AudioCircle
Audio/Video Gear and Systems => Open Baffle Speakers => Topic started by: matevana on 20 Jul 2014, 04:31 pm
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The Hestia-V Dome:
This time around I got the itch to develop two kits at the same time after coming to the realization that the AMT Tweeter in the "V" isn't everyone's cup of tea. So it was back to woodshed to design the Hestia V-Dome, a smaller more conventional Hestia V.
For those looking to recreate the design, Melby Audio will offer both a finished and unfinished version of the baffle/stand which is milled from void free 19mm ply with a maple face. The kit is shipped as a flat-pack and arrives looking like this:
(http://www.audiocircle.com/image.php?id=102516)
At the present time, the mock-ups are shown here, still awaiting final selection and testing of the critical midrange driver:
(http://www.audiocircle.com/image.php?id=102517)
From what I have heard so far, I really like the new Markaudio Alpair 6P (paper) driver. Unlike the original V which is designed to feature the Dayton AMTPro Tweeter, this version will use a dome tweeter and lower midrange to simply compliment the fullrange driver at both ends. The plan is to run the Alpair either fullrange or rolled-off slightly on the low end for greater power handling.
(http://www.audiocircle.com/image.php?id=102518)
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Wow -- this one is interesting too. I'd be very curious to hear your impressions should you try the Alpair 6p in here.
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Wow -- this one is interesting too. I'd be very curious to hear your impressions should you try the Alpair 6p in here.
I only have one Alpair 6p that I got for testing. The North American shipment is apparently on the slow boat from China (literally) and should arrive at Madisound by late August. It's a bit frustrating that the one driver has promise, but I really need to listen to a stereo pair to fully evaluate them in the Hestia V-Dome. In the meanwhile I will probably test a few other drivers, if for no other reason than to kill some time.
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Are the pointed shoulders on the baffle around the woofer critical to performance? I think rounded to follow the contour of the woofer would be better aesthetically. Give the speakers a pleasing, rounded jug shape. But that is just my preference. I find the sharp corners distracting and potentially dangerous.
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The overall baffle shape was done in homage to Siegfried Linkwitz and his LX-521 design. He states that the baffle shape was derived after many acoustic free field measurements. His design evolved from minimal width baffles around each driver which might yield a more uniform radiation pattern.
My designs are primarily focused on the combination of driver selection and passive equalization that allows for single amp use with no additional active circuitry. In my last two design (The Hestia V and Hestia V Dome) I borrowed the overall baffle presentation in hopes of benefiting from some of Mr Linkwitz's design goals and research. I also happen to really like the shape of the more angular LX-521. Programs like the Edge often suggest that round baffles around woofers do not yield great results, particularly in OB, where baffle diffraction is concerned. Perhaps this is why we see so few designs like this. Regarding safety and the protruding shoulders, I have not found this to be an issue, even in tight quarters.
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When the distance from a circular driver's centre to the edges of the surface it's mounted on is similar in all or most directions, a circular baffle representing the extreme case, the deleterious effect of the baffle shape on the frequency response is maximized. Counter-intuitively, when the baffle is rectangular, the distance from the driver centre to the baffle board edges varies as you move around the driver, smearing the edge effect over a range of frequencies with no particular emphasis at any one frequency, especially if the driver is not centre mounted. Some of Linkwitz's baffle board designs go further than a rectangular baffle and spread the effect over a still wider range of frequencies.
Lyngdorf does something similar in their DP1:
http://lyngdorf.com/products/loudspeakers/dp-1
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Thanks Russell, that actually makes perfect sense. In some designs I offset the tweeters in hopes of spreading the defraction properties so they are irregular and somewhat less apparent.
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This weekend I will do some listening tests with the Alpair 6p as well as the Seas MU10RB-SL in the design. The MU10 is the same upper midrange used in the Linkwitz LX-521.
(http://www.audiocircle.com/image.php?id=103343); (http://www.audiocircle.com/image.php?id=103344)
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Thanks for the informative replies. I get it now. Size (and shape) matters. :lol:
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Sadly, I'm not sure that the Alpair 6P is the best choice in OB. The "built-in" baffle step compensation produces a somewhat hollow midrange. I can see where this voicing might work well in a more traditional boxed enclosure, requiring fewer components to counter baffle step. I really wanted to like this driver, considering its build quality and good looks, but I find myself missing the rich mids from my Seas FU10's in the other room (Hestia V). I look forward to trying the newer Seas MU10 on the Hestia V-Dome this weekend. It is very similar to the FU10, but has a slightly lower Qts and a modified rubber surround. It is also 4 ohms nominal.
