AudioCircle
Audio/Video Gear and Systems => Open Baffle Speakers => Topic started by: -Richard- on 11 Nov 2007, 12:05 am
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Scorpion was kind enough to suggest the Eminence Alpha-15A as a good candidate for a subwoofer to integrate with the B200's in a 2-way OB... the results are fabulous but the path to this success was not straight.
Perhaps 2 years ago I purchased a 15" Hawthorne SI driver and had Jim McCarthy build me a baffle for them with good structural integrity: 23" wide by 36" high. It has a base and top and 3" "wings" that begin "inside" the baffle and meet the sides and attach top and bottom (they cannot be seen from the front). I no longer have the SI's so I had Jim turn the baffle upside down so that the 15" cut-out (hole) was now on the bottom. The B200's are centered over the 15" Alpha-15A's.
I am currently driving the B200's with the Korneff 45 SET (2.5 watt) tube amp and Peppard Magic 5 tube preamp. The Alpha's are driven by a 6 watt integrated Single Ended Pentode tube amp with tone controls. I am using a simple inductor on the Alpha's to cut them off above 270Hz with a -6db per octave fade.
The B200's never sounded this good... never... I think it is because of the greater rigidity of this baffle. The Alpha's driven by the SEP amp sounded a bit soft with an indistinct "tonal" presence. Still... I was amazed at the "potential" this combination suggested.
I remembered reading an article on 6 moon's written by Jeff Day about his positive experiences with a DIY speaker cable project using an outdoor electrical cord... he raved about its tone rising to ever juicier adjectives to explain how much in love with them he was. I decided to try it myself and picked one up at my not-so-local Walmart.
I cut and stripped the electrical cord and inserted the pair of the now speaker cables into the B200's. The sound did not thrill me. It was so articulate on top that it was like finger nails on a school black-board. It did not take me long to identify the problem as my cheapy CD player... just not enough resolution up there to allow these incredibly articulate cables to bring out all the resolution the B200's are capable of... the sound? the B200's sounded like Lowthers or the growing crop of French field-coil drivers... super super articulate, fast... but as Deborah pointed out almost immediately... the incredible spatial depth and ambient "presence" that the B200 serve-up with such pleasure using cheapy Lowes "speaker cable" wire was all but gone.
Then it hit me that these "cables" could tighten up the Alpha-15A's driven by the SEP and so in they went using the 4.70 copper coil inductor. I went back to using the Lowes cheapy 16 gauge copper wire for the B200's.
That did it... the Alpha's now sound amazingly articulate on the bottom end... the lower frequency tone is clean and musical. With this combination the Alpha-15's... which have the same sensitivity as the B200's... 96-97db's is a perfect match.
The sound I am getting now is fabulous... rich tonally, deep resonate spatial "presence", incredible immediacy, instrumental color and texture that rivals the real-thing and something more. There is now a sense of "totality"... both Deb and I feel that something "whole" and "complete" musically is taking place with every recording... something deeply satisfying... and the all-over effect is very relaxing... for the first time we are experiencing a great calm... a calm has descended over the music that renders it profoundly easy to listen to... and that in spite of the tremendous dynamics released within the music.
For us our search has ended. I have never experienced this level of musical "perfection" before. The thrill is there... with every kind of music. And it is very nice to be able to dial-in just the right amount of bass needed for each piece and for each occasion... late night listening demands discretion... but this OB system sounds just as convincing when played modestly.
The cost of the 2> B200's and Alpha-15A's was $380... I worked out the cost of the baffles with Jim by trading skills. The "cables" combined is less then $20. Those shockingly cheap prices have allowed me to splurge on amps and preamps.
I notice that there is a trend among designers to use 2> 15" woofers with their 8" wide-range drivers. I cannot imagine that would be at all necessary in the intimate setting of most homes. The one Alpha-15A's per baffle is very convincing.
I have gone for most of the over 2 years I have owned and worked with the B200's without a bass driver... trying here and there different kinds of subwoofer combinations. This works perfectly.
I tried the inductor/resistor on the B200's to tame the rise and help to flatten the midbass response... I found it killed that ripe sense of "presence" and space that I love so much and that helps deliver the musical experience to a startling level of realism.
I am just sharing my latest experiences with my OB's. Thanks Scorpion for your excellent suggestion of using the Alpha-15A's... at $60 each it is a very-easy-to-live-with cost solution to "finish" the integration of the bass with the B200's.
If anyone is suffering from budget issues like we are... here is a solution that will truly amaze you... assuming of course that your amplifiers are sympathetic.
What a fabulous resource this OB forum is. Thank you all for your continued help and generous sharing. Thanks to all of you, my home musical experiences are where I never dreamed it could go.
Warmest Regards ~ Richard
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Richard....
Its nice to see your journey has come to an end.....
and you and Deb can enjoy the music !!! Happy listening.... :thumb:
Chris
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Thanks Chris ~
The amount of speaker choices presented by the commercial audio world is staggering... and there are several speaker paradigms... horns, electrostatics, planars, boxed speakers galore, ribbons, open baffles... and within each paradigm there are numerous variations in speaker design... not to mention variations in materials used to build the drivers themselves... each design strategy calls for our attention and promises musical riches.
I have learned how to "listen" by going the Open Baffle DIY path... and using the Viston B200's as the "constant" in my design explorations with their 96db sensitivity opened the door to low power amps... I was finally able to enter the esoteric world of the Single Ended Triode tube amp... which was a parallel journey for me unfolding at the same time as I explored design considerations for my OB's.
I have learned to look behind the hype of the commercial audio world with its emphasis on expensive audio toys and for the most part underperforming recommendations. They have tried to make audio an elitist "hobby" by charging a great deal of money for the underwhelming products they offer and the use of "snazzy" industrial designs to lure in the rich and those attracted to the hobbies of the rich... by using a quasi-scientific jargon to purposefully sound inscrutable... and by creating a "salon" atmosphere of snobbish rude sales people in the audio stores. It worked... for awhile... until a few really visionary people started audio forums like Audio Circle where we could create a community of like-interested people who are willing to help each other find out what things work or do not work and how they work... and to furnish each other with other important information and feedback.
I have learned a great deal in the 3 years I have been involved in AC.
Now I can concentrate on finding music I want to add to my collection and look into the world of large screen front projectors to view the endless parade of films Deb and I watch (we do not watch TV) thanks to netflicks. At least I can start to save money for one.
Warm Regards ~ Richard
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Thats right Richard....the main purpose to own audio equipment....its all about the music !!! :thumb:
And there's much to hear....enjoy. :dance:
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Sounds great, Richard !
We shall be grateful to MJK putting forward the Alpha 15, his simulation models give very accurate predictions of real life performance ! :D
/Erling
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Richard,
Thanks for sharing your experiences. I am running basically the same arrangement, only with the Hawthorne SI woofer instead of the Alpha 15. I think it's a great combination too!
First, what are the dimensions of your baffle?
Second, you mentioned you used the SI. Are you able to compare the bass response from the SI to the Alpha 15? And, why did you decide not to continue down the Hawthorne path?
Also, have you considered using your 45 amp to drive the full speaker system? You may be pushing the limits of 2.5W, but I think it's definitely worth trying. Bi-amping opens up a LOT of options, but in my experience you always lose something.
I assume that the passive 200hz HP is part of why you're bi-amping, which does make sense. But, it seems to me that the B200 is such a robust driver that it shouldn't have a problem seeing the deep bass. I could see that a HP would be unavoidable with a little Fostex, but the Visaton is just a tough driver. Instead, I think the acoustic rolloff of the B200 (on an appropriately small baffle) seems to match well with the first order coil on the Alpha. Unfortunately I don't yet understand the math to calculate the ideal dimensions.
All the best,
Mike
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Nice, Richard! Intrepid adventurers always find the juciest goods.
Total side note - I just sold my Definition Pros and have my TNT Big Fun Boxes newly stuffed with Omega's first generation 8" hemp drivers sitting in the main system. Result? More similar than different. In fact, it's hard to believe how killer they are.
There's a LOT of magic in those 8" paper drivers.
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Hi Michael V ~
First, what are the dimensions of your baffle?
23" wide by 36" high, 3/4" maple plywood, the rim of the B200's rest on a mortised edge so that they are flush with the front of the baffle, the Alpha-15A's are screwed to a rim of mdf board that is itself screwed to the back of the baffle so that a front wave guide is created from the set-back of the Alpha-15A.
Second, you mentioned you used the SI. Are you able to compare the bass response from the SI to the Alpha 15? And, why did you decide not to continue down the Hawthorne path?
I was one of the first to purchase an SI coaxial driver... which we know is essentially a modified 15" Eminence woofer mid-range with a tweeter. The cross-overs were not well implemented for these first iterations which compromised the potential of the SI's to sound their best. Darrel has since revised the cross-over and he feels it is a very different sound then what I heard. Also, and perhaps most important in my "take" of the SI at that time, was the simple fact that I was used to the phenomenal speed of the B200's. The SI's did not seem to have that level of transparency, but that could have been the cross-over issue working against the SI's potential. Darrel now has an entirely new coaxial driver that apparently is state-of-the-art... but it is not cheap... the price is close to field-coil territory.
Also, have you considered using your 45 amp to drive the full speaker system? You may be pushing the limits of 2.5W, but I think it's definitely worth trying. Bi-amping opens up a LOT of options, but in my experience you always lose something.
The combination of Peppard's Magic 5 preamplifier which has a high gain option and the Korneff 45 SET amplifier easily drives the B200's and Alpha-15A's hooked-up in parallel... they both have a high 97db sensitivity... I tried that before I inserted a separate amp for the Alpha's.
I assume that the passive 200hz HP is part of why you're bi-amping, which does make sense.
Not just that... the integrated Single Ended Pentode amp I am using allows me to dial-in the amount of gain for the Alpha's and it has bass tone controls which gives me yet another level of control. We are talking about subtle effects here but it is uncanny how much it affects the "perception" of the all-over quality of sound.
But, it seems to me that the B200 is such a robust driver that it shouldn't have a problem seeing the deep bass.
I am not entirely certain I understand what you are referring to here.
I could see that a HP would be unavoidable with a little Fostex, but the Visaton is just a tough driver. Instead, I think the acoustic rolloff of the B200 (on an appropriately small baffle) seems to match well with the first order coil on the Alpha. Unfortunately I don't yet understand the math to calculate the ideal dimensions.
Are you suggesting that no passive EQ (inductor) is necessary for the Alpha's? Of course that is entirely dependent on the sound one is trying to achieve... for example my cross-over point of 275Hz is higher than most (DIY) designers would find acceptable... it probably creates a sort of fattening of the frequency gamut between perhaps 180Hz and 275Hz which sounds quite nice to me... the British like to introduce that hump into many of their speaker designs because it favors the voice.
If I did not capture the gist of what you are pointing to, please help me to understand exactly what you mean.
Hi Scorpion ~ Thanks for noting that it was MJK who did the "homework" on the Alpha... thanks MJK for your generousity in sharing your vital experience with us.
Hi Lonewolfny ~ You are very kind to offer your congratulations and support... it is always such a pleasure to read your posts and know you are there.
Hi Miklorsmith ~ Please let me congratulate you!!!!!! I have looked at the TNT Big Fun Boxes many times and wondered how they might fit into my life! The buzz about them is rather legendary... so nice that you actually have a pair to live with. You seem to have a knack for acquiring some marvelous audio legends. I am looking forward to your in-depth experiences with Vinnie's new Signature 70.2 monoblocks... I am still saving money for my upgrade... lucky you!!!
Warmest Regards ~ Richard
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Legend might be going a bit far, but thanks. :D I will say they are most un-boxy sounding. I built mine with a slanted front baffle which was a pain to build but works great to utilize floor reinforcement in the bass and still "aim" the driver at the listener.
They are ugly critters but solid as a tank. I stuffed the box around the driver to further minimize back wave energy. I have speaker wires soldered directly to the driver, so it's amp-direct - no interceding anything.
(http://www.audiocircle.com/image.php?id=4973)
Let's say I have the utmost respect for real cabinet guys.
This photo shows with the Fostex 206E which was recently replaced by the Omega driver. I picked mine up used. I asked Louis a while back if I could buy some from him, but he said the drivers were OEM only. I don't know if this has changed, I hope so because they are tailor made for this easy BR box.
