114)
(https://www.audiocircle.com/image.php?id=189117)
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Badwater, those look great!
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Looks great in the room. Nice job!
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I just re-read this entire thread for the upteenth time over the last several years and one question still pops up in my head...
What if you had doubled your budget for this build?
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I built mine without the woofer with the same baffle width and mid and tweet location and used the Golden Ratio for the height. Using them near field with a Nelson Pass ACA amp kit and they sound wonderful. I too wonder if using more esoteric drivers would increase the pleasure ( or just drain the wallet)? After some thought, I do not think more expensive drivers would be a wise investment with this design. it is very darn good just the way it is. Using an 8" Yamaha NS-SW050 subwoofer and it works very well.
(https://www.audiocircle.com/image.php?id=262064)