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Interesting - thanks for the update :thumb:
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Completed build with the Seas MU10's mounted, front and back views. Now for a weekend of testing and tweaking! I'm getting to appreciate crossover design at least as much as driver sourcing, baffle design, and fabrication.
(http://www.audiocircle.com/image.php?id=103588)
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(http://www.audiocircle.com/image.php?id=103830)
Minimalism
Despite their similar appearance, the Hestia V-Dome differs from the Hestia V in several ways. The ultimate goal of the Hestia V project was to exploit the strengths of the Dayton AMTPRO driver, namely its speed and clarity. The Hestia V-Dome, on the other hand, strives to be liked by the full- range enthusiast (despite the appearance of multi-drivers) for its design philosophy and execution. The V-Dome exploits the merits of the Seas MU10 driver and attempts to make up for the few weaknesses it has.
In the typical full-range, single driver system, the appealing sound characteristic comes from the lack of a conventional crossover. In a two-way speaker, for example, the acoustic phase of each driver rotates in opposite directions around the crossover point. While the combined phase may be correct at the crossover point, away from that point, the phase will be constantly changing. The human brain is designed to locate sounds primarily by phase. We are particularly sensitive to phase in the 300-3000 Hz range. If the phase relationship is less than correct, the sound stage often lacks precision and depth. By eliminating the crossover and the attendant phase problems, a single driver speaker sounds much more natural and coherent.
But single driver systems in an open-back alignment have their own challenges. Without the support of a box to cancel the driver’s rear wave, most medium sized drivers will not offer enough bass support in OB. And while many capable full range drivers remain clear and articulate up through the higher octaves, many can also benefit from the reinforcement and wider dispersion that a small dome can offer.
(http://www.audiocircle.com/image.php?id=103831)
The crossover design in the V-Dome should be considered minimalist, allowing the Seas MU10 to play throughout its entire range, with only a single high quality resistor used for level matching. There are no inductors or capacitors which would effectively alter this driver’s phase relationship. The Eminence bass driver and the Vifa ¾” dual ring radiator are only used to support the MU10 at its extremes, in areas where the inherent OB properties might override the benefits of a single driver approach. Even their integration is done with a first order methodology to minimize phase abnormalities. With few components in the chain, the extra detail that is maintained by better quality caps and coils is well worth the expense and the benefits are extremely audible. Lastly, the upper and lower x/o points are positioned well beyond the frequencies that we are most sensitive to.
Driver: Component:
Eminence B102...............9.00 mH 15 AWG Sledge Hammer Inductor (series)
Seas MU10RB-SL.............Mundorf 15 ohm MOX metal oxide film resistor (series)
Vifa XT19.........................Mundorf 1.5 uF EVO Oil capacitor (series)
All drivers are wired in-phase. There is also a 10 ohm shunt resistor placed across the two auxiliary terminals (in parallel) of the Eminence B102. Here too I am using the Mundorf MOX brand. This is a critical part of the woofer integration. Without it there is too much high frequency overlap from the B102. The resistance across the terminals helps the large inductor track better and chokes at least one additional octave of high frequency information. In this alignment the Eminence B102 reinforces the lower octaves of the MU10's range and it sounds like one coherent driver.
(http://www.audiocircle.com/image.php?id=103876)
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I really like what you are doing here, there is an elegance to the shape that's appealing! Having played around with my quick OB set-up, I'd now like to follow your ideas of the V-Dome. As I will be making it (or similar) myself (in UK), is it possible that you could provide a drawing or basic dimensions? I'm attempting to replicate the design on CAD, but it's a lot of guesswork!
Is there any advantage in selecting the Seas MU10RB 4 ohm speaker rather than the 8 ohm FU10RB? Their specs look very similar, you have a larger resistor in the crossover compared to the V; I'm wondering if it is better to have 8 ohm driver that doesn't need restricted? Hope this isn't a silly question!
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Hi Tony,
One of the reasons the Hestia Dome has a larger resistor value is that in it's design the resistor is the only component affecting the midrange driver. The Hestia V for example includes a bandpass circuit. The inductor in that circuit adds it's own resistance which gets compensated by using a resistor with a smaller value.