Anybody interested in the single driver idea wanting to try it out, I wholly recommend this as a starting point. In fact, that's exactly what I did with these very boxes. These speakers changed everything for me. OB is cool, but not everyone has the space or room allowance to do it. A sheet of mdf or plywood, a little sweat equity and a pair of drivers and that's it - they punch WAY above their price class.
Sorry for the detour, Richard. :oops:
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tnt big fun box
45 litre Box whats the dimensions on that box i hit a wall trying to figure box sizes volumes
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Hi Miklorsmith ~
Please feel free to share whatever news, information and insights you have about anything audio.
Your new TNT Big Fun Box speakers look awesome!!!!!!
Being able to ensconce those formidable speakers in your listening room, I am not entirely sure what you mean by not having enough room for OB's... my OB's even with the addition of the Alpha's are quite modest at being 23" wide by 36" high and the "back" area is only 1ft. or so.
Of course if you are working with the single driver paradigm... pursuing a "purist" approach... and I mean that in the best sense possible... as an entirely worthwhile and high level of aesthetics... then I would more than agree with you... I used the B200's alone for most of the time I worked with them and I really liked the idea of one driver doing everything.
Did you ever try the Voight Pipe design? Dan Mason thought very highly of it and suggested I try it... I just have not gotten around to it... also a cheap DIY solution and small footprint... he felt the sound was beguiling.
Warmest Regards ~ Richard
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I started a different thread to discuss the BFBs. They're just stained mdf - they look much better in the photo than they do in person. The banana paper color of the 206 is a nice compliment to the brown, they look much uglier with the Omega driver.
I built these boxes about 4 years ago, which led to my discovery of Zu. One of the things that's good about the port loading is it might be able to balance out the tonality so one driver could be enough to fill in the bass.
Wow, I thought you needed more back wave space to do OB. Coolness.
I haven't heard the Voigt Pipes. The best known example would be the C&C Abby, correct?
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I currently have a similar setup.
A B200 on top and a 15" warrior on the bottom. It is an 18" wide baffle.
I have an ancient MTX electronic car crossover hooked to a 12V battery that I am using as a crossover.
It has potentiometers for crossover frequency and volume. I am not sure what the cross-over slopes are or how accurate
the frequency labeling is on the potentiometers.
In my experimenting I have set the high pass cross-over on the B200 at 60Hz and the low-pass cross-over on the 15" at 150Hz.
As odd as these frequencies seem, I believe they are the perfect combination.
If I increase the frequency of the high-pass cross-over there is a noticeable fall-off in mid-bass response. This surprises me as I was expecting significant response drop due to the narrow baffle. That is I didn't expect such a low setting to have any effect over a setting around 120Hz, but it does. If I decrease the low-pass cross-over, I also notice a fall-off in mid bass response. If I increase the low-pass filter I notice a muddying in the mid-bass region due to the two drivers having too much overlap. If I try to increase the frequency of both the high-pass and low-pass, I still seem to lose something in the mid-bass. It just seems like that B200 is best if run as low as possible. I could really take the high-pass off of it all together, but it seems pointless to try and drive it lower. The B200 seems much faster than the Warrior 15". That is in mid-bass cross-over region where they start to overlap, the B200 is more articulate. I want to get a Behringer DCX 2496 so that I can more accurately play with these settings and get measurements with a microphone.
I really like the bass from the Warrior 15". The Alphas might be even better, but there is just something about the open baffle bass that seems right.
However, I would like more impact. I am not sure how to get more impact. Another pair of 15", a bigger amp, a better amp, a smaller room, deeper bass?
I think for my music, heavy metal, that deeper bass is not the issue. And since a smaller room isn't too practical I think maybe more drivers is what I need.
The amp driving the 15s is a 110Watt JVC RX-D201 digital/hybrid.
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Hi Miklorsmith ~
Sorry for the confusion... my fault... I meant that the actual depth of the baffle was only 1 foot or so from the front of the baffle to the back... my OB's are about 22" from the inside edge to the back wall and 29" from the outside edge to the back wall on a toe-in configuration. I found that bringing them further into the room did nothing for the sound... in terms of where my interests lie. And it keeps our living space tidy.
Hi JeffB ~
I currently have a similar setup.
Nice!!!!!
In my experimenting I have set the high pass cross-over on the B200 at 60Hz and the low-pass cross-over on the 15" at 150Hz.
That seems like a nice configuration... and confirmed directly by your experimentation and careful listening.
As odd as these frequencies seem, I believe they are the perfect combination.
One should factor-in the amplification in this regard... I am certain the characteristics of ones amp could easily influence the "perception" of how your drivers interact with each other and that might be at play here.
I want to get a Behringer DCX 2496 so that I can more accurately play with these settings and get measurements with a microphone.
Some users claim the Behringer does not affect the integrity of the signal as it passes through it... others point out that you are passing the signal through several *cheap op-amps (*price points in the building and marketing niche). What I found in experimenting with EQ devices is that there is a price to pay for sound shaping... loss of sensitivity of the signal being just one of them... and it is possible to "clip" the signal if too much frequency changes are applied. But since almost everyone universally praises there affect on the signal why not try it? However, I am always disappointed by these kinds of EQ shaping devices... they tend to skim-off some ambient "spatial" sound that I find so important in my sense of the "real".
I really like the bass from the Warrior 15". The Alphas might be even better, but there is just something about the open baffle bass that seems right. However, I would like more impact.
I take Deborah's sense of what is musical very seriously... we are partners in audio selections and listening to music. Deb hates "impact" bass and feels it is unmusical. I agree with her. This is just personal taste mind you. Most of the music we listen too is served quite well with the low 40Hz Alpha's... lower than that and our home resonates... and worse... the neighbors can hear it as well. Most of the time a "suggestion" of bass is enough to carry the intention of the music to a convincing level of enjoyment... I am listening for the "total" musical sense... and so I am not particularly interested in the frequency "extremes". There is something that my "brain" needs to hear in order to be convinced that I am listening to a musical performance that seems live... that is... alive!!!! and that is a palpable immediacy and fullness of presentation both harmonically and texturally... a sense that everything is there that was meant to be there. Of course one can always find something to tweak... to get "more" out of ones set-up... if you have the time and energy why not?
But I am satisfied that something in the musical presentation seems full... rich... alive... that sense of complexity is there when the composer wanted you to hear it... and also that sense of ease that makes listening to music such a delight.
Warm Regards ~ Richard
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I have been at many heavy metal concerts where the kick-drum slams you in the chest with every kick. It doesn't sound boomy or exaggerated either.
It just hits you in the most powerful way. Perhaps it is just the shear volume at the shows. I don't exactly desire this at home. I don't want to listen that loud, I don't want to annoy the neighbors. However, I have never felt even the faintest touch from a woofer or subwoofer in a home-audio setting no matter how loud. Sure a subwoofer has a certain kind of impact when it is loud, but is a very different thing. I feel the typical home audio bass impact and the live concert bass impact are so many miles apart, that I can't help but feel something is missing from home audio equipment in this regard. I have felt some amount of impact from two 10's in a car. There is something about the extremely small volume of air in a car that allows this to happen. To some extent it also happens at night clubs. 4 15s in a ported cabinets over a small dance floor at really high volume can make this happen. I have a hypothesis right now that more bass drivers are needed or a smaller room is needed to increase this impact. I only mention it because of the early comment about other people using 2 15s per speaker. I am tempted to try it, but have no idea if it will actually change the impact. I can easily see how this sound is not for everyone.
I really kind of think it is a heavy metal thing. The bigger the sound the better. I once saw the Scorpions at Universal in LA. Mathias Jabs at the end of his solo gets some kind of feedback distortion going between his guitar and amps. It is essentially pure noise. It would have been as irritating as possible except for one thing. That distortion in that room coupled the air like nothing I have ever felt before. The whole ampitheatre shook. There was just something about the way the bass reverberated, it was electric, it was awesome. Something that I am certain will never be recreated in a living room. I think they just have a whole bunch of 15s in ported cabs. Maybe 18s.
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Hi JeffB ~
OK... I see what you mean... you want to know if it is possible to reproduce that visceral level of bass impact in the home that could in some way replicate what you hear at live concerts.
I once read an article by Sam Tellig in Stereophile, where he wondered out-loud whether it was appropriate to play large symphonic works in a home stereo system... yes, I know... that would limit our listening experiences to small ensemble musical offerings... or at least, small orchestral works... like the Baroque "orchestra" as opposed to the nineteenth century full orchestra, with its huge segments of similar instruments that can create a huge sound that in the concert hall has the potential to wash over us with a profound immersion of sound.
I think that question might apply to your situation as well... it might not be entirely appropriate to try and reproduce a level of visceral sound that works so effectively in the live concert, at home... simply because that level of sound requires one's system to shift from being able to play a nuanced, intimate musical presentation to one of sheer musical muscle.
For me it is the intimacy of music that captures my emotional inner life and opens me up to the inner vibrations that inform me that I am really alive.
However, your exploration into whether or not it is possible to at least achieve some level of replication of that visceral bass sound you experienced, just might lead you to discover a more potent application of OB bass drivers that everyone could benefit from... so I say why not go deeper into this and see what you discover!!!!!
Thanks for sharing, JeffB. Please keep us informed of your discoveries.
Warm Regards ~ Richard
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Richard,
Thanks for sharing the details of your baffle. Great minds think alike....my LP crossover on the bass is 250hz, and my current baffles are of similar size (20x36).
To clarify my last post - I was not suggesting omitting the LP on the Alpha; rather, omitting the HP on the B200. I see from one of your recent posts that you have a 60hz HP filter, which is probably below what the baffle step roll-off is doing. So, have you tried running the Visatons fullrange (without any filters)?
Hope this makes more sense.
Regards
Mike
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Actually it was me with the 60Hz high-pass.
I too thought this would be well below my 18" baffles roll-off, but increasing the cutoff point is actually audible as a midbass dropout.
So there is information down lower. It might be significantly rolled off, but I find I like it.
I have actually connected without the high-pass at all. I am not sure if there is a noticeable difference between a 60Hz high pass and no filter.
Unfortunately for me my loaner preamp is now gone and I need the volume pot on my cross-over for the B200 so I have to run it through the high-pass filter at the moment. The previous configuration where I could skip the filter all together was a different enough setup for me to be unsure of the exact result.
I think there are benefits to limiting the excursion of the B200 and benefits in not taxing my 6 watt clari-t. Whether these outway a filter in the signal path I don't know.
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Thanks Jeff. I will try a cap on my B200 at some point, though I admit I'm skeptical!
Are those Warrior 15's still available? I thought I read they were sold out...
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Here is the link to the Warrior 15. They are $45 each right now.
http://www.shredmuzic.com/product_p/813-021.htm
This link has many other woofer selections.
http://www.shredmuzic.com/category_s/47.htm
I got mine for about $20 last year as they came out of a damaged cabinet.
At that price I couldn't pass up running the experiment.
I always wonder if perhaps the Eminence Alpha 15s sound better.
For the moment though I am happy.
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Some of the specs of the 15" WARRIOR-15 are very interesting... they go lower than the Alpha's by quite a bit... the Alpha's only go to 46db with a Fs of 41. The Warrior's start at 35Hz. And they are cheaper. $45 compared to $60 for the Alpha's. I am actually tempted to buy a pair and see if I hear a difference given there lower range in the bass... they are s-o c-h-e-a-p! And 100db sensitivity!!!!!! Rather nice.
RMS Power Handling: 250 watts
TS Parameters
FS 36 hz
VAS 8.29
SD 143.13
Qts 0.826
Qes 0.888
Qms 11.83
BL 12.76
Re 6.40
Nominal Ohms 8
Le 468.73 uH
Mms 98.98
X max 0.25"
X mech 0.5"
Peak Power Handling: 500 watts
Ohms: 8
Frequency Response: 35 to 4600hz
Sensitivity: 100 dB
Magnet: 50 oz.
Basket: Stamp
Voice Coil: 2.5" kapton
Cone: Paper
Surround: Accordion
Binding Posts: Clip Type
Pole Piece: .
Overall Diameter: 15 1/16"
Overall Depth: 5 5/8"
Mounting Diameter: 13 13/16"
Mounting Depth: 5 1/4"
Thanks JeffB for the suggestion and for sharing your current explorations with us.
