Official O.B. Gallery.....bought or built, anything goes.

Open Baffle speakers seem to be gaining in popularity among enthusiasts and with the DIY types. I've seen OB gallery's elsewhere which were a great inspiration during my build, and thought it was time we had a gallery of OB speakers ourselves.

For this thread please include a picture or pictures of O.B. speakers that you've built, bought, or just think are an interesting design.

I'll start with a pair or OBLA-33 OB line array's I recently built. While the tweeters are monopole, the mid-woofers are OB all the way.



[URL=http://s1223.photobucket.com/user/Rob41/media/DSCN1280.jpg.html][/URL]

[URL=http://s1223.photobucket.com/user/Rob41/media/DSCN1293.jpg.html][/URL]

Rob41 said:

Open Baffle speakers seem to be gaining in popularity among enthusiasts and with the DIY types. I've seen OB gallery's elsewhere which were a great inspiration during my build, and thought it was time we had a gallery of OB speakers ourselves.

For this thread please include a picture or pictures of O.B. speakers that you've built, bought, or just think are an interesting design.

I'll start with a pair or OBLA-33 OB line array's I recently built. While the tweeters are monopole, the mid-woofers are OB all the way.



[URL=http://s1223.photobucket.com/user/Rob41/media/DSCN1280.jpg.html][/URL]

[URL=http://s1223.photobucket.com/user/Rob41/media/DSCN1293.jpg.html][/URL]

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I'm using, what looks like, an RT-707, so are those (roughly) 7" drivers? Maybe 6.5"?

Very nice. Must sound pretty impressive. Isn't spacing a challenge? Can't recall the "rule of thumb" with driver spacing. I know that's not the case with the tweeters, thankfully.

Op, lots of work there, but turned out great. I hope to build one some day. 2 drivers per side.

Thanks. Mine were a lot of extra work because they are also MTM, line arrays. However, a whole lot of OB designs are far more straight forward.

[URL=http://s1223.photobucket.com/user/Rob41/media/OB_FE_108E.jpg.html][/URL]

[URL=http://s1223.photobucket.com/user/Rob41/media/ab3dbbf63bd8db70ced1cc16781a25c1.jpg.html][/URL]

As you know, I've admired those from your first post about them. What is their frequency response, BTW? How is their bass? Sensitivity?

Zonker92 said:

As you know, I've admired those from your first post about them. What is their frequency response, BTW? How is their bass? Sensitivity?

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Thank you and good question. I should probably already know the sensitivity. I'll do that after dinner. The effective frequency response without my bass augmentation is 65-19kHz. I have them crossed at 65Hz and they roll off steeply at 19kHz. With the bass augmentation, the system is good to about 24Hz.

Here are some old pictures of my open baffles and no-baffles rigs. OBs are based on the Martin J. King Project #9
http://www.quarter-wave.com/Project09/Project09.html

The FR drivers are Visaton B200s: LF duty is handled by Eminence Alpha 15As. However, those FR drivers have now migrated to my no-baffles rig (inspired by a poultrygeist posting of a no baffle rig he built). OBs now have Audio Nirvana Super 8s. Both are biamped; SS for the LF and single-ended tubes for the HF.

OB rig has a miniDSP electronic crossover; no-baffles a rane analog x-over (though I now have another miniDSP, which will move into that slot).

no baffle pictures here:
http://www.audiokarma.org/forums/showthread.php?t=566879&page=54

rogerfederer said:

Here are some old pictures of my open baffles and no-baffles rigs. OBs are based on the Martin J. King Project #9
http://www.quarter-wave.com/Project09/Project09.html

The FR drivers are Visaton B200s: LF duty is handled by Eminence Alpha 15As. However, those FR drivers have now migrated to my no-baffles rig (inspired by a poultrygeist posting of a no baffle rig he built). OBs now have Audio Nirvana Super 8s. Both are biamped; SS for the LF and single-ended tubes for the HF.

OB rig has a miniDSP electronic crossover; no-baffles a rane analog x-over (though I now have another miniDSP, which will move into that slot).

Click to expand...

Very nice. I like how you made the connections and hid the wires. Very clean build!

Poultrygeist is a big part of the reason I went the OB route. :thmbsp:

Those are true statement pieces, Rob. Definitely something to be proud of. I'm still amazed at your build speed...there must be Adirol or something behind it. It's just not normal. :scratch2: .