It's a bit odd, but I think I prefer the overall presentation of the MU10 to the FU10, even when used full range. That being said they are VERY close in character and I'd be hard pressed to tell them apart if I didn't already know which was which. Ironically the FU10 was designed by Seas as a fullranger, while the MU10 provides the midrange coupler function in Linkwitz's LX-521. I believe the surround material is supposed to be more transparent in the MU series, at least where midrange performance is concerned.
I'm on the road for a few days, but will post the critical dimensions of the Hestia Dome when I return.
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Tony,
I have the Autocad files (.DXF/.DXT) for the Hestia Dome baffle and base. If you PM me, I will email them to you. It is the same file used to cut the plywood on the CNC machine.
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Just wondering - what difference is there if an H-frame has or hasn't a top or bottom? I'm asking because I can get 8 1 foot squares from a standard 4' x 2' mdf sheet to make two H-frames. Each with two sides, top and the fourth square to mount the woofer. No bottom.
Is the woofer's mdf square positioned halfway into the frame, or about 1/3 in?
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Hi Tony,
The baffle is positioned halfway between the front and rear of the cube. Theoretically you can omit the bottom, if the cube is placed on a well damped, solid surface. If you omit the top, there will be too much cancellation. Note that omitting either the top or bottom may compromise the integrity and result in additional cabinet resonances, even with 1" MDF. I continue to recommend the pre-fab "paper" cubes since they are surprisingly well damped and easy to assemble.
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How is this development going?
I really like the clean design and passive crossover. Possible to share more info of how to build it?
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They are complete and I like them very much. I am going to be experimenting with an active crossover (bottom section only) over the holiday break. The passive crossover used with the Peerless SLS drivers sounds nice but is limiting the gain to the Adcom GFA-565 amplifier that drives them. I plan use a DBX 223xs crossover which will provide proper gain to the Adcom and offer a 24dB/oct rolloff. That being said I would not want to change the top section at all. In fact, I often run them w/o the Peerless and they sound very nice. I will post my observations over the break.
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Christmas greetings everyone!
(http://www.audiocircle.com/image.php?id=111098)
Here are my efforts so far. Vifa XT19 with 1.5 uF in series; Seas FU10 with 30 uF in series and an L_Pad. Both driven from an Arcam A38 amp.
10" FaitalPro and Seas 8" (in H-frame) U22REX H1659-08 wired together in parallel, driven from a miniDSP and Myryad amp.
I don't know if all this makes acoustical sense? - I am pleased with the sound so far; cellos and the lower piano notes have a good vibrancy and the elephant in Saint-Saens' Carnival of the animals is definitely in the living room!
I'll relax and listen to music as opposed to 'sounds' over Christmas and then try to develop it further...
Any suggestions as to where to go next gratefully received - I still feel I'm groping in the darkness!
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Hey Tony,
Looks very nice! Congrats. :)
I'm intrigued by your description and have a few questions at your leisure. Did you mean that both the Faital and Seas drivers are wired together and driven by the same amp through the MiniDSP? If so, can you go into a little more detail on this. Are they wired in left/right pairs or mono? Do you remember the MiniDSP settings for slope and crossover point? It sounds like in your version both the 8" and 10" drivers are crossed the same, so you essentially have a 3-way instead of a 4-way... or maybe I misunderstood.
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Did you mean that both the Faital and Seas drivers are wired together and driven by the same amp through the MiniDSP?
Yes, I had tried an 8 mH inductor with the Faital, but didn't seem right and I wasn't sure what to do next. Then when I got the Myryad locally at a sensible(ish) price and the MiniDSP from Ebay. I reckoned that the DSP had plenty of adjustments which might deal with all the bass end in one go.So it is, as you say, a three way system.
Do you remember the MiniDSP settings for slope and crossover point?
After Christmas I'll give you details, if you don't maind waiting a few days. I'm still fiddling around with settings, once I get a longer USB extension it will be easier - from a comfy seat, not crouched on the floor behind the speakers!
I'll also save a graph from REW for you to comment on. Am I right to place the mic 6 to 8 ft in front of the speakers (the region where I sit) and point it upwards?
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Sounds good and take your time Tony! Always interested to hear someone else's approach. The great thing about speaker design is there are often many ways to accomplish the end-goal. Happy listening!
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Tony, you are not getting all the potential out of bass drivers if tehy are coupled like that. They definitely should have separate dsp channels. Which model is your minidsp? If something must be passive let it be mid to tweeter xo. Delay settings are also quite important . Typically we need one 2x4 for each speaker or a 4x10HD which handles both L/R. Lots of amplifiers too!
