Sorry about posting to this old thread, but I have direct experience with Troels' SBA 761 build. So, this is directly related to the OP.
A very good friend of mine built a pair, with extremely good results. He listens to almost exclusively classical music (20th century and contemporary).
He made all his enclosure panels with DIY constrained layer damping, all crossover components are top quality, extra bracing beyond what the diagram shows.
And the results can easily compete with the quality of speakers that cost several times more $$$. For about $1500 for kits and other parts, I truly believe these sound as good as commercially available speakers that would cost about $8K. And I've heard plenty of very high end gear over the years.
Detail, imaging, soundstage, dynamics, transient response, are all scary good.
I would not hesitate to build a pair of these.
A very good friend of mine built a pair, with extremely good results. He listens to almost exclusively classical music (20th century and contemporary).
He made all his enclosure panels with DIY constrained layer damping, all crossover components are top quality, extra bracing beyond what the diagram shows.
And the results can easily compete with the quality of speakers that cost several times more $$$. For about $1500 for kits and other parts, I truly believe these sound as good as commercially available speakers that would cost about $8K. And I've heard plenty of very high end gear over the years.
Detail, imaging, soundstage, dynamics, transient response, are all scary good.
I would not hesitate to build a pair of these.
Thanks for your valuable comments regarding the SBA 761. I stated this thread to get more information comparing it to the SBA 741 thinking I would build one of those two.
However, several posts here regarding the acoustic issues found in small rooms have caused me to consider other options. I no longer think wide dispersion speakers are right for my situation. Early reflections could significantly diminish the sound quality achieved.
Instead, I'm now considering Open Baffle Dipole speakers. It seems possible to control those reflections with the right combination of speakers and their positioning. This Richard Taylor paper provides a lot of useful information on how to achieve that goal.
http://faculty.tru.ca/rtaylor/publications/reflectgeometry.pdf
I haven't made a decision, yet, but am getting much closer to it. Looking now at both DIY and factory built OB Dipoles.
However, several posts here regarding the acoustic issues found in small rooms have caused me to consider other options. I no longer think wide dispersion speakers are right for my situation. Early reflections could significantly diminish the sound quality achieved.
Instead, I'm now considering Open Baffle Dipole speakers. It seems possible to control those reflections with the right combination of speakers and their positioning. This Richard Taylor paper provides a lot of useful information on how to achieve that goal.
http://faculty.tru.ca/rtaylor/publications/reflectgeometry.pdf
I haven't made a decision, yet, but am getting much closer to it. Looking now at both DIY and factory built OB Dipoles.
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I made a set based on 761 earlier this year and demonstrated it against a clone of the Daudio C-1 open baffle. I find them both comparable in regards to price, looks and performance. For me the OB wins the game with both classical music and jazz music as long as you don't need the highest dynamics because the 761 plays like 12db louder compared to the C-1.
Anyway, the 761 is a good sounding system that needs some attention in the low frequency range, it must fit with the room acoustics and the amplification. I ran it over a Lyngdorf TDAI-2170 with room perfect and that sounded great, although it was somewhat bass-heavy. It had no difficulty to play loud and clean with over 50 listeners in the room.
The open baffle on the other hand sounded better in every aspect but needed a subwoofer to fill the room with sufficiant low end.
In my honest opinion, OB is hard to beat, but ... you need at least 1 meter free space behind the speakers and preferably some DSP or room correction possibilities to compensate for the acoustics.
Anyway, the 761 is a good sounding system that needs some attention in the low frequency range, it must fit with the room acoustics and the amplification. I ran it over a Lyngdorf TDAI-2170 with room perfect and that sounded great, although it was somewhat bass-heavy. It had no difficulty to play loud and clean with over 50 listeners in the room.
The open baffle on the other hand sounded better in every aspect but needed a subwoofer to fill the room with sufficiant low end.
In my honest opinion, OB is hard to beat, but ... you need at least 1 meter free space behind the speakers and preferably some DSP or room correction possibilities to compensate for the acoustics.
If you are going open baffle then you could do a lot worse than build a NAO Note RS II, archived details are available, not sure how you would get hold of the plans for the baffle or the minidsp filter details but I am sure someone will know. However you do need 8 channels of amplification. The website has lots of info so worth a read anyway.
I want to get it to be as good as possible first without any room treatment. And that's based on the approach described in this paper by Richard Taylor:
http://faculty.tru.ca/rtaylor/publications/reflectgeometry.pdf
He discusses how to take advantage of the dipole pattern from an OB speaker to eliminate, or at least greatly reduce, early reflections in a small room.
After that I might add the type of room treatment you suggest, but only as a means for fine tuning once the main reflection issues have been addressed.
http://faculty.tru.ca/rtaylor/publications/reflectgeometry.pdf
He discusses how to take advantage of the dipole pattern from an OB speaker to eliminate, or at least greatly reduce, early reflections in a small room.
After that I might add the type of room treatment you suggest, but only as a means for fine tuning once the main reflection issues have been addressed.