Here's my humble first and only OB build. This was Poultrygeist's recipe and he was so enthusiastic about it and it seemed sufficiently cheap and easy enough that I couldn't resist giving it a try. And I'm glad I did because I learned A LOT from the experience. Being my first speaker build and first time to use an active crossover, I learned a good deal about frequency range assignment and driver integration/interaction. Orders of magnitude more than buying and selling speakers off of CL ever taught me, and the fact that the damn things actually sounded pretty good was just icing on the cake. The H-frame sub with the Alpha 15a's was the big surprise. No, you can't get 'em real loud but certainly loud enough to be respectable and their musicality was like nothing I'd ever heard from a dedicated subwoofer or LF driver in a monopole monkey coffin. The BG Neo3 turned out to be one of the sweetest tweeters I'd ever heard (in the pic you can also see the Selenium horn loaded tweeters I first used and had in place at the time of the pic only for comparison against the Neo3's). The Beta mid was the weak link, but I didn't know how to tame its response at the time so it came across as a little "shouty". Nevertheless, they were a very fun listen and did some types of music alarmingly well, but compared to the Magnepan MG-IIIa's and Infinity QLS-1's I was listening to at the time just couldn't keep my interest. Soon I'll be starting on my next attempt at OB which will borrow a few elements from these rascals.

Rob41 said:

The effective frequency response without my bass augmentation is 65-19kHz. I have them crossed at 65Hz and they roll off steeply at 19kHz. With the bass augmentation, the system is good to about 24Hz.

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Cool; thanks!

My humble contribution. Drivers are University 6201 driven by CazTech SE-845 mono-blocks.

My next OB project is on the drawing board and will feature two Alpha Eminence 15a woofers and one Tang Band W8-1808 per side bi-amped via a Dahlquist DQ-LP1 driving a Crown X1000 on the 15's and either the Quicksilver 300B SETs or CazTechs on the Tang Bands.

TubeHiFiNut said:

My humble contribution. Drivers are University 6201 driven by CazTech SE-845 mono-blocks.

My next OB project is on the drawing board and will feature two Alpha Eminence 15a woofers and one Tang Band W8-1808 per side bi-amped via a Dahlquist DQ-LP1 driving a Crown X1000 on the 15's and either the Quicksilver 300B SETs or CazTechs on the Tang Bands.

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Very cool set up there and with tube amp to boot! And I love your design. It goes to show just how simple it can be to build and I'm willing to guess they sound great. Thanks for sharing.


@Yes, they are 6 1/2" drivers but are crossed below the 2208Hz point where combing would be noticeable. Even when they were crossed a bit higher at 2400Hz I could not detect any combing.

Rob41 said:

Very cool set up there and with tube amp to boot! And I love your design. It goes to show just how simple it can be to build and I'm willing to guess they sound great. Thanks for sharing.


<snip>

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Thank you, Rob.

Poultrygeist guided me to the JE Labs and Martin King sites. My first attempt is based on the JE Labs design.

Still trying to decide whether to go withe two H-Frames per side for the 15's on my next project or keep it simple and use a simple baffle with the 15's arranged vertically.

tomlinmgt said:

Those are true statement pieces, Rob. Definitely something to be proud of. I'm still amazed at your build speed...there must be Adirol or something behind it. It's just not normal. :scratch2: .

Here's my humble first and only OB build. This was Poultrygeist's recipe and he was so enthusiastic about it and it seemed sufficiently cheap and easy enough that I couldn't resist giving it a try. And I'm glad I did because I learned A LOT from the experience. Being my first speaker build and first time to use an active crossover, I learned a good deal about frequency range assignment and driver integration/interaction. Orders of magnitude more than buying and selling speakers off of CL ever taught me, and the fact that the damn things actually sounded pretty good was just icing on the cake. The H-frame sub with the Alpha 15a's was the big surprise. No, you can't get 'em real loud but certainly loud enough to be respectable and their musicality was like nothing I'd ever heard from a dedicated subwoofer or LF driver in a monopole monkey coffin. The BG Neo3 turned out to be one of the sweetest tweeters I'd ever heard (in the pic you can also see the Selenium horn loaded tweeters I first used and had in place at the time of the pic only for comparison against the Neo3's). The Beta mid was the weak link, but I didn't know how to tame its response at the time so it came across as a little "shouty". Nevertheless, they were a very fun listen and did some types of music alarmingly well, but compared to the Magnepan MG-IIIa's and Infinity QLS-1's I was listening to at the time just couldn't keep my interest. Soon I'll be starting on my next attempt at OB which will borrow a few elements from these rascals.

Click to expand...