Here is good info about using minidsp for multiway dipoles http://www.hifizine.com/2011/03/refining-a-4-way-open-baffle-speaker-minidsp-2x4/
And you should read this too http://www.hifizine.com/2010/12/prototyping-4-way-open-baffle-speaker-with-the-minidsp-2x4/
A measurement system based on FFT is needed. REW is free and simple http://www.roomeqwizard.com/
Minidsp UMIK-1 is nice http://www.minidsp.com/products/acoustic-measurement/umik-1
DSP is extremely flexible and potent tool for Obs. Look at http://www.linkwitzlab.com/What_is_new_at_linkwitzlab.htm (http://www.linkwitzlab.com/What_is_new_at_linkwitzlab.htm) and NaO NoteII RS http://www.musicanddesign.com/NaO_Note_II_RS.html
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Hi folks
you are not getting all the potential out of bass drivers if tehy are coupled like that
Yes, I'm aware it's not the best method but I'm limited to what resources I have withoit spending a fortune! I'm aiming to boost the bass response as much as I can. Perhaps it would make more sense if both bass woofers were the same? I don't want to widen the baffle too much with 15" drivers. And with only a few inductors and caps to play with the minidsp gives me plenty of flexibility.
I have the miniDSP 2x4 and settings are -
(http://www.audiocircle.com/image.php?id=112053)
(http://www.audiocircle.com/image.php?id=112054)
(http://www.audiocircle.com/image.php?id=112055)
These are the settings - at the moment! - the minidsp input is from my ARCAM a38 pre-out and its output goes into a Myryad amp.
Do different amps create any timing or other difficulties?
So, the 10" FaitalPro and Seas 8" (in H-frame) U22REX H1659-08 wired together in parallel, The Faital seems to be the louder.
Seas FU10RB now has a 270mH inductor in series as well as the 30uF Cap. Yesterday I mounted this driver behind the baffle - 20mm - rather than halfway which seems to have taken the shrillness from it. Because of this I've taken out the L-Pad.
I have replaced the Vifa tweeter with my Fountek Neo CD3.0 (from an IPL TL kit) which I think is better (or is it? Not a great deal of difference). It's mounted behind the baffle (12mm) as I don't want to carve out the hole at this stage. 1.5uF cap and 5R6 both in series.
With the speakers about 3' 6" from the wall behind them, 6' 6" apart and a mic 10' in front I get this graph -
(http://www.audiocircle.com/image.php?id=112058)
What are your comments arising from the graph?
All this probably sounds crazy to you experts! However, I have got a system which, even at this stage, is way better than anything I've had before, and friends have been impressed.
So what next?
Thanks Juhazi for the links - I have looked at - but not 'studied' them! There is a lifetime's reading out there!
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Hey Tony,
Here's a quick experiment you can try. Take the Seas 8" driver out of the loop and conduct the same test. I'm not sure the driver is adding anything in this setting and the amp may have better control over the Faital's VC without it. If that improves the sound, the next step would be to add back the H frame, but this time under the separate control of a plate amp/crossover when you can afford to do so.
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Hi,
I've two graphs here, the black line is with all 4 drivers.
This first one I have taken out only the Seas 8"
(http://www.audiocircle.com/image.php?id=112506)
In this second graph I have taken out only the 10" faitalPro.
(http://www.audiocircle.com/image.php?id=112507)
I've made a change since my last post - The Arcam amp has a button to seperate the pre-amp from the speaker amp part (is there a name for this?), so I've taken the other two outputs from the MiniDSP for the mid and tweeter. Like the bass, I'm feeding the mid and tweeter together with the crossover I gave in an earlier post.
No doubt a 2x8 MiniDSP would be better (with more amplifiers!), I'm trying to make the best use of the resources I have at present.
I haven't yet listened to music without one of these bass units - I'd better do that next and get some idea of what contribution they make on my ears
Anyway, it's a good improvement!
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Kind of what I suspected in this case. The Seas driver is just mimicking the more efficient Failtal Pro driver and if anything contributing to a curve that is less flat, and probably some audible doubling in the lower frequencies. If you relegate the H-Frame to a low-pass of no more than 90-100Hz you will reduce some of that low register smearing and clean up the funk. This will also help to fill-in the lowest register which is somewhat lacking presently.
