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Rob's OBLA-33 (Open Baffle Line Array) project.

Hans did a wonderful job. Those are awesome. Plus, I love the looks of the ripole subs. I've never heard them, but I'm very curious about them, as I've been studying OB designs lately. I'd love to combine a OB sub design, with a line array, for the upper end. I think that'd be the best of both worlds. Add a Class A and/or a SE tube amp, and a nice tube preamp, and I might finally feel like I'd have a finished system, for a while! (Maybe)!!!

Thanks for sharing!
 
my goose bumps turned into pimples....now I got to go pop them!
The video sounded really nice!
DC
 
One thing Hans mentioned that I too have found, is that due to the difference of resistance between the mids and the tweeters, it would be very challenging to design a passive crossover that would work. We are both actively crossing these so it's not an issue. I realized after viewing many of his videos that I never did a video of mine so I'm uploading a video right now to u-tube but have another couple hours before it will be ready.
 
Okay, thanks to Hans for making me realize I hadn't yet done a video of my OBLA-33.

 
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Hello Rob and all builders following this thread. This is Hans in Sweden who has had the pleasure of following this fantastic thread since Rob started it about a year ago. Thank you so much Rob for sharing your awesome design and for the kind words of my build. Your theory discussion and build photos in this thread has been a true inspiration to me, so I spent some nice months outside in the yard this fall building my speakers, very much based on your design. I have done some other speaker builds the last 5 or so years, mostly open baffle, using coaxials and widerange drivers, but this design and build is in another league I think. I think this is the first build I have done that can be called 'fullrange'. It is my very first acquaintance with line array designs, and I am (openly :o)) baffled at the sound stage, dynamics and very large sweet spot of Rob's design. I call my speakers Holmsound Ljumviken, after my hometown Holmsund and the nearby beach Ljumviken, where my kids and I have spent many days of fun in the summers. I would totally recommend others to build Rob's design and once again and I thank you Rob for sharing the design and for starting this fantastic thread.
 
Welcome to AK, Hans! Beautiful work.

Well this is icing on the cake. As if you needed any more evidence that you built a great pair of speakers...now they're building them halfway around the world. :cool:
 
Thanks for your very kind words Hans. I'm so glad you found inspiration in my design. But I gotta tell you, I've found inspiration in your body of work building speakers. I'm loving your ripole subs and the other projects I've seen in your videos. I'm very impressed with your work and I'll be lucky to achieve so many really cool projects.

@toxcrusadr, absolutely is icing on the cake. I couldn't be happier that such a nice guy like Hans has taken on this project and made it his own with his vision as well. Hans is a far more experienced builder than myself so for him to be impressed speaks volumes.
 
Thanks again Rob for your very kind and positive comments about my build! And MANY thanks for 'showing me in the right direction' with your, in my opinion, groundbreaking design and build of your OBLA33s. I am in doubt a bit if the wings I added was a wise thing or not, since you told me that you have very good output down to 60 Hz in your slender and elegant baffles. I literally hear things in these speakers that I haven't heard before. Like this morning, when I was listening to a song, where I have always liked the 'fat' snare drum. With the line arrays, I heard this morning that behind the snare drum there is a fast and faint 'chickety-chickety-chickety' sound from maraccas. I hadn't noticed that before on this track, and I'm very familiar with it. I guess I would have heard this faint maraccas sound in head phones, but I haven't noticed it when played on my other speakers. So the line arrays are very revealing of details in the recordings. About the ripoles; well, they work very well I think. Without any eq or compensation circuits (like the german guy Ridtahler, the ripole 'inventor?', states is necessary). I let the ripoles work up to 80 Hz and I can hear good output down to the mid 20s. The bass drivers I use are the cheapest available 15 inches here in Sweden (around $40/driver), and I was lucky that the parameters are well suited for ripoles. The drivers have fs of 34 Hz and qts around 0.65. Which are values that Ridtahler recommends for ripole builds. Well, I'm a very happy camper now, I'm very pleased with the sound. Once again, thanks Rob, for sharing your great design with me!
 
I too have noticed things in recordings I've never heard before. Line arrays when done correctly have an almost eerie ability to to bring out content that is not revealed my most speakers. The caveat to this is that weaknesses in the rest of the chain can reveal themselves as well.

I appreciate your insight into the Ripole's. I have several months before I start but it's down to either a Ripole design such as yours or a PPSL. Both designs are good at reducing distortion and upper harmonic distortion. This often leads some listeners to believe the output is somehow less than a conventional design but it's more a matter of reduced distortion and reduction of unwanted harmonics.

I'm going to shoot for 18Hz-about 75Hz even if it means overall output is reduced to achieve that range. With enough of the subs in place I'm sure spl's will be loud enough.
 
Hey Rob,

I'm not sure if I've mentioned this or not, but you really need to check out the GR Research Rythmik servo-subs. Danny Richie offers 4 different servo subs, and two different servo plate amps. They're supposed to be excellent sounding subs. But, the best