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Sorry, my comment wasn’t meant to encourage you to get the plans or dsp file by the back door and I agree that any info should come from John K if possible. My comment was meant to see if anyone knew if John K was still supplying the data on personal request but obviously unsupported or if someone had taken over distribution of them as I wasn’t sure how it was left.
Hope you find or develop a design that suits your needs, happy hunting.
classicalfan, have you seen these?
Zaph|Audio - SB12.3 3-Way Tower
Zaph|Audio SB12.3 ~ SB Acoustics 12", Dual Midrange, 3-Way
Zaph|Audio - SB12.3 3-Way Tower
Zaph|Audio SB12.3 ~ SB Acoustics 12", Dual Midrange, 3-Way
If there is a way to still legitimately build some of John K's designs I would be interested in it. I'm not aware of one, but please post any information you may find.
As much as I consider myself a DIYer, there is a new planar OB dipole product from Magnepan that looks very interesting and I'm planning to audition it very soon in a local store.
The LRS (Little Ribbon Speaker) is only $650 per pair, and there is a 60 trial return period. Something I certainly want to consider.
Magnepan
Thanks for the suggestion.
I am aware of this model from Madisound, but didn't have it very high on my list mainly due to its size. Also the offset MTM is a little unsettling to look at constantly, although it might produce very good sound.
Anyhow, as you can tell from my recent posts, I'm heading off into a different direction for now. Want to try OB Dipoles and see how well I like them.
Just a suggestion - you may want to start a new thread based on your new design criteria and goals.
Having said that, I came across this recently which could perhaps be useful to you, with the caveat that of course he is trying to sell something but it seems to me that he is also trying to provide (mostly) unbiased info for the diy'er:
Open Baffle Basics
And there are more videos if you find that useful too.
You might also consider a combination of OB planars plus coned drivers similar to what the Philharmonic Audio is doing here.
Having said that, I came across this recently which could perhaps be useful to you, with the caveat that of course he is trying to sell something but it seems to me that he is also trying to provide (mostly) unbiased info for the diy'er:
Open Baffle Basics
And there are more videos if you find that useful too.
You might also consider a combination of OB planars plus coned drivers similar to what the Philharmonic Audio is doing here.
Yeah, I've been thinking about starting a new thread with a lot more information like you suggested. Really only writing brief comments here in response to other messages. Don't want to turn this into a whole new subject.
I've seen the Danny Ritchie video on OB and am considering one of his kits as well.
But my latest intertest, the Magnepan LRS at $650 per pair, is getting fabulous reviews and is really hard to pass up with a 60 day free trial.
I've seen the Danny Ritchie video on OB and am considering one of his kits as well.
But my latest intertest, the Magnepan LRS at $650 per pair, is getting fabulous reviews and is really hard to pass up with a 60 day free trial.
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Such a great post that captures exactly what I have spent so my time reading these threads and not feeling better about any particular design.
Great thread and thanks to all for the responses.
I think that there actually are some excellent DIY kits by a few of the really well known designers. Specifically I would include Dennis Murphy, Paul Carmody, and the late Jeff Bagby in that list. Actually at the top of it. There may be few others worthy of adding, but that's my short list.
Those are the main US entries. In Europe Troels Gravesen probably is the best known, and he offers a wide variety of kits through Jenzen. Also a few of his kits are now available in the US through Madisound.
But as far as all the amateur designers who write posts here and provide details of what they do, I personally would not use any of them. Nor would I be interested in any of the 'house' designs by some of the parts distributers.
It takes a certain skill to be able to tweak a speaker design, particularly the crossovers. Very few people have the experience and talent to do it well, although many try as can readily be seen by all the posts here.
Even newbies think they can do it simply by running one of the several crossover simulators available on line. For a while I was writing posts telling them to just buy a kit designed by someone who really knows what he is doing and forget trying to do it them self. But no one really wanted my advice, and I think some were offended by it. So I stopped wasting my time and don't comment anymore on most of the newbie posts. I just get a chuckle out of some of them for their naïveté and move on.
Those are the main US entries. In Europe Troels Gravesen probably is the best known, and he offers a wide variety of kits through Jenzen. Also a few of his kits are now available in the US through Madisound.
But as far as all the amateur designers who write posts here and provide details of what they do, I personally would not use any of them. Nor would I be interested in any of the 'house' designs by some of the parts distributers.
It takes a certain skill to be able to tweak a speaker design, particularly the crossovers. Very few people have the experience and talent to do it well, although many try as can readily be seen by all the posts here.
Even newbies think they can do it simply by running one of the several crossover simulators available on line. For a while I was writing posts telling them to just buy a kit designed by someone who really knows what he is doing and forget trying to do it them self. But no one really wanted my advice, and I think some were offended by it. So I stopped wasting my time and don't comment anymore on most of the newbie posts. I just get a chuckle out of some of them for their naïveté and move on.
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Well said. The above designers are well respected for a reason. They design good speakers. I love my karios by jeoff bagby even though it has stepped baffle and is sealed. Common sense needs to prevail. Chose a design that is built tested and is avaliable to purchase. Audio companies dont risk there reputation on poor sounding designs.