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Hey Ed (Matevana),
Assembled my drivers for the Hestia V Dome and I'm about to order my flats for the project. I have some large enough scraps of 3/4 Birch ply and want to experiment with my current open baffle driver (for a second system later). Currently I'm using the Tang Band 1808 driver with the Alpha 15 and it sounds great. Interested in the Hestia because I would like a larger sound presentation. And if the Hestia has anything close to the presentation of the Linkwitz project and only require 1-2 amps, I would be very happy.
I would hate to just box up my 1808 drivers. Could it be substituted for the Seas midrange with the Eminance and tweeter? In a previous topic you suggest that I use a conventional L-pad with 2 resistors on the Eminance. That is in addition to the 9.0 inductor, correct?
John
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Hey John,
Remind me what you are proposing for each of the drivers and whether you plan to use one or two amps?
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Ed.
Building the Hestia V Dome. I have the Seas, Lil Buddy and the Vifa tweeter. Also, using the Alpha 15 for the bottom. I have a cap and 4.7 inductor on the Alpha.
As an experimental second system I thought I would reuse the Tang Band 1808 instead of the Seas midrange. At the moment I am using just one amp driving the Tang Band and Alpha. In the future I plan to use plate amps to drive just the Alpha 15s or an upgraded version.
The Tang Band 1808 is about 94db and has a very nice midrange. In its present application I have no filtration on the driver - using it full range.
I also plan to use all of the filter values you recommended for each of the drivers.
John
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You could but I suspect the presentation will be very different. The crossover will take some work as the 1808 is more efficient than the Seas midrange, and will likely produce more overlap than the Seas as well. This will result in a more forward presentation. Still though, it can be done with a little trial and error, or the right modeling tools.
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Hi Matevana,
I've left the bass units in abeyance at present and decided to put in the Jordan Eikona 2. Wow! What a difference! Instead of asking myself "what can I do next to try and make the sound better?" I now am asking "Is there anything I can do to make it better?" I left room for a tweeter, but I'm very doubtful if it is needed - maybe my elderly ears of course! Sometimes speech sounds as if it needs sharpened up, but again my ears? I do have some loss around 4000 hz and up.
About the bass units, supposing I put two the same each side, such as 10" Seas similar to that which Linkwitz has used in a W-frame, connected in series, would that make sense? I'm thinking of a two way system using a MiniDSP and limiting size to 10" for space reasons. Perhaps the SEASL26 R04Y D1004. Fs 24, sens 85.5, Qts 0.27, power rms 250?
At present I have the low pass at 250 LR48/octave, high pass at 50 LR48/octave with a little equalisation top and bottom. What I'm getting sounds pretty good, the SPL does show a falling off at the high end.
I'm waiting for a couple of pairs of ears to listen, ears that have had experience in broadcasting and hi-fi business.
Are you any further on with your project?
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I've heard the Ted Jordan original metal cone driver. It can sound nice. I'm sure the later stuff is even better. Can you remind me what your current configuration is? (drivers). If you are using a full range driver, you should not have significant loss at 4k. Most are pretty prevalent in that range and start to peter out 12-14k.
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10" FaitalPro and Seas 8" (in H-frame) U22REX H1659-08 wired together in parallel, driven from a miniDSP and Myryad amp. Jordan Eikona 2 driven from Arcam A38, using the other 2 channels on the MiniDSP.
(http://www.audiocircle.com/image.php?id=120741)
This was with the crossover at 100; I should have remembered before posting that I've altered the settings since! I'll set up the mic again when I've time.
(Why is there always less time to do anything in retirement?)
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In the process of starting my Hestia build. One question about the bass unit.
Have the Alpha 15 and the Delta 15a. (Will use one or the other)
Would like to build a bass bin enclosure. Is there a golden ratio regarding the size of the enclosure?
John
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In the process of starting my Hestia build. One question about the bass unit.
Have the Alpha 15 and the Delta 15a. (Will use one or the other)
Would like to build a bass bin enclosure. Is there a golden ratio regarding the size of the enclosure?
John
To my knowledge the golden ratio referred to in box construction is designed to tame standing waves within a sealed or ported enclosure. While standing waves can exist in both U and H frames, the effect is minimal by comparison, so other design parameters often take priority. You might want to take a look at Martin King's paper on comparing U and H frames; in it he discusses the effect of both frame width and length. His paper is located here: http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf (http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf)
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They are complete and I like them very much. I am going to be experimenting with an active crossover (bottom section only) over the holiday break. The passive crossover used with the Peerless SLS drivers sounds nice but is limiting the gain to the Adcom GFA-565 amplifier that drives them. I plan use a DBX 223xs crossover which will provide proper gain to the Adcom and offer a 24dB/oct rolloff. That being said I would not want to change the top section at all. In fact, I often run them w/o the Peerless and they sound very nice. I will post my observations over the break.