Warm Regards ~ Richard
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But these woofers do have a lower qts, so the LF output will be less. You will need a larger baffle, or have to equalize them more to get the same output
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Victor: But these woofers do have a lower qts, so the LF output will be less. You will need a larger baffle, or have to equalize them more to get the same output.
Thanks, Victor... very important insight there. In that case I will stay with my Alpha's and make
my life a great deal easier for it. Here are other important insights from Scorpion and MJK.
Scorpion: The Alphas are specified down to 41 Hz now for fs, for music that will certainly be okay. The dipole drop is compensated quite a bit by a raised bass caused by the high Qts value.
MJK:For a driver with a lower Qts the roll off will start well above fs so a stated efficiency is an over estimate for low frequencies.
Warm Regards ~ Richard
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Yeah I could see this driver being part of a great system. I would worry about EQ'ing them for more extension, because their Xmax seems smallish.
Now a pair of them...
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Richard,
Do you have a link for the 4.70 copper coil inductor?
I'm not good at finding these things on the web.
Tnxs,
Jeff
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Jeff,
I'm obviously not Richard but here's the coil I'm using:
http://www.parts-express.com/pe/showdetl.cfm?vReviewRateForm=1&vReviewSource=E&orefer=reviewEmail&vReviewRand=440034440219&Partnumber=266-568 (http://www.parts-express.com/pe/showdetl.cfm?vReviewRateForm=1&vReviewSource=E&orefer=reviewEmail&vReviewRand=440034440219&Partnumber=266-568)
One drawback to the single coil crossover on the bass driver is you need a lot of millhenries, which means, especially with lower-quality coils, the DCR is much higher. I'd be curious if anybody has directly compared different units.
Regards
Mike
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Thanks Mike,
I noticed I have a pair of 12 mH inductors - probably from a subwoofer project.
Do you know what the cut off would be for 12's?
Jeff
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Hi JKelly ~
Looks like you found the inductor you need... great!!!!
I work with PartsExpress... if you ask for a technical adviser when you call and tell him what you have and what you are using it for they can "calculate" the information you need... I always found them extremely helpful.
http://www.partsexpress.com/index.cfm?raid=1&rak=parts_express
you could start here for inductors:
http://www.partsexpress.com/webpage.cfm?&WebPage_ID=3&Start=1&Filter=copper%2Binductors&searchorderby=1&sm=1&so=1&search_type=main&desc=ASC
then click on the upper right hand "page 1 of 8": 1,2,3 and so on to see all the inductor values with prices and pictures. If that link does not work look at the upper right hand area of the home page and see a thin rectangular box that says "Keyword or Part #"... type in "copper inductors" and then click on the red "go" oval to the right of it.
As far as copper coil inductors are concerned... there are 2 "schools" in audio... one school says that only "boutique" parts... parts that have superior spec's... can bring you close to the superior sound that is the actual potential inherent for each specific audio function... the other school shrugs its shoulders and says that as long as the parts meet the principal "value" that the audio function needs to perform efficiently it will take you were you want to go.
Most of the time I start at the "basic" parts concept and see how that sounds... although admittedly in my Peppard preamp I spent $400 more than I intended on "upgrades" in parts... on the advice of friends.
Warm Regards ~ Richard
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Thanks Mike,
I noticed I have a pair of 12 mH inductors - probably from a subwoofer project.
Do you know what the cut off would be for 12's?
Jeff
According to the PE chart: at 8 ohms the roll off would start a little above 100hz and at 4 ohms a little above 50hz.
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Thanks - that seems worth a try.
OK is the coil in series with one leg (positive)?
Jeff
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Jeff,
I'm obviously not Richard but here's the coil I'm using:
http://www.parts-express.com/pe/showdetl.cfm?vReviewRateForm=1&vReviewSource=E&orefer=reviewEmail&vReviewRand=440034440219&Partnumber=266-568 (http://www.parts-express.com/pe/showdetl.cfm?vReviewRateForm=1&vReviewSource=E&orefer=reviewEmail&vReviewRand=440034440219&Partnumber=266-568)
One drawback to the single coil crossover on the bass driver is you need a lot of millhenries, which means, especially with lower-quality coils, the DCR is much higher. I'd be curious if anybody has directly compared different units.
Regards
Mike
Mike,
Wouldn't the elevated DCR of the inductors also raise the Q of the woofers, giving somewhat increased bass performance?
I believe that this is quite often employed by designers to:
1. keep costs down
2. increase bass performance
As always, I may be mistaken.
Best Regards,
TerryO
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Thanks - that seems worth a try.
OK is the coil in series with one leg (positive)?
Jeff
Yes
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OK making some progress.
I will most likely make new panels but wanted to see what the Alpha 15's can do.
Tomorrow I'll wire them up.
(http://mysite.verizon.net/jkelly/ac/alpha.jpg)
Jeff
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Hi Jeff ~
Very nice!!!!! I really like what appears to be a dark bluish-gray "finish"... goes well with the blackness of the drivers. You may find that you do not need quite so much height in the actual baffle from the top of the B200's to the top of the baffle. My B200's are only 4 inches away from the top... I would love to post images of my new baffles but I must confess I do not know how to mount images into a post.
Let us know how it all sounds once you have everything hooked up. Allow for at least 200 hours of burn-in for both drivers... especially the B200's before they begin to relax and open-up.
What CD/dac/universal player and amplification are you using?
Warm Regards ~ Richard
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Just a quick update on my B200 and Alpha's project.
I have been on a bit of a journey this week.
First it took a bit of time to deal with taking the filter off the B200's.
I found it hard to lose that nice warm sound and hear the B200's wide open and hot.
Is that what they sounded like when I first got them?
Also I was playing the Alphas too loud like a kid with a new subwoofer.
The result was that all the magic was gone.
So after going through all my interconnects, speaker cables, power cords, amps
and toe in. I settled in on my Jolida 102b amp driving both the B200's open and the Alphas
with the 12MH coil (for now). The bass is there when it needs it but not overstating
it's welcome. I've gotten the warmth back and restored the detail that was missing
due to the filters on the B200's.
So I do have the 4.7 coils on order to get more of the Alpha into the mix, hopefully
I will have them for the weekend.
Right now, feeling much better and like the fuller sound.
Jeff
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I settled in on my Jolida 102b amp driving both the B200's open and the Alphas
with the 12MH coil (for now). ......
So I do have the 4.7 coils on order to get more of the Alpha into the mix, hopefully
I will have them for the weekend.
Right now, feeling much better and like the fuller sound.
Jeff
A good trick I read somewhere is to use a multitaps power transformer(cheap), that will give you various values of inductance, once you determine the value, then get a high quality type.
this is useful, as you would not be keeping expensive inductors in boxes which you will never use.
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Hi JKelly ~
Your target inductor value is what I am currently working with... 4.70 inductor translates to a 275 cycles cross-over with a minus 6db per octave fade above that. The Alpha's in the same baffle with the B200's sounds seamless to me. I am also using the same amp/preamp for both speakers right now hooking them up in parallel.
I am most interested to read what you will hear when your new inductors arrive.
What CD player/dac/hard drive (whatever) are you currently using with your OB's? Keep in touch.
Warm Regards ~ Richard
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A good trick I read somewhere is to use a multitaps power transformer(cheap), that will give you various values of inductance, once you determine the value, then get a high quality type.
this is useful, as you would not be keeping expensive inductors in boxes which you will never use.
Great idea, thanks for posting that!
Best,
Mike
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A good trick I read somewhere is to use a multitaps power transformer(cheap), that will give you various values of inductance, once you determine the value, then get a high quality type.
this is useful, as you would not be keeping expensive inductors in boxes which you will never use.
Great idea, thanks for posting that!
Best,
Mike
You are welcome, I learn many tricks/facts/ideas from visiting various forums, the key is to use those which apply to you. There are many people contributing for the benefit of people like us. I am just doing my part.
Some care must taken as some of them are not quite accurate/true/misleading.
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I learn many tricks/facts/ideas from visiting various forums, the key is to use those which apply to you. There are many people contributing for the benefit of people like us. I am just doing my part.
Some care must taken as some of them are not quite accurate/true/misleading.
How do you sort that out? You're stating there are ideas that are true and applicable to one's specific application. Okay, I can grasp that. But then for the benefit of others, how do you sort out the ideas that are true but not applicable to your specific situation vs. the ideas that are bogus?
John
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How do you sort that out? You're stating there are ideas that are true and applicable to one's specific application. Okay, I can grasp that. But then for the benefit of others, how do you sort out the ideas that are true but not applicable to your specific situation vs. the ideas that are bogus?
John
[/quote]
As far as I am concern I will only put out ideas/tricks/facts that are technical correct like the mutitap transformer case, or suggestions/recommendations that I have direct experience with and found to be true and correct(I am not a politician). For my opinions only I tend to say, an educated guess, my opinion, etc.
For the suggestions/recommendations/"facts"/ideas from others I have no control over with, you have to read extensively to sort out the facts from fiction and use your own judgement to determine what is right or wrong or suitability and use them accordingly. Sometimes you use your gut feel to determine what is correct/suitable and try them out. Sometimes you think it is correct/suitable may prove wrong/not suitable.
I tend to be more cautious than others..Hope this clear things out.
hope this helps.
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I received my 4.7 mh coils and installed them today.
This is what I purchased:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=255-648 (http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=255-648)
The results are fantastic. The Alpha 15A integrated beautifully with the B200's.
Again, this is with the B200 wide open and just the coil on the Alpha 15A's. I don't think
I have ever had this quality and strength of bass reproduction in my system.
I am using the "Jeff Day" Walmart cables on the Alphas and some MIT T2's on the B200
which I will change out to a slightly brighter cable. Those Jeff Day cables are not broken in
and a little sharp on the top but they are a unbelievable tuneful bass cable.
The net result is a fuller, stronger, powerful B200 sound. I would never know I had 2 drivers
if I couldn't see the panels. I have great depth and detail and now solid tuneful bass. I didn't
have that in v1 with the 12MH coils I had around from a NHT 1259 system.
So for ~$200, cutting 2 holes and Richards advice I have taken my OB's
to the next level. I guess I now know why you guys have been talking up the 12" woofers
on the panels.
Thanks (again) Richard!
In the "lab" I am using a Vinnie 3950 and a Jolida 102B.
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Hi Jeff/JKelly ~
Ahhhhhhh... you have got it!!!!!!!!!!!!!!!!!!!!!
You and I are actually listening to the same speakers in essence... just wait... it really does get better.
Congratulations, Jeff... you must be in audio nirvana... and just in time for the holidays!!!!
I am actually convinced that the OB experience with our B200 and Alpha configuration takes a bit of time for the ear to adjust to... that incredibly deep level of saturation of layers of harmonic tone, the lightening-speed and transparency of the transients, the lush vocals that melt your heart into puddles of emotion, the scintillating detail that puts every nuance into your room as if it was recorded this very morning, the startling sense of immediacy that catches you off-guard... and yes... the beautifully fleshed-out bass that expands the foundation of the sonic musical language... that sense of wholeness, of completeness that gets across the intention of the musicians and singers and composers... and also the real spaces of the recording created by the subtle ambient reflections that flood your room as the music unfolds.
You saved yourself thousands... and the nightmare of ultimate disappointment... by your own creative efforts.
With this OB your amplifier choices and media source will reveal incredible differences to you.
Your audio life will never be the same.
Warmest Regards... and a marvelous holiday season to all! ~ Richard
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I have helped Richard to get photos of his baffle in this thread. Here are the pictures with Richard's comments.
'Here are a few pic's with comments below each pic that help to explain the structural elements of the baffles. I hope this helps
(http://www.audiocircle.com/image.php?id=12562)
Note the curved base... also the Alpha-15's are attached on the back... more about this to follow. The B200's are set-in flush to the 3/4"
maple plywood.
(http://www.audiocircle.com/image.php?id=12560)
Back shows the separate circular "ring" that the Alpha's are screwed onto... the screws for the ring are what you see from
the front as a sort of nautical "design" effect. Note the simple inductor sitting on the base... positive leads of speaker wire
hook up only... the negative leads tie to themselves (do not touch the inductor at all).