I can see you put a lot of thought into them Michael. Nice work. You've got the beta off center as is accepted as appropriate. It's too bad you weren't able to integrate it better.

In spite of them falling a bit short compared to your other speakers (not hard to do btw) isn't it amazing how good they sound? I think it's a lot harder to get OB's wrong than speakers with enclosures.

I can see the MA-5002 in the picture but can't make out the black amp. Is that a Threshold?



@TubeHiFiNut, I'm willing to bet your speakers sound better than a lot of respectable speakers people seek to buy. Do you feel like you went down the rabbit hole?

Rob41 said:

<snip>

@TubeHiFiNut, I'm willing to bet your speakers sound better than a lot of respectable speakers people seek to buy. Do you feel like you went down the rabbit hole?

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In my opinion, this is a rabbit hole that I intend to follow to Wonderland. These simple speakers, based on what are really some fairly nondescript University 12" coax drivers, sound far better that I ever expected them to sound.

There is something about the overall balance and fidelity that is quite addicting. The bass is tuneful and articulate with lots of air around the instruments.

I should have the drivers for my next build soon and am getting on the woodworkers schedule (I have 10 thumbs when it comes to working with wood).

One more thing that I think bears discussion: These speakers are just flat out FUN! They beg you to listen to more music - Jazz, rock, folk. Toe tapping is not an option, it is a requirement!

Folks have to make their own decision but I am sure glad I took the plunge.

TubeHiFiNut said:

In my opinion, this is a rabbit hole that I intend to follow to Wonderland. These simple speakers, based on what are really some fairly nondescript University 12" coax drivers, sound far better that I ever expected them to sound.

There is something about the overall balance and fidelity that is quite addicting. The bass is tuneful and articulate with lots of air around the instruments.

I should have the drivers for my next build soon and am getting on the woodworkers schedule (I have 10 thumbs when it comes to working with wood).

One more thing that I think bears discussion: These speakers are just flat out FUN! They beg you to listen to more music - Jazz, rock, folk. Toe tapping is not an option, it is a requirement!

Folks have to make their own decision but I am sure glad I took the plunge.

Click to expand...

Yeah, I kept seeing Poultrygeist talk about OB's that I looked into it some more and I started seeing a consistent picture emerge. Everyone who's gone down the OB rabbit hole describes OB's as have a very natural and "more right" kind of sound. The resonances an enclosure has regardless of damping or bracing is a big variable that does color the music.

The fact that someone new to this can achieve amazing results is a testament to the inherent ease of the design.

Keep us posted on your upcoming build, I'd be very interested to follow along. :thmbsp:

I will do so. Pictures will be posted as things progress.

And I am interested in hearing your continued impressions of your labors of love. Truly a statement pair of speakers!

Rob41 said:

I can see you put a lot of thought into them Michael. Nice work. You've got the beta off center as is accepted as appropriate. It's too bad you weren't able to integrate it better.

In spite of them falling a bit short compared to your other speakers (not hard to do btw) isn't it amazing how good they sound? I think it's a lot harder to get OB's wrong than speakers with enclosures.

I can see the MA-5002 in the picture but can't make out the black amp. Is that a Threshold?

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No, that was shortly before the serious amps (Aragon, Threshold, TAD-60, F5) showed up. The black amp on the floor is a hot-rodded Hafler 500 and on the rack is an ST-70. Also on the rack is my first tube preamp (AMC) and the acquisition of that piece marked the point where some serious and rapid growth in the hobby began. I think that's probably why I never tweaked on the OB's and instead just put them on the shelf...once the really good electronics started showing up all my best speakers were taken up a notch (or two) and I was stoned on the sweetness, with no measure of confidence whatsoever that the OB's could keep up with the "big dogs". Man, looking back I sure didn't know it at the time, but I was fixing to have two solid years of consistent and frequent "holy shit" moments. Now the bar is set and I have a target to shoot for with my next OB build.

Chills up your spine, a grin ear to ear, and maybe a few tears? Aren't those "holy shit" moments great? My speakers and DSP have done that for me. I think we have both been fortunate to have such huge leaps forward in a hobby where so many gains are usually subtle.

I can't wait to see how your OB build progresses. You know how to do your homework so I already know they will sound great. Hopefully they will eclipse your Maggies and Infinity's.

I reread your earlier post and something I missed the first time around was when you mentioned "musicality" when you referenced your OB's. I think that is a very telling description of one of the traits inherent in an OB design. It can be very difficult to achieve in an enclosed design but seems to come naturally to OB speakers.