Hi Ed,
Decided to go with the Peerless 830688 drivers. Are you using a second order passive filter or did you implement the DSP? Found the post above but could not find any other information. Thanks,
John
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Hey John,
I'm using the DBX 223 on the bottom section only. It's a good quality analog electronic x/o. Since I run passive preamps, I experience a level problem with most digital x/o's like the MiniDSP. The DBX unit has more than enough gain to drive my Adcom power amp to the proper level. They are also silent.
The DBX 223 has a fixed 24dB/oct slope which is a bit steep for many OB designs. To get around this, I run the bottom end in mono and parallel the input. The left channel is then set to overshoot the intended crossover frequency while the right channel undercuts it by the same amount. Not perfect but this tends to simulate a more shallow slope (something closer to a 12dB order) and sounds very nice.
The only other changes I have made involve removing the whizzer cone from the Eminence mid-bass unit and replacing it with a standard dust cap and then tweaking the midrange frequency in the x/o.
I am extremely happy w/both the Hestia V (AMTPro) and Hestia V Dome (Vifa x19). I listen to both daily and have no desire to change anything.
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Hi Ed,
I looked at the DBX 223 crossover and it would be a perfect tool if it offered varying slopes - at least 12db per octave. Not able to use it though in my current configuration since I'm using an integrated without pre outs.
You stated that you prefer using a second order filter (on the bass) rather than just an amp with an adjustable cutoff frequency - such as a plate amp. Wondering if this is possible. I originally was going to employ a couple of plate amps to drive the bass but decided to use the second order filters instead.
Since the plate amps (or any amp with a cut off frequency) only limits the frequency, would it be possible to use the plate amp set at a certain frequency - ie: 100hz - and also use a cap at the driver to complete the second order part of the filter?
Can I also assume that you can use a plate amp set at its highest maximum frequency cutoff ie:150hz but still use a second order filter (cap and a coil) on the bass set to 100hz?
With all the products available to speaker building hobbyist it surprising there is not a source for flexible electronic crossovers at a reasonable price.
Thanks for your help and support for us frustrated open bafflest.
John
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Hi John,
Most plate amplifiers that have an adjustable electronic low pass filter, use a 12 dB per octave slope. In many cases this is all you will need. If you can get one with a variable phase control, and not just a phase reversal switch, this is often very helpful. Getting the phase right can be key to a good integration.
You can always attempt to increase the slope by adding passive filters, separate from the line level filtration in the plate amp. I did some experimenting with this in an earlier project, but in many cases this is not needed.
The Yung plate Amps are a good example of variable phase capabilities. I find this helpful in OB woofer integration, since you can correct some phase anomalies that occur as a result of the reflected low frequencies. This often takes a bit of trial and error, especially if you don't have a good measurement system.
Ed
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Hi Ed
Long time no post.
However, I have been listening to my Hestia SLs for several hours every evening for the last couple of years and enjoying them very much.
I've kept the thought of building the Hestia V, probably the dome version, on the back burner for some time now. My question to you is how much of an upgrade would the V be from the SLs? I hope that is not an unfair question. I'm just wondering if it is worth the investment of funds and time.
Thanks.
Peter
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Hey Peter!
Good to hear from you and glad you're still enjoying the SL's. These things are always subjective and I no longer own the SL's, but I do remember the V's being a fairly big step up when I first built them. I currently own one set of V's with the Dayton AMTPRO tweeters and one set of V Domes's with the Vifa Dual Ring Radiator tweeters. Both are good in their own right. You might also find the separate H/Frame U/Frame lower cabs to be an advantage as well. This allows construction of a separate bridge to minimize vibration transference from the bass driver. The Seas 3" mids (used by Linkwitz) are also really articulate and natural. I've relegated the Eminence bass-guitar speaker to bass duty in the lower cabs (where they excel), and use both Usher and Peerless 10" drivers for the lower mid units. The crossovers have since been tweaked as a result of this change.
If you are looking for a project to get into, I highly recommend either as the next generation. If you're ever in FL, I would be glad to demo them for you as well.