(http://www.audiocircle.com/image.php?id=12561)
Note the very narrow "wings" that attach to the inside of the baffle and also attach to the shelve on the top
and the base below... Jim designed this for structural integrity... I might have preferred another design solution
but Jim went ahead on this without our chatting about it and I think it looks just fine and does not seem to effect
the sound adversely.
(http://www.audiocircle.com/image.php?id=12559)
I stepped back on this shot... my main living space in this 1976 mobile
home is 20 feet wide by 26 feet deep... the OB's are on the right side
in the front of the mobile... the left side is our eating area... I took down
some walls when we first moved-in and made it into a loft style
large room.
Let me know what you think.
Warm Regards ~ Richard'
Well, I think these OBs both look and of course sound gorgeous !
/Erling
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Thanks Erling for placing the images of my latest OB baffles into this thread... very very kind of you... and also thank you for the kind remarks about its aesthetics... and while I am at it, thanks again for recommending the Alpha-15's to me... the most significant development in my OB life since I purchased my pair of B200's three years ago... and that was thanks to the good doctor Dan Mason... who is currently helping earth quake victims in Lima, Peru.
I want to report a very significant performance leap with these baffles... today I stuck 2 CD cases underneath the middle of the front baffles... raising both baffles 1,1/2" (one double plastic case and one single plastic case)... the performance change has been spectacular!!!!!!!
Aiming the Alpha-15 up in the front and down in the back has created a very very noticable improvement in the bass performance... I am talking about something very significant here... powerful bass presence that now gives a much fuller gestalt to the music. Also the "beaming" issues I had with the Planet 10 phase plugs installed in the B200's has disappeared entirely. Aiming the B200's upward seems to have fixed that problem.
But more importantly the music now has much more immediacy... voices are more noticeably alive... visceral.
For those that have perpendicular baffles do yourself a favor and try tilting them back. I don't know what 1,1/2" translates to in terms of degree of tilt... perhaps those highly skilled engineers in our community can figure that one out. But the effect is extraordinary.
Happy Holidays Everyone!!!! Warmest Regards ~ Richard
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Richard
that is the cleanest looking OB rig I have ever seen. Essence of DarkStar. The oil of Aphrodite. And the dust of the Grand Wazoo....
Yes, this is the OB experience rolled into one fantastic chunk of woodworking art - statement, a collision of arts, a veritable "Faculty of Arts and Crafts" ...everything we have learned about the outer fringe of DIY audio has been spun into gold by the obviously highly talented Jim. A statement on the Dark Arts. The dark star with its Jovian satellite. Each sphere in orbit of the other.
Anyone interested in OB should read Martin King's latest paper. www.quarter-wave.com about the most important thing here is that in considering bass drivers, and mains, ideally the mains be rated at least 6db less sensitive than the bass driver rating. I believe this is one reason why the Alpha and B200 get along so well... below 2KHz, according to my measurements, which gybe with Visaton measurements, is that the B200 is about 87db. I do not consider this a high efficiency driver, like the Fostex FE208, or Lowther, but the good news is that it makes it a dream driver to mate with larger diameter bass drivers. The way Richard has it set up is perfect. A coil is all you need, to low pass the bass driver. I find the mains never sounded the same, or as good when high passed. Run them full range as there seems to be some unmeasured, but clearly discernable difference, possibly psychoacoustic in nature, but the mains always sound best run full range. I have found that the equalizer that is part and parcel of iTunes has been the single best development for home audio, especially with open baffle. I shelve off the entire pass band, but add lots of db's in the lower register, and the 6 X 9 Kenwood single drivers will make plenty of bass, with very little IM distortion creeping into the midband, along the inner circumferences of the oval cone. They are good drivers, and respond well to contouring. I owe Vinnie for turning me onto iTunes. It has been a good thing. Hard disk drives are inexpensive. I brought two of them with me.
Yes, I am currently in Santa Luz, Lima Peru working with the World Health Organization, in an area that has been all but forgotten by the Western World, long after its newsworthiness has passed, it media value, no longer of value. What you didnt hear after the quake's one day news cycle, was that 50,000 were basically left homeless, and all together, stumbling around in several square miles of destruction, mothers, children, peoples parent. People's kids. ...people, with a government, and economy that is not capable the infrastructure necessary to dig its people out of this one. There are people from all over the world here, all are infidels, citizens of countries Al Quaeda would rather be here. My next door neighbor is a retired Canadian telecom engineer, and he is heading up the restoration of the wires, lines, and all that stuff. He is an inpiration, and study in living well. I am doing primary healthcare in the afternoon, and attending in O.R. in the mornings, at most four days a week. Three days are mine, and just so you dont think all this Schweitzerian, the food, the people, the art, the music, and the SURF are all world class. Peru has easily some of the most consistently fantastic surf on the planet, I like to surf, and I live ten minutes from the Left Coast. Every day we have big tureens of seafood chowder, rich broth teeming with shrimp, lobster, scallops, strange and wonderous vegetables, all seasoned artfully... I have only shifted gears, adjusted the "horizontal hold" on things. The ten days I returned to SD was during, The Fires, so that was ...interesting. Go home for a visit and get sick on smoke. My stereo consists of a pair of Kenwood single driver car speakers, on open baffle, with a Clari-T amp! It sounds fantastic. I should add that Bruce, the engineer from Ottawa, is fascinated by the sound of the speakers on concrete flavored plywood, and even more interested in the sound coming from the little black box, and has borrowed the stereo to use in his own place. A portable, community stereo.
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DM - represent! You make us proud.
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Hi Dan,
Glad you took your time to read and answer. I certainly also like Richard's baffles. Clean and straightforward. You are right in that a single Alpha 15 might well serve the B200. But you are wrong in stating the sensitivity below 2 Khz. In fact below 900 Hz the sensitivity is below 90 dB and the main point is how to tame the rising response above this point. Some like it as it is others do not stand it, it is a very personal reaction.
I think Richard has a very good point in his backleaning the baffles. He will be more in line with B200 on axis response and he might be helped a bit more with floor reflections and reinforcement in the bass. In fact this is also the good truth with OB's there are a lot more alternatives available to tune baffle response than with enclosures.
You are dead right about MJK's paper. This is essential reading for anyone interested in OB response. You can learn a lot if you read it and also figure out what you are actually reading.
/Erling
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Erling,
I agree completely. And I agree with Martin's sensitivity matching conclusions. I also notice that the original Japanese drawings for what is now known as the Joe Esmilla design, all call for about a 7' slant back, presumably to point the driver upward, but also to take advantage of boundary gain. I know the difference Richard is hearing. Seems the backward slant is mandatory.
About rising response, I believe that as we now have free access to very useful 24 bit DEQ by way of iTunes, people into OB should endeavor to use it. Equalization seems necessary to me at all times, but especially with open baffle. The B200 has a much different tone to it when you shelve off the rising response; likewise, I used it to lift treble response on my 1960s Coral 12 inchers. With contouring, they produce as much treble as I require, and it is amazing how little musical information there really is, over 4KHz. The Corals easily do 8KHz, which should be plenty for anyone with ears over 40. They also do real bass. Very nice speakers.
Backward slant of baffle, and active equalization using USB audio seem mandatory to me.
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Dan,
You are really tossing up good numbers. You are very right about 4 K, voices for instance will be covered to the 3rd overtone in this range, but again you would not really miss the rest of the frequency spectrum. And I should add I agree completely about 24 bit digital EQ possibilities that now are available. This works wonders. See I read to fast !
All the best,
/Erling
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The Inguz Squeezebox plugin has a very handy semi-parametric EQ that would be great for tweaking this type of response - no microphones or measurement needed. A ratshack meter and test tones might be helpful to target trouble areas though.
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Greetings Fellas, have just found this thread although I've been aware of mjk's article for a while, and I'm finding the prospect of trying my b200's with the alphas exciting. I have lived with my b200 in open baffle for about 1 1/2 years and have been very pleased with the result running in conjunction with a sub but lately Ive wanted to simplfy my rig by getting rid of the bi amping and run them off a single 300b amp as well as go totally ob as the sub was a br, and Ive heard horn and ob bass and br just does not compare. So I need some advice.If I were to run the b200 and alpha together I realize that the coil goes inline with the pos lead to the alpha but how does it conect to the b200, and what do I do if I want to bring down the volume of the b200 wrt the alpha(important note, all advice must be rendered in such a way as to make sence to a 6yr old as I know so little about series parralel blah blah :? Oh and what will be the final ohm of the ob so I know where to stick it into the back of the amp? The goodnews is that the woodworking side is a piece of piss as Ive already built three pairs of blh and these obs but unfortunately the wiring always stumps me.Hope to hear from you gentlmen peace and goodwill fergs
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Hi Dan ~
It is wonderful to read your energized and colorful prose once again. A marvelous infusion of fresh insights and fresh air in the often labored number-numbed world of audio. Of course we all have you to thank for starting the Dark Star thread several hundreds of posts ago, which has created this revolution in our thinking... and listening.
Jim McCarthy came over yesterday and was listening to some cuts he recorded of his son and his sons girlfriend singing Christmas songs, karaoke style... and we also listened to quit a few CD's. Jim is a composer, recording engineer, a musician (he plays in a band), a designer and a cabinet maker... he designed and built the OB baffles that Erling was kind enough to place into this thread for me. So he was actually hearing them for the first time. He wanted to let me break the new Alpha drivers in before a really good listen.
Jim is hard to please... he hears every anomaly in every recording and every speaker system... all those years of engineering recordings... which he still does... has left him with this highly critical ear.
Jim was quite taken back by what he heard. "I was wondering when you where going to finally get these OB's to sound really good... these sound fantastic... I am hearing things I never hear before on these CD's..." He was impressed to say the least.
I looked into your thoughts about ITunes having a built-in EQ Equalizer, Dan... It's fantastic!!!!!! You can learn a great deal about how an equalizer actually affects the sound with this nifty little tool. I am seriously considering buying a portable mac now and use it as my "CD player"... perhaps with a sound card for better fidelity. I will look into it very soon. Nice suggestion!!!!!
I hope you can pay a visit to Ojai when you return from Lima... I would love to hear your thoughts on these OB's and hear what your rig sounds like as well. Do take care Dan and happy holidays.
Warmest Regards ~ Richard
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Hi fergs ~
I will gladly share what little I know... but there are far more sophisticated minds contributing on this thread that understand the connectivity issues far better than l do.
I have speaker cable going from my amp directly to the B200's. From the B200's there is a short speaker cable that goes to the Alpha-15's... right now I have the exposed wire ends of the short speaker cables, going to the Alpha, wound around the exposed speaker cable going to the B200's at the + and - tabs. Each of the positive leads of that short piece of speaker cable wind around one of the 2 prongs of the inductor I am using: a simple wound iron core coil: Jantzen 3.9mH 14 AWG C-Coil Toroidal Inductor: 4.7 mH:(millihenry: a unit of inductance equal to one thousandth of a henry). The "negative" leads do not touch the inductor but go straight from the B200's to the Alpha's, exactly as you suggested.
I am driving both speakers with a Korneff 45 SET all tube amplifier: approximately 2.5 watts according to Jeff... with a preamp that has 2 different circuits to choose from... the all tube Peppard Magic 5... highly modified by Lloyd, for me, that has a gain of 20 db... those 2.5 watts are enough to blow Deb and I out of our house!!!!!
The integration of the B200's is seamless... quite magical. But if you want to be able to drive the Alpha's independently of the B200's you will need a separate amp... a plate amp with volume controls has been suggested by Dan Mason... or some device that boosts the volume of the signal coming from your amp before it reaches the Alpha's... such booster box's do exist.
But if you start to "adjust" the Alpha's to play louder (more gain) than the B200's... the seamless integration may be compromised. I ran the Alpha's independently at first with another tube amp that had tone controls before finally settling on using the Korneff to drive both the Alpha's and B200's in parallel. The SEP could go a bit lower... marginally... but there was definitely a trade-off in all-over integration... perhaps another kind of amp might have had better results. Still... the bass I am hearing is very effective. Jim was quite impressed... and that is saying a great deal!!!
My advice? Try the B200's and Alpha-15's without biamping first... and get used to the sound before making any purchasing decisions.
Now let's wait to read how the more knowledgeable AC members answere your question.