Ed
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Ed, thanks for getting back to me so quickly as usual. I need to do some research but want to make sure I have the driver models correctly. Do I have these right?
Tymphany XT19TD00-04 3/4" Dual Radiator Tweeter
Seas Prestige FU10RB H1600-08 4" Full Range ( you mentioned 3" in your post, but I think you mean these, no?)
The 8" Ushers I used in the SLs are no longer available. Parts Express offers both of the following. Are one of these the Ushers you are using for the lower mids?
Usher 8945A 7" Carbon Fiber/Paper Woofer
Usher 8137A 8" Kevlar/Carbon Fiber Woofer (rather unattractive yellow)
Which 10" Peerless are you using? I very much like the Ushers I am using. Do you have a preference between the Ushers and the Peerless?
Eminence Legend B102 10" Bass Guitar Speaker 200W 8 Ohm
Thanks
Peter
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does melby still offer these flat packs?
thanks,
drmike
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The tweets are the XT19's, the mids are FU10's (Seas calls them 4" but their cone surface is actually < 3") and the lower mids are either Usher 1001B's or Peerless SLS-10's. You can also use the Linkwitz version of the mids (Seas MU10RB-SL) with a small component change. I have one system using the FU10's and another using the MU10RB's and they are extremely close sonically. The Eminence drivers are in fact the B102's.
Regarding the B102's, I have one with the whizzer cones removed and replaced with oversized dust caps and another w/the whizzer cones in tact. Even when used as a bass driver in the H-frames, there is a noticeable difference as to how high they will play. I like them both and really cant say which pair integrates better overall. This was more of an experiment than anything else when they were initially used in the top section.
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does melby still offer these flat packs?
thanks,
drmike
I believe he does. Haven't worked with him since the two designs were released. He does good work and is very reasonable.
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Hi Ed
I hope you will notice this post. Its been two years since I last posted here and I am just now putting this project together. Time flies. I have several questions to run by you before I start construction.
I intend to use the following,
XT19TD00-04 4 ohm tweeter
Seas MU10RB-SL-04 4 ohm fullrange
Peerless 830668 10" 8 ohm low midrange
Eminence Legend B102 10" 8 ohm in WayBasic H cabinets
Would you tell me what your final crossover components are for this setup? I think you made some changes over time and may have changed components.
You have used the WayBasic cubes for the H frame enclosures for some time now. How are they holding up? Reviews on Amazon are somewhat mixed with some complaints of the adhesive not lasting and the cubes falling apart. I would imagine a big chunk of MDF in the center would stiffen and make for a stronger structure. Do you still recommend them?
As for the baffles, you designed them on the Hestia SLs tilting backwards some. I believe that was to make the voice coils of the various drivers line up in the vertical plane. You didn't do that on the forte or the V designs as far as I can see. Do I have your reasoning right and did you decide it wasn't critical?
Also, I noticed at post 19 on the New Build:Hestia V thread your explanation of your decision to rear mount the Seas and the Peerless. Flipping the baffles around and front mounting would provide a fairly substantial roundover on the back side and more closely align the voice coils on the Melby c&c baffles if that is significant. I'm not suggesting a change just wondering what your thoughts are.
I hope you are well and still designing.
Peter
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Hey Peter.
Long time! Good to see you're still in the hobby. I no longer have the Hestia V's; I often sell components to help fund the next project.
I tried to address your questions below. Let me know if you'd like to discuss some more.
Q) Would you tell me what your final crossover components are for this setup? I think you made some changes over time and may have changed components.
A) If memory serves, I only played with the attenuation level of the MU10RB midrange driver, going from the original 15 ohm value to 22 ohms instead. I was also level matching to the Eminence B102 which made up the lower driver on the baffle at the time.
Q) You have used the WayBasic cubes for the H frame enclosures for some time now. How are they holding up?
A) I had no issues with them. The baffle was made of ¾” ply and served to help keep the shell intact. I used construction adhesive on the inside sealing the baffle to the cabinet walls in addition to the Way Basic adhesive strip. Also note that when you orient the cube, the top/bottom is different from the sides. It’s important to make sure it rests on its bottom and not one of the sides. This concept only works (compressed cardboard) due to the absence of any real air pressure inside an H frame. The Way Basics cube really just served to delay the back wave, but the baffle itself was the key structural part.
Q) As for the baffles, you designed them on the Hestia SLs tilting backwards some. I believe that was to make the voice coils of the various drivers line up in the vertical plane. You didn't do that on the forte or the V designs as far as I can see. Do I have your reasoning right and did you decide it wasn't critical?
A) Yes correct. Quite frankly, it’s hard enough getting a reasonable outcome from a 3 or 4 way design, that concepts like ‘aligning a driver’s acoustic center’ often get kicked down the road. Your observation seems right; inverting them may better serve the vertical alignment.
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Thank you Ed
Regarding the components, which might not be easy an answer since you no longer have the speakers and given the time since you built them, I'm not quite sure what they should be. You listed the following earlier in the thread.
Eminence B102...............9.00 mH 15 AWG Sledge Hammer Inductor (series)
Seas MU10RB-SL.............Mundorf 15 ohm MOX metal oxide film resistor (series)
Vifa XT19.........................Mundorf 1.5 uF EVO Oil capacitor (series)
I'll be using the Peerless for the lower midrange and the Eminence will be down in the WayBasics.
Would you recommend the components and values as listed above?
You also mentioned the following.
"There is also a 10 ohm shunt resistor placed across the two auxiliary terminals (in parallel) of the Eminence B102. Here too I am using the Mundorf MOX brand. This is a critical part of the woofer integration. Without it there is too much high frequency overlap from the B102. The resistance across the terminals helps the large inductor track better and chokes at least one additional octave of high frequency information. In this alignment the Eminence B102 reinforces the lower octaves of the MU10's range and it sounds like one coherent driver."
Would that 10 ohm shunt resistor be valid on the Peerless?
I will change the value of the resistor on the MU10s from 15 to 22 ohms.
I know that much of the magic happens at the crossover level and in this case modifying drivers outputs, but it is beyond my abilities so I plead ignorance and ask for your help.
Thanks
Peter
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Be glad to help. First a few questions. Why did you decide to move the Eminence to sub duty and make the Peerless the lower mid? Also, can I assume the H frame will be powered by a plate amp with its own adjustable crossover?
The Eminence is at least 5dB louder and it’s TS parameters are quite a bit different. Not a bad thing, but the crossover will require some changes. The Peerless has better extension on the low end; the Eminence better on the top. All of these things are workable however.
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Ed, I apologize for asking you to revisit a design from several years ago. In post #43 above you wrote ' I've relegated the Eminence bass-guitar speaker to bass duty in the lower cabs (where they excel), and use both Usher and Peerless 10" drivers for the lower mid units. The crossovers have since been tweaked as a result of this change.'
That is what made me plan to switch those two drivers and to ask what crossover changes you made. I am not so far along that I can not switch back again if you think the original setup sounds better.
Thanks
Peter
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Thanks Peter. I actually didn't remember that. I had the Usher 10" drivers in the lower mid position for a short time, before someone approached me about buying the V's. The Peerless 10" SLS has very similar parameters to the Usher 10", so let me see if I can find any notes about the component values used. Is it OK to PM you with further info?
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Sure Ed that would be fine. Sorry to put you to the trouble.
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Hi Ed,
I like your project Hestia V & Dome for his simplicity and low cost.
I'm looking for a good substitute of my omnis speakers.
I bought Lxmini plans already, after that I discovered a lot of other project I'm curious about.
I saw best projects are 4 way and eventually not much more expensive than Lxmini.
But...my room is small: 4.5m x 3.75m x 3m.
My speakers position is along the long wall.
Lx521 and Nao are for bigger rooms.
How far should be Hestia from front and side walls and to sweet spot?
How they perform with big orchestras, symphonies and operas (vocals).
Any advice?
In any case, congrats for your valuable design.
Thank you!
carlo
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Hi Calupi,
Sorry for the delayed response but I have been busy with Work. The Hestia V and V-Dome will require similar breathing space as most full size systems; it's really just physics. In a pinch you could try a half meter from the front wall, but 1 M is generally best.
For the past 2 years I have come around to the full range camp (the dark side). While there are definite limitations such as high intermodulation distortion and limits on maximum volume, there is something about the lack of phase abnormalities that MOST crossovers seem to suffer from. A good 3 or 4 way design, such as the two examples you mentioned, can be very difficult to achieve. My current designs are centered around a well made full range driver, a reasonably sized baffle elevated to ear level, and a well integrated sealed or aperiodically damped woofer. I have been very happy with these designs for longer than I have with any multi-way OB system. I never thought I'd find myself agreeing with FullRangeMan, but as I get older he seems to be getting smarter! 8)