Warm Regards ~ Richard
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Fergs,
There's nothing expert about my opinions, but I can vouch that this setup works very well. B200 run fullrange with a coil in series with the woofer (mine is from a Hawthorne SI, which is very similar to Richard's Alpha) results in a very integrated and full range sound, without any crossover colorations whatsoever from 250hz up. I don't see any reason to attenuate the B200 because - frankly - it doesn't seem to need any. A resistor would do the job, though.
Which output terminals you use would depend on a couple things, but I think the best advice is to try the 8 and 4 (if you have one) taps. This determines what load is seen by the output tube (hopefully you use tubes), and this loading affects power and distortion of your power amp.
The impedance of these drivers in unison would dip in the crossover region, but is no problem for SET amps. I've just completed a SE2A3 amp (conventional design, only 3.5-4W), and it has more than enough power and drive for this speaker setup.
Somebody please correct me if I'm wrong, but wouldn't these drivers in parallel would have less of an impedance rise in the LF, and therefore easier to drive. Can somebody please verify?
Anyway, I encourage you to try this. It's amazing what flea-powered tube amps and OB can produce.
Thanks and best regards
Mike
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Mike
Regardless of how you chain the drivers, or not, the rising response is far greater than what would in my mind be attenuated by Z @ >6KHz. My measurements looked alot like Visatons. This is what Dave Dlugos' phase plugs are all about. Otherwise, again new thinking is in order here, and now we have FREE 24 bit digital equalization courtesy of Steve Jobs.
iTunes DEQ
At only one octave intervals, I first thought this feature was abit hokey, until I started playing around with the canned presets, which CLEARLY are well thought out and are ALL highly useable. I found for example a way of playing Jethro Tull's "Thick as a Brick," and this album is an example, a notorious album for fabulous writing and musicianship, and really, reeellly awful production, and iTunes saves it, for the first time.
WHat I have been doing is starting with around a 4db shelve from 0db and go from there. Note that they included a GAIN setting on the "pre amp" which now becomes highly useable, and gives you a free 4+db EQ headroom also for free. I come to home audio from Pro Audio, my first "real" summer job was as an all round gopher for Clair Brothers, and was assigned to the 1978 summer US/Canada tour with a little band from England known as "Yes." You learn things with a gig like that. One thing I learned was that active EQ was as essential to getting the most out of the room you have to work with, with the stuff you have to make music. Amplified acts would all sound uniformly like shit were it not for active EQ on several levels, from instrument mixing, to monitor mixing, to Front of House mixing, it is all EQd, and with OB, it becomes even more essential to my thinking, and home audio is definitely an amplified act.... and if using the B200, more important, but with the Coral 12s it is like alchemical reaction, and brings the actual tone of the Alnico magnets right up front and center. So I urge you to download iTunes and try it.
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Dmason,
Thanks for your post, but I'm not sure I follow. My comment was about the low frequency end of the FRP, not the highs. When the Visaton and Alpha in parallel, wouldn't the resultant impedance be flatter around 70-40hz than with either driver alone?
It seems counter-intuitive [to me] that two drivers together would be a flatter load...
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Greetings, hoping to get some answers about this project. This is my first attempt at speaker building and the the knowledge of all on the board is greatly appreciated.First off ,full disclosure I liked Richards speakers very much and have built something very similar.A question about the wiring of the inductor still remains.I have wired the feed from the amp to the B200 speakers. I then ran a wire from the + terminal of the B200 to one side of the inductor,the other side of the inductor has a wire that goes to the + terminal of the Alpha 15A.I then ran a wire from the - terminal of the B200 to the - terminal of the Alpha 15A. Is this correct?
My next question is about Tube Amps, I am looking for some recommendations having never owned one.
I would consider buying used to keep the price down. Also are their any solid state amps that are being used or some that would be recommended .
Thanks To All
Bill
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Yes - you have it wired correctly.
I am using this same system with a affordable modified Jolida 102b (EL84) and
really enjoy it. I have purchased NOS tubes which improve the amp dramatically.
Jeff
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Hi Centerfield24 ~
I have just received Vinnie Rossi's new Signature 70.2 monoblock amplifier... it uses the Tripath chip which is a digital/SS circuit... I have it combined with Lloyd Peppard Magic 5 SE tube Preamp. I intend to write a full report of my experience with this combination within the next 2 weeks here in the Open Baffle forum. However, I can say that nothing... nothing I have ever heard sounds like this combination... it is thrilling, utterly amazing!!!!!! and brings my OB's to life in ways I did not think possible. It raises the potential of my OB's to a level of resolution that has Deborah and I in a constant state of shock!!!!! Check out Vinnie's website Red Wine Audio:
http://www.redwineaudio.com/Products.html
Vinnie has a manufacturers forum on AC.
Expect a full in-depth report very soon.
Hi jkelly ~
I have heard great things about the modified EL 84 tubed Jolida... Dr. Steven Rayle who contributes to AC loves his... he is planning on sending me his modded Jolida in a few weeks so I should have a chance to hear what it can do for my OB's.
Warm Regards ~ Richard
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Jeff and Richard
Thanks for the response,looking forward to your report.
Thanks Bill
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I have to agree with what Richard states; I have heard NOTHING that sounds like the Red Wine Tripath Treatment into the B200 on open baffle. I state this in the first post of the DarkStar thread. I look forward to your sage assessment, Richard...
With the increased power available to you with the Signatures, if digital EQ is employed by way of iTunes, the amount, depth, and power of the bass available to you will be absolutely stunning.
For those contemplating an OB venture of their own, I have identified another driver that technically is perfect for home audio OB due to the fact that it is designed for open back small cabinet guitar amps, like Fender Princeton. It is the Tone Tubby 8, which can be seen and examined at www.tonetubby.com
I especially like its low Fs=50Hz, Qts=.707 SPL=93db, and nominal Xmax=2mm. Its response curve is flat from 50-5KHz, and it reaches easily to 9KHz, with little in the way of the usual rising response issues, which means tweeters are optional for many people. With the hemp cones there is almost no cone break up so 9KHz means exactly that. They can be had for under $80... we now have Hemp flavoured mains drivers for OB with specs almost too good to be true, for eighty bucks.
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I have just peaked at the response graph for the tone tubby 8". For both the 8ohm version and 16ohm there is a 16db rise in response between 900Hz and 3.5kHz. The price is posted as $90 each.
The speaker appears really flat between 50Hz and 350Hz.
I haven't seen many speakers which such a flat graph to 50Hz.
It looks like it would be good with a 2" or 3" wide ranger crossed at about 350Hz.
I wish there were graphs for the 10" and 12" tone tubby's.
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I have no idea, but I am thinking the rising response may be just a function of the fact that it is intended for pro audio use and the measurements are in 4pi space (as opposed to 2pi).
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If we knew the LE of the driver, it could be modeled. I emailed them and hope to get a response.
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Edit: Oops-If you were not talking about the Alpha 15, ignore this post.
The info below is still useful, though, to anyone who didn't know where to get Eminence data.
-- Mark
If we knew the LE of the driver, it could be modeled. I emailed them and hope to get a response.
Le is 0.84 mH.
Complete specs for all Eminence drivers available thru www.Eminence.com
They are also great about listing the Xlim or Xmech (driver travel before actual damage) for all their drivers, not just the Xmax ("controlled" linear excursion). Many manufacturers don't like to provide this info.
Xlim is a helpful spec because if the Xmax and Xlim for a driver are nearly the same, it's more likely that you can accidentally damage a driver on an OB without warning.
In the case of the Alpha 15, the Xlim is more than double the Xmax!
--Tubamark
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I was referring to the Tubby, Mark. It looks very good on paper, (monitor), but the ability to model it would pretty much seal it for me.
I haven't heard back from Brown Soun with the LE spec. Without it, I can't model it. Without being able to model it, I won't buy it.
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Hi Mark ~
As an Alpha-15 user... your important information:
"In the case of the Alpha 15, the Xlim is more than double the Xmax!"
is marvelous news!!!... thanks for posting that Mark... it seems that Eminence has built a high
level of performance into that driver!!!! In fact... I have yet to actually see it move while
music is playing... and the bass is incredibly effective... pitch perfect and viscerally "present".
Warm Regards ~ Richard
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Can I ask what material you've used in the baffles on page 5, and in what dimensions?
I'm considering to start a similar project myself. Cheap, easily available parts, simple woodwork. Just my type of diy project. aa
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Hi
Can someone give me a link to the MJK papers?
Many thanks,
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http://www.quarter-wave.com/OBs/OB_Design.pdf
G.
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I was referring to the Tubby, Mark. It looks very good on paper, (monitor), but the ability to model it would pretty much seal it for me.
I haven't heard back from Brown Soun with the LE spec. Without it, I can't model it. Without being able to model it, I won't buy it.
Markc, you can model the Tone Tubby fairly accurate without the Le spec. The TT is a guitar speaker good for 5kHz and beyond (some people use them as regular speakers without tweeter) so my guess is that Le is not significantly high. Also, common sim software does not even take Le into account.
BTW, Lynn Olson has published some mlssa measurements on the 12" inch AlNiCo TT on his website ( http://www.nutshellhifi.com/MLS/MLS6.html (http://www.nutshellhifi.com/MLS/MLS6.html) ). It definitly looks like a interesting OB contender.
Regards,
Jon
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I like to use a spice program to model and I would definitely require the Le. Sadly, I've had no response to my queries from Brown Soun.
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I was referring to the Tubby, Mark. It looks very good on paper, (monitor), but the ability to model it would pretty much seal it for me.
I haven't heard back from Brown Soun with the LE spec. Without it, I can't model it. Without being able to model it, I won't buy it.
I measured the free-air T/S #s for a pair (the AlNiCo 12", to be clear) and came up with .177 and .191 for Le. All the other numbers were in the ballpark of what they have posted.
Regards,
John
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I have auditioned both 10 & 12 Tone Tubby Alnicos, and they are spectacular on open baffle.
The combination of the hemp cone and Alnico magnet puts them in their own league, entirely. With the 10, my favorite, when I used active contouring, I could wrench all kinds of treble band information from them. My ears are perfectly happy with frequency extension to 9kHz, and the TT 10A did the trick. I can highly recommend them to you; these drivers are designed for open back cabinets, so open baffle is just a continuation on that theme.
If you tried the 12 mounted in the JE Labs configuration, a simple 1- order filter for your choice of tweeter, with attenuation, you would pretty much be guaranteed success; it has a nice low Fs, which, when combined with its ability to move some air, and the boundary gain offered by the JE mounting-level, it picks up lots of lower register. www.nutshellhifi.com MLSSA Gallery and would therefore be very easy to tie in bass drivers. These are my favorite new production open baffle drivers, based on what I have heard, and their simplicity in implementation. They can be ordered sans dust cap, TT can provide measurements associated with designing a phase plug, which can be made and installed, to complete the picture.
A++
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Markc:
Yes, I understand your concern. Some comments though, the inductance formed by the electrical equivalent of the mechanical compliance will be magnitudes higher than the voice coil inductance. Also, the dc resistance will dominate the impendance over the mid range while phase angle will move asymtotically towards 45 degrees in the upper range.
Yes, if you're going to do optimized crossover design I can understand that you'd like the exact Le value (along with error margins). If not I believe you can get satisfactory results just picking a fairly general (guitarr speaker) value of Le lets say 0.5 mH.
Anyway, i hope you'll get you answer from Brown Soun. Good Luck =)
Regards,
Jon
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Dmason:
Awesome! I've sketched/modeled on some OB TT designs during the winter but I haven't really heard about any succesful builds. Its incuraging to hear that the concept is usable. You dont have any pics or additional info?
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iON
Unfortunately I don't own a digicam, twice I have looked into them, and was abit overwhelmed by the "learning curve," as to what I should be looking for. Now, I wish I had gotten one several years ago...
As for modelling, either of the Tubbys will play low enough that bass implementation is easy. There is alot of effort going into designing exact crossovers, passive solutions, where active solutions are better in my mind, and easier. First, with a driver as sweet as the Tubster, they sound best with flea powered single ended tube amps, and 2 watts will blow your doors off here. Use of some sort of "pre amplifier" with dual outputs will allow one to use leads into the flea amp employing a shunt cap at the appropriate Fs to relieve the outputs and mains drivers of all lower register signal, a happy thing for both, which optimizes the situation on an order of magnitude far beyond spending mo' money for "better stuff," ...Second, just about any narrower width baffle will allow a "larger" diameter cone to roll in the magic 180Hz area, which then makes the use of a pair or two pairs of bass drivers, powered by high damping factor switching amplifiers, with their low pass adjustables, really easy to contend with. You sit on the floor with a drink, and tweak levels and passes until it sounds right --to you--
As far as getting additional measurements from Tone Tubby, do not agonize over the likelihood that these may not be forthcoming; they do their measurements independently, and more importantly, these guys are tuned into the guitar end of things. They are wooly Bay area rockers who aren't very concerned with audiophool measurements, because it is "fringe element" stuff to them, in their own words. (is anyone surprised that the invention of HEMP cones took place in Sonoma County?) the blessing here is that they found out a way to make something amazing out of all that lumber that wasnt making it into the final product. Next will be high grade machine oil made from the seeds :lol: but I digress...
My OB design will employ a pair of Lambda IB15 bass drivers power by BASH plate amp or two, and separately powered Alnico 10, with a phase plug, which, with the proper measurements of dust cap width, distance from pole piece to cone circumference, can very easily be turned on a lathe. It aint rocket science, just a good thing to do, especiallyl with a larger diameter cone, whose beam-point is fairly low, dont know what it would be, but likely in the area of 4kHz with the 10" ... I feel success coming, with a baffle of 18" wide, by no more than 33-36" high, and possibly a little tweeter just to fill in some audiophool-approved "air."
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My OB design will employ a pair of Lambda IB15 bass drivers power by BASH plate amp or two, and separately powered Alnico 10, with a phase plug, which, with the proper measurements of dust cap width, distance from pole piece to cone circumference, can very easily be turned on a lathe. It aint rocket science, just a good thing to do, especiallyl with a larger diameter cone, whose beam-point is fairly low, dont know what it would be, but likely in the area of 4kHz with the 10" ... I feel success coming, with a baffle of 18" wide, by no more than 33-36" high, and possibly a little tweeter just to fill in some audiophool-approved "air."
Sounds really nice. Any idea of a matching tweeter that can be used with a simple crossover? Kind of like Bastani's directly coupled wideband and tweeter with series capacitor? I'm a total newbie with crossovers (more of a dac/amp guy here), but to me it looks like the tone tubby can be combined with the Eminence woofer like the Visaton as the efficiency is somewhat in the same range?
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......Kind of like Bastani's directly coupled wideband and tweeter with series resistor?
should read tweeter with series capacitor...
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......Kind of like Bastani's directly coupled wideband and tweeter with series resistor?
should read tweeter with series capacitor...
Sorry. I got it messed up. Corrected it now.
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Hi painkiller,
The B200 already goes quite high, but it is not coherent and the HF beaming can lead to HF reproduction sounding a little dry/harsh.
I do not have shelves full of moden tweeters to try with the B200, besides, few of them would be sensitive enough. Piezos sometimes work surprisingly well at HF, though these cannot be assumed to do so equally with all amplifiers due to their capacitive nature.
My personal choice for HF augmentation with the B200 is the cheap and cheerful Eminence APT without any horn; it has sufficient efficiency above 15kHz to be useful.
With a 22 ohm damping resistor connected across the APT terminals and no more than a simple series feed capacitor it can smooth the B200 harshness and recover a liquidity of reproduction which might not even be known to be missing until the APT is disconnected. The effect is very subtle, and although the APT output is barely noticeable on its own compared to the B200, it is most worthwhile.
The series capacitor might be anything between 0.22uF and about 0.5uF according to personal preference, so I would suggest purchasing 1x 0.1uF and 2x 0.22uF per side in order see which combined value sounds 'best'.
The most important aspect when adding a tweeter is time aligning the driver dustcaps. When simple crossover circuitry is being used they must all be at the same distance from the listening position.
With the APT this means that its horn opening must be level with the front chassis edge moulding of the B200; just 1/4" back/forwards and the reproduction will not be improved, and the inaccuracy of time aligment cannot then be compensated for by adjusting component values or reversing tweeter phase.
This is why a plain surface mounted cone or dome tweeter will not help the B200, no matter how perfect or expensive that tweeter might be !
The correct position for the APT means that its pointed phase plug will protrude beyond the baffle, and there will be HF diffraction too. This is normally unwanted, but when used with the B200 it improves off-axis HF reproducion as well (if not the beaming).
Cheers ............ Graham.
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Dmason, thank you for your lengty reply!
That active TT10 + IB15 sounds like a good recipe! Btw, You know that AE speakers have a 15" specialized for dipole use as well? Cant seem to find it on the home page but I know they posted info about it in some forums.
Regarding Tone Tobby, I think they're cool to deal with, when I mailed them about shipping to Sweden I got a quick response that it shouldn't be a problem. Thats good news, since the dollar is so low I think buying stuff from over seas can be justified :wink: . Btw, have you used the 8 och 16 ohm version of the tubby?
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This is the one I was referring to in the previous post:
http://web.archive.org/web/20040307231755/lambdacoustics.com/drivers/DIPOLE15.html (http://web.archive.org/web/20040307231755/lambdacoustics.com/drivers/DIPOLE15.html)
Some info:
http://www.aespeakers.com/phpbb2/viewtopic.php?f=3&t=892 (http://www.aespeakers.com/phpbb2/viewtopic.php?f=3&t=892)
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I'm sorry for being unclear. I was actually talking about a tweeter for the Tone Tubby driver, but I guess that's way off topic. Maybe we should move the discussion to a separate thread as there seems to be some interest for this TT AlNiCo driver.
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Back to B200 & Alpha-15A combo...
Has anyone compared the Jantzen c-coil toroidal to their copper foil inductors in this set up?
Jantzen advertises the c-coil inductor as "specially engineered for bass, sub-woofer..."
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Sorry iON, I didnt notice your post/query..
I sampled the 8 Ohm Tone Tubby 10, but I would think that the 16 Ohm version paired with a small 16 Ohm tweeter of some sort, and a tube amp with 16 ohm taps would be pretty hard to beat. Either way, they are insane sounding speakers. John Harrison invented something special in these things. Makes me wonder what the 15 inch SuperBoy bass speakers would be like, the Alnico 10 on top of that, and some little horn tweeter, or ribbon. I believe the 10 inch to be superior for a mains driver of hemp, and it reaches nice and high.
Probably something like the AE 15 would be the idea candidate; those guys know what they are doing and are synonymous with super high quality stuff.
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I simulated TT 10" Alnico 8 ohms on an 40 x 20 " baffle with MJK's worksheet. It was placed 34" high and 8" in from the side.
This is the result:
(http://www.audiocircle.com/image.php?id=15074)
Pretty impressive !
/Erling
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Hi Scorpion,
Could you generate the same graph for this driver?
http://www.shredmuzic.com/product_p/813-018.htm
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I would recommend everyone interested to use MJK's MathCad worksheet. The fee is only nominal and you can do with the free MathCad version.
It is real fun ! I did the Tone Tubby simulation because I thought that this was of some general interest as discussions of these Alnico units have been hot lately.
However, Jeff here is the simulation of the Warrior 10, same placement as TT above:
(http://www.audiocircle.com/image.php?id=15076)
/Erling :)
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Mistakingly put here, should be and is in the 'New insights ......' thread.
I measured the Alpha15 fullrange in my 'Volks-OB' mic at 1 m distance and 90 cm (36") above floor in my livingroom. This is the result:
(http://www.audiocircle.com/image.php?id=15090)
Quite astonishing, nothing of the cone breakup. In fact it is quite pleasant to listen to fullrange. The fundamentals are well reproduced. So revision is called for !
I think Richard might have a very good case when complementing the B200 with the Alpha going higher. As Martin said, you should never rule anything out beforehand. :oops:
/Erling
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Hello,
and what about dispersion in full range listening ?
This is my first post here, I'm also thinking to make an OB design, but a 15" driver won't have WAF agreement, so I need a 12" one, and a cheap one just as alpha 15. Do you think this 12" driver could perform well in OB design ? It looks like a 12" tony tube driver, not the alnico one ; here it is :
http://www.toutlehautparleur.com/fane-pro/fane-sovereign-12125-p-2371.html
Scorpion, would you mind to simulate it ?
Thanks
:wink:
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androuski,
See my answer to Jeff above. MJK's software for simulation, obviously the best there is, can be obtained for personal use for very little money. Recommended ! : http://www.quarter-wave.com/ . It shouldn't be misused as a lot of work definitely has gone into the worksheets.
A software like Xlbaffle can also be used for simus, certainly not as accurate, but available free: http://www.exdreamnet.de/download/Xlbaffle.xls .
The Alpha15 is listenable fullrange but I would not recommend its use as such, there are much better. But Richard's use of it as a complement to B200 might just hit the nail.
All the best,
/Erling
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Mistakingly put here, should be and is in the 'New insights ......' thread.
I measured the Alpha15 fullrange in my 'Volks-OB' mic at 1 m distance and 90 cm (36") above floor in my livingroom. This is the result:
(http://www.audiocircle.com/image.php?id=15090)
Quite astonishing, nothing of the cone breakup. In fact it is quite pleasant to listen to fullrange. . . . <snip>
Seems too good to be true! Any chance you did (or could) measure it for us at a more typical listening distance - say 2.5 meters?
As measured above, we're getting the response at ~45 deg off-axis . . . I'm curious what might appear when listening from a typical listening distance, which puts the ears only ~10-15 deg off-axis (for a vertical baffle), and nearly on-axis for a tilted baffle. Also, baffle effects are not fully developed at 1 meter.
Keeping my credit card in my wallet just a little longer :lol:,
-- Mark
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Just completed my version of the Visaton B200/ Eminence Alpha.
Baffle is 20" x 40" x 1.5" with a 7 degree slope.
I appreciate that the baffle my be a little less wide than some are using, but in order to have it domestically acceptable, I went with as wide as I could to have it fit the room and be domestically acceptable. So far it has only been running for a day, and have tried 1,2,3 mH on the Alpha, but at this time it actually sounds better with no inductor and run fullrange. There is however some ever so slight "honkiness" and I suspect that this is due to the Alpha being run too high.... so lots more to do, but will wait until they have been run in a bit more.
.
(http://www.audiocircle.com/image.php?id=15105)
.
.The overall sound and tonal balance is super, however, but there is a distinct lack of bass in my 12' x 17' room and I have listened with both SS and tube and it is only with some bass boost, courtesy of tone controls(yikes!) .....then I can get it very well balanced with the bass boost. I guess that this is to be expected, though it is not quite the impression that I have got from reading through these threads.... must read them all again however! I dont think that the baffle being just a few inches wider would make much difference in the bass in real terms.... unless someone can tell me otherwise
In retrospect, I was thinking of using two Alphas per channel and decided that one would enough - seems that my gut instinct would probably have been a better route to take.... hey, but at least I am half way there now.
Any comments good or bad would be appreciated
Derro
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Hi DerrO,
Beautiful looking baffles, really an eye catcher in the room. I think the width is just fine.
I think you might have given up a little bit of bass by mounting the Alpha 15A that high on the baffle. The bass driver should be mounted as close to the bottom of the baffle as possible to maximize any help from the floor refection. That may or may not have made enough of a difference, the B200 may be just a little too efficient to get away with only one Alpha 15A if you are using a passive crossover.
Martin
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Hello MJK,
Thanks very much for the input and you have just confirmed the two things that I feel i did wrong - namely, too high a position of the Alpha and also using just one with passive as you say. It is the comment that I didnt want to hear - but the truth always hurts!
Actually, when I first tried the Alphas when I got them, I did just put them on the floor and was quite amazed with the bass and I feel that I have less bass now with them in baffles than when I initially tried them on the floor - with NO baffle at all!!!!!!! - go figure!!
SO I guess that it is now l need to try again doing what you said. Oh well, at least the Alphas are cheap..... the time end effort making another pair of baffles, is not! Still, it will keep me off the streets!!!!
Thanks..... but ... in the immortal words - "I'LL be back!"
DerrO
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I am using the 4.7 mh coils:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=255-648 (http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=255-648)
and doubled up Walmart white extension cord cables!
Jeff
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DerrO,
Beautiful baffles ! I think that 6" wings might do the trick. Just try with two cardboard sides at the back and see what happens. Then we have the rising B200 response and the perceived bass-loss is presumably a function of this phenomenon also. My first try with the wings in place would be to let the B200 run fullrange and put 3 mH in series with the Alpha and 10 uF across it or just a 1.6 mH inductor in series and see how that is liked. It is probably not optimal but a good start.
/Erling
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Hi Sccorpion,
Thanks for the kind comments. Yes, I will try side wings - though that is something I did want to avoid - but worth a try. I have no objection about using two Alphas, or spending the money on them but I just dont fancy doing the woodwork all over again! I have the inductor and cap you suggest and will also give that a try.... still dosnt tackle the rising response of the B200 though does it?!?!?! Any suggestions on that?
Thanks for your input.
Derro
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Mark,
I think you have a good point. Here is the measurement 2.5 m distance and 90 cm above floor for the mic. Also it is with high 1/24 octave resolution so it looks a bit ragged and exaggerated. The resolution is just to prove that the 50 Hz roomresonance in my measurements is very narrow and probably not heard at all on normal music. You are not that sensistive to bass-variations anyhow. This is the plot:
(http://www.audiocircle.com/gallery/albums/userpics/50000/Alpha15%2C_fullrange_2_5m_90_cm.JPG)
Now we are seeing a build up around 2 kHz so it is there, but it just a bit more prominent than other buildups. However the Alpha fullrange is not bad at all soundwise. I think one could refer to Hawthorne's Silver Iris which is an Alpha15 adapted to Eminence's American Standard Coaxial magnet assembly. If I remember correctly its crossover to the treble takes the form of a notch filter around 2 - 2.5 kHz and then using the normal roll-off of the unit. I think the Iris proves that Alpha15 can be used well up in the midrange with success.
/Erling
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DerrO,
In fact it might help with the rising B200 by letting the Alpha complement it to above 1 kHz making the combined response more in line with B200's response from 2 kHz and upwards all the way to 10 Khz. The combination should be experienced as better balanced.
/Erling
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DerrO,
Your baffles are very nice. :thumb:
How about trying a single Alpha 15 or a 15" Hawthorne Augie in a small H baffle with a plate amp to augment the other 2 15" drivers?
http://www.hawthorneaudio.com/catalog/index.php?main_page=product_info&products_id=19&zenid=rri4nbao4h17d2jhptmue7brg0
Lin :)
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DerrO,
Lin's idea is a good one, that would in effect be like adding a second Alpha 15A to your baffle without having to rebuild. The speakers look so nice I would hate to see you start over.
Erling's idea to add some temporary wings is also a good thought. This would in effect simulate a wider baffle. Don't be afraid of adding 12" or 18" deep wings. Wings do not generate resonances as is often reported. See if the bass or tone changes and adjust the temporary wings to optimize the result.
The other thought I had concerned how close you set up the speaker to the rear wall. Maybe moving the speakers a bit further into the room might help bring out some more bass. The rear wave bouncing off the rear wall and adding destructively to the front wave might be part of your problem.
Martin
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Those are super nice looking baffles! Great work.
I can understand why you would not like to add side wings - the baffles are so pretty, the wings could only hurt.
Sooo.... Maybe glass or plexiglass wings. :thumb: Just try some cheaper materials first, to see if it works for you.
The hot mids and highs from the B200 are probably what is causing the subjective lack of bass. Get them down and it's going to sound a lot more balanced.
Very nice work, I'm jealous!
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I think Martin and I talk about wings 90 degrees to the main baffle. They will be almost invisible from the front if placed just to make room for the Alpha. We had a discussion about this kind of back-wings. Martin argued the theory and I have complemented with measurement of two different bass-baffles to prove the point. There will be no resonances. :)
/Erling
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Many thanks to all for your kind words and thoughts on this.. Yes, I will try wings and the idea of clear perspex would seem to be a great solution as I would not loose the overall appearance. That said, over the next few days I think that I will just have to throw together some kind of baffle and mount the Alpha right at floor to determine just how much that is effecting things.
That said, given that I am using MacBook/iTunes/Apogee DUET DAC, means that I can dial in a certain amount of bass with the iTunes equalizer without detrimental effect. and I may be able to recover the missing bottom with this.
Thanks agin....
DerrO
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DerrO:
Gorgeous. After finishing your next baffles, please auction those pictured. Make it a silent auction. Notify only me to bid. :wink:
Lowering the Alpha to the floor + small wings will buy you maybe 3 db - still worth trying, of course. I would suggest triangular or curved rather than rectangular wings - more stealth.
I think that right now the sensitivity mismatch is going to obscure other factors, but still think that some Alpha filtering is warranted due to significant beaming that will be occuring where the 2 KHz bump is . . .
Before going to all the expense and time for new baffles and more drivers, why not "try before you buy"? : Put a test L-pad on the B-200, and set it to attenuate 6 db. That will give you a very good idea of the relative balance that will result from adding an additional Alpha 15. Then tinker with inductors.
It is also possible (gasp) to install a permanent L-pad on the B200 and leave it at that. I know that purists (often self-titled) will poo-poo this, but c'mon guys - the tradeoff here is certainly no worse than the "sins" already commited: all drivers run in their beamy range, etc . . . We're already playing outside the box here (pun intended).
Another free experiment: Hook the B200 to the right channel amp, Alpha + inductor to the left, play a mono source, and use balance control to experiment with driver balancing. Quick, dirty, and free experiment that can only lead to enlightenment :notworthy:. I think you will be surprised.
Try & let us know what you discover.
-- Mark
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DerrO,
Add Mark's suggestions to your list of things to try and you have an excellent set of options that will undoubtedly improve the performance of your B200/Alpha 15A open baffle system. Try them all and let us know which is most effective and what combination provides the highest level of performance.
Martin
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Mark is right - as Martin points out. Some very good options there for you to try.
Bringing that B200 down a few dB is the 1st step.
OT: Mark, how did my cat get into your speaker box???
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Or, indeed, my cat ! I do like that picture ! :D
/Erling
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I have studied the Silver Iris crossover, it is centered at around 3.1 kHz. If you instead try .5 mh, 10 uF and a 10 ohm/10Watt MOX resistor in parallel all in series with the Alpha15 plus connection, I think you might hit just the right frequency to cross between the Alpha and the B200. Then it is just the matter of matching levels. :)
/Erling
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DerrO
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Greetings Derro, really enjoyed reading your website, thanks for sharing.I think its already been echoed but if you can bring the baffles out further to about 1 meter you will be richly rewarded 8).what inductor did you end up using on the alpha(mH?).The baffles look fabulous, mini 909's. one thing to keep in mind is that cenral rear brace is the perfect opertunity to magnet mount the drivers which has a huge effect on reducing baffle vibrations especcially if you place soft rubber srtips under where the speaker is recessed into the baffle(you'll have to increase the countersink by the thickness of the rubber strip.Surpringly this has a very marked effect of stabilizing and improving imaging and sound stage. I have heard the difference with my mag mounted b200 on Mr Content baffles as developed on the decwaree open baffle thread. Look forward to any other developments with you baffles.
peace and goodwill fergs(been openly baffled for nigh on 3 years now,no turning back)
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DerrO and others, would substituting a 4ohm alpha version for the 8ohm version I assume you are using increase the alphas sensitivity thereby making it a better match for the B200 as I see you are trying to achieve.
Thought I'd suggest this since I have the 4ohm versions on order to go with my B200s, last two I can find in the UK due "lack of demand" as the supplier told me.
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I've never seen a 4R Eminence Alpha 15. I'll have to look around at US distributors, because if this is available I would definitely order a couple pairs.
Regards
Michael
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DerrO, I really enjoyed reading your page. What happened to the link?
Were you running both B200 and Alpha off your 300B amp?
Max
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Hi,
I removed the link as it was deemed to be a breach of forum rules. Yes, i am running the Visaton and the Alpha directly from the 300B amp. Still working on it and the Visaton requires a lot more burn in time - leastways I hope that it what it is as it has a bit of an "edge" - a bit "spitchy"!. Also I have not settled upon the value of the inductor for the bass unit as running this too high up the frequency range is causing smearing of the image as it is giving me some of the midrange like I have from the Visaton and the result is somewhat disjointed.
Actually tonight I tried the Eminence Beta 12 LTA in place of the Visaton with an added temporary baffle piece on top of the present one and the sound was glorious. Prior to this I was using the Beta 12 LTA/Fostex FT17H in a reflex cab. and I loved everything about that. So I can see myself at the very least making a proper baffle to test this setup. Actually I am more impressed with the Eminence Alpha than I am with the Visaton!
DerrO
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DerrO,
The Visaton is as it is, thats why many people go far to cure its rising response. The thing you should try first is the simple BSC-LR circuit consisting of a 1 mH (air-wound) inductor and a 10 ohm, MOX or any other non-inductive, resistor connected in parallel in the Visaton's plus lead. This will gradually shelve the response from a bit under 1 kHz reaching a full effect at about 2 kHz. Have a look at the Visaton NoBox filter: http://www.visaton.de/bilder/weichen/gross/noboxbb_w.gif. This will definitely give a more balanced response in the combination with the Alpha15. If you read through some of the threads here about the B200 (and there are some !) you will see more tricks to come on speaking terms with it, but the BSC-LR is the simplest and should be tried first to see how you like it.
/Erling
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Dear OB guys,
Iam very impressed with this old thread, seems the ALPHA15A and the B200 are a perfect pair through ?? I do not listen no one of them yet.
One thing caught my attention, all OB projects here are one ALPHA and one B200 only.
So, I wonder if two ALPHAS and one B200 could work fine?? Or even better than just one ALPHA and one B200 ??
An poster in this thread was using just a simple 4,7mH coil as ''xover'', but now in 2009 do you think this is a good sound option??
Is there any better filter option?
Someone has made an OB with two ALPHAs and one B200??
Thankyou for your comments or sound impressions about his OB set.
Regards, Gustavo
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I have not tried the B200 with 2 15" alphas, although I may in the future.
I think the driver balance is perfect now.
All I can say is Richard has put together an incredible combo.
My version with a highly modded NOS Jolida 102B is still the reference system
for all the new stuff I am building. For me - it is all about tone. And this is rich.
It won't have super bass or super highs. It will draw you into the music.
There was much work done on this system a few years back and I would
highly recommend anyone giving it a try.
Jeff
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Thanks for your input JKELLY.
Do you think one ALPHA and one B200 needs how many tube watts for a Hi SPL drive??
Looks two ALPHAS could have a big bass output?
I would like to xover cut in 600/700Hz this is too Hi?
Gustavo
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Not sure you need to go as high as 600-700hz with the bass, I found the best integration around 270hz. The B200 comes down to that easily. You will find the B200 is not well equipped for high SPL, it will do it OK, but will loose its smoothness. I do most of my listening around 95-100db. My 2cents worth anyway
Mr C aa
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Thanks Mr.C for help. I see in B200 Freq. chart the 270Hz point it already is in low low SPL, so I was think I could be better cut in 650Hz...
Looks the final tuning is by the ear, after listen both options.
Sincerely, Gustavo
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Yes I get where you are going with your setup, as I dont worry about high SPL, I have never tested those . Good luck with your system, keep us up to date with your progress. :D
Mr C aa
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I ran mine with a 4.7 foil inductor to the Alpha which cuts the sound around 275 -300 hz.
and full signal to the B200's.
I think Richard changed his inductor to have the crossover at 1000 hz. I never tried that.
If you are interested in running 2 alpha's - take a good look at the Anagram project by /Erling.
I am very pleased with mine.
Jeff
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If you are interested in running 2 alpha's - take a good look at the Anagram project by /Erling.
Thankyou Mr.Kelly for these infos. I was complety unware of the Anagram project.
As a Bass lover I think I will like of two Alphas in parallel for 4 ohms, more one B200 (6 ohms). Seeing the Alpha15 Freq chart, I fell 1000Hz is too hi for the Alpha, 15 inches is a big cone for 1K hz frequencies. I stay with 300 Hz or 650Hz.
Cheers, Gustavo
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I ran mine with a 4.7 foil inductor to the Alpha which cuts the sound around 275 -300 hz.
and full signal to the B200's.
Mr. Kelly, I forgot to ask you what is the AWG of your inductor? By your tests the biggest AWG coil is better?? or no?
The Jantzen 4.7mH AWG 16 is $37 at PartsExpress, do it is a good brand??
Thanks, Gustavo
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I have this one:
http://www.parts-express.com//pe/showdetl.cfm?&Partnumber=255-648 (http://www.parts-express.com//pe/showdetl.cfm?&Partnumber=255-648)
I'm not a crossover guy, but If you use 2 Alpha's (4 ohm) you might have to change the value
of the inductor to keep the same cutoff point.
Again I think the level of the single Alpha matches the output of the B200. If you run 2
Alpha's they may have too much output and overpower the B200.
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I have this one:
http://www.parts-express.com//pe/showdetl.cfm?&Partnumber=255-648 (http://www.parts-express.com//pe/showdetl.cfm?&Partnumber=255-648)
I'm not a crossover guy, but If you use 2 Alpha's (4 ohm) you might have to change the value
of the inductor to keep the same cutoff point.
Again I think the level of the single Alpha matches the output of the B200. If you run 2
Alpha's they may have too much output and overpower the B200.
Dear Mr.Kelly, Thankyou for your precision info. :thumb: After your statement I will can not use two Alphas, because of a probable imbalance in power and SPL. Well, back to the board.
I was want use two Alphas cause Iam afraid of short speakers, low in height, could have a soundstage low, near the room floor only and the soundstage do not rise hi in the room.
I wonder if your Alpha+B200 have the soundstage near the room floor only?? or it spread in all the room?
Thanks, Gustavo
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Dear all:
HiHiHi, I'm new & feel great to be here as i can find lots of info, too bad, i only realized this forum after i've done my OB. But it's never too late to know you all & learn from you all. :D
I'm currently using this on my open 2.5" thick, 20"x52" baffle, baffle made of plywood & teakwood:
Fountek NeoCD2.0 Ribbon Tweeter, Visaton B200, 2pcs Eminence Delta 15A.
B200 coupled with the ribbon tweeter with 1.22uF capacitors powered by 2A3 amp. 4 woofers powered by 4 channels Tripath 2020 amp.
I'm currently using Behringer DCX2496 as active crossover to play this setup in this configuration:
1st Output: Left Mid & Hi (1st order 200Hz to 20kHz)
2nd Output: Left Upper Woofer (4th order 20Hz to 200Hz)
3rd Output: Left Lower Woofer (4th order 20Hz to 200Hz)
4th Output: Right Mid & Hi (1st order 200Hz to 20kHz)
5th Output: Right Upper Woofer (4th order 20Hz to 200Hz)
6th Output: Right Lower Woofer (4th order 20Hz to 200Hz)
Is there anything wrong the above?
After briefly read through this thread & some other OB related threads, i found that my B200 has a peak around the region of 2 to 4kHz too? Any B200 users here experience this & what's the better solution to overcome it?
Anyone here using the DCX2496 too who can advice me how to configure the setting on the DCX2496 to overcome the peak?
Any input is much appreciated.
Thank you very much.
Some photos:
(http://www.audiocircle.com/image.php?id=22192)
(http://www.audiocircle.com/image.php?id=22193)
(http://www.audiocircle.com/image.php?id=22194)
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Benzene!
Really nice setup :thumb:
Regards
Kludden
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Kludden:
Thanks, Kludden.
I'm still learning & getting the sound right. :)
Cheers.
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B200 going full range from 200-20k Hz, joined by the ribbon tweeter somewhere in between? Wouldn't it be better to have a true passive crossover between the B200 and the Fountek?
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B200 going full range from 200-20k Hz, joined by the ribbon tweeter somewhere in between? Wouldn't it be better to have a true passive crossover between the B200 and the Fountek?
Agreed . . . (Gorgeous setup, though--lots of potential). Also redundant to have two extra channels of processing for the Woofers, XO'd identically.
This arrangement could be useful, however, if the slopes/XO points are changed (for example, lowering XO on the bottom pair, or raising on the top pair) for tonal balancing -much better than regular EQ'ing -- VERY likely needed with the low Qts woofers you've chosen.
If you are happy with the blend as is, the extra processing only complicates the setup and costs you more interconnects & amplifiers than you need.
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Rudolf:
I put 1.32uF capacitor between the B200 & the ribbon tweeter, crossed it around 17kHz. Yes you got a point there. Maybe i should try to go 3 way.
Tubamark:
Thanks. I was using only 2 channels for the 4pcs woofers earlier, thought of trying this 4channels configuration to see if i can get more power from the woofers. I know it's very redundant & look stupid to XO 4 woofers identically too :|
What do you suggest for me to try out to get better tonal balance?
Eg. which type of slope & what freq to try for the upper & lower pair of woofers?
I must admit that i don't understand those technical stuff like you all here. As i just started & i'm always amazed that you guys know so much :thumb:
Supposed to get the Alpha but supplier was out of stock, therefore got myself the Delta, which later i only find out that Alpha is the better choice for either tube amp & OB, so have to play with what i'd bought.... :duh:
Thanks.
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I have not tried the B200 with 2 15" alphas, although I may in the future.
I think the driver balance is perfect now.
All I can say is Richard has put together an incredible combo.
My version with a highly modded NOS Jolida 102B is still the reference system
for all the new stuff I am building. For me - it is all about tone. And this is rich.
It won't have super bass or super highs. It will draw you into the music.
There was much work done on this system a few years back and I would
highly recommend anyone giving it a try.
Jeff
Hi. I may be able to help you there, as I am part way through building a pair of these...
(http://www.audiocircle.com/image.php?id=22356)
they will be run active via a Rane AC22B crossover. apologies to anyone who has seen me post this on another forum.
Please feel free to add constructive criticism. Thanks, Steve.
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Kind of apples to oranges because I run passive xo. I found that the best way to tame the peakyness of the B200 is to kill it @ around 2k. I don't go heavy on spl's, so I run infinite baffle subs cut off around 70hz,(2nd order), B200 with baffle step compensation to bring down the rising response from as low as they go to 2100 hz and silk dome tweets from 2.1k to as high as they go;(3rd order). I played with this set-up for almost a year tweking the x-over until I was satisfied. I haven't touched it in over a year now. I guess you could say I'm satisfied.
I run the 2 - 15" IB sub drivers, (parrallel), with a 360 Watt plate amp and the B200's + tweets, (also Visaton), with our own 300 Watt Hybrid mono block amps. The system will safely run @ 90 - 95 db in room all day.
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Forgive me if this is a bit OT. I have been reading this thread and I would like to know if I could incorporate the same basic design concept using a Fostex FX120 or Fostex F120A (intead of the Visaton B200) in an open baffle with an Eminence Beta 15 A. I would think a 6 or 6.5mH inductor would work with the Eminence Beta-15A. Any thoughts or ideas on whether this would make a good OB speaker?
Eminence Beta-15A Specifications:
http://www.parts-express.com/pdf/290-410s.pdf (http://www.parts-express.com/pdf/290-410s.pdf)
Fostex FX120 Specifications:
http://www.madisound.com/catalog/PDF/fostexdrivers/fx120.pdf (http://www.madisound.com/catalog/PDF/fostexdrivers/fx120.pdf)
Fostex F120A Speiififcations:
http://www.madisound.com/catalog/PDF/fostexdrivers/f120a.pdf (http://www.madisound.com/catalog/PDF/fostexdrivers/f120a.pdf)
Thanks
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Hi Boys, nice photos,
Do you already see the new Mark Audio 8 inches, ALPAIR 12 full range:
(http://img265.imageshack.us/img265/852/alpair12freq.jpg)
50Wcont, SPL 89,3dB 8ohms, Fo 46Hz, MMD 14,886g MMS 15,871g, CMS 0,750N/M, VAS 22L, Le 0,058mH, QMS 1,454 QES 0,420 QTS 0,327 XMAX 12mm EBP 109 Threshold 0,25W Plenum 10W
Price under 200 US dollars.
Now I wonder what is the best fullrange to use with two ALPHA15A crossing at 300Hz, the new ALPAIR12 or the VISATON B200 ??
Thanks for your advices, Gustavo
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Someone salivating there??
(http://img9.imageshack.us/img9/4889/alpair12details.jpg)
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I think this Fenlon design is very hard to evaluate. It seems to have a very non-offensive frequency response. I would not judge such a unit until I have heard it myself. To be able to say if it is right or less right.
If going with Alpha15 I think one will suffice.
/Erling
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Hi,
could someone please provide the driver placement dimensions for the eminence alpha15a/visaton b200 on a 24"X36" baffle,thank you.
Best regards,elb.
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Hi,
could someone please provide the driver placement dimensions for the eminence alpha15a/visaton b200 on a 24"X36" baffle,thank you.
Best regards,elb.
The 15A needs to be close to the floor and the B200 close to seated ear level or lower if baffle is tilted back a little.
There are a few pictures on page 3 of baffles that size.
Lin
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Hi Lin,
thank you for the reply.I have seen the pictures.
One example has the b200 centred above the alpha 15a and the other has the b200 offset.
Best regards,elb
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About the Alpha 15A frequency response and passive filtering.
I've recently done some justMLS measurements of impedance and response with this driver on a small baffle 60x60 cm. The response is similar to the latest measurement by Scorpion earlier in this thread, but the 2 kHz peak is about +10dB.
The surprise, however, was how the driver responded to passive crossovers. I ran simulations in lspCAD with different filter topologies and component values. It seems like the drivers don't respond well to large series inductors. A larger inductor does very little to reduce high frequency response, and Fc seems to be somewhat fixed around 100-200 Hz. The inductor mostly just reduces overall output and flattens out the 2kHz peak. Some larger values even introduced new peaks in the response. So I landed on 1,2 mH.
When adding a parallel capacitor there is a sharp rolloff at around 500Hz. Then a flat response up to 2 kHz. Increasing the size of the cap does nothing to the cutoff frequency, but only reduces the level above 500Hz relative to the level below. The optimal value here was found to be 220 uF (!).
More complex filters only introduced large peaks in the response.
So crossing these drivers passively may not be as straightforward as one would wish. Using simple crossover theory may produce different results than expected.
Optimal crossover was found to be 1,2 mH in series, 220uF in parallel, Fc=500Hz. Try it out! :wink:
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Dear Community,
My name is Maciek, I'm new at this place but I listen to music for many years. After some experience with other speakers, I decided to start this quite raw and exceptional approach as is OB design. I use now Lampizator Leve 4 DAC, and it inspired me also as the Lukasz uses OB in his reference system.
All what I have now is this and an idea to build a baffle. My question is, if I can get deeper and more bass when the baffle is build ? This is 8ohm Eminence Beta 15A + 4,7mH coil, Sonido SFR175 92dB no filtering and Isophon 10cm tweeter with 2uF Wima capacitor.
(http://www.audiocircle.com/image.php?id=95798)
(http://www.audiocircle.com/image.php?id=95799)
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If your question is - will I get better bass by using a baffle vs playing the driver in free space - then absolutely yes.
If your question is - can I improve on my baffle design as show in the pic - I cannot comment on that, knowing little about your drivers or their specs etc.
I have always approached this as pure experimentation. Use mdf, cut up some test mules, and refine as you go. When you end up where you like, spend the time and energy to build something beautiful, and you're all set!
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Celebrating 10 years!
As I re-set up my B200 and Alpha 15 open baffle, I am reminded of how great this project was from DMason, Richard, Scorpion and others. This and the famous Darkstar thead revitalized open baffle and promoted a number of great drivers and businesses. Now with better electronics - the results are even better. I forgot how wonderfully open baffle fills the room with sound.
Best wishes to DMason and Richard!
Jeff
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Thanks for the reminder. It's too easy to forget worthy advances that have been made and lose our way once again.
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I must say Scorpion was a very kind person and nice to deal :thumb:
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Celebrating 10 years!
As I re-set up my B200 and Alpha 15 open baffle, I am reminded of how great this project was from DMason, Richard, Scorpion and others. This and the famous Darkstar thead revitalized open baffle and promoted a number of great drivers and businesses. Now with better electronics - the results are even better. I forgot how wonderfully open baffle fills the room with sound.
Best wishes to DMason and Richard!
Jeff
I just finished reading that thread, it is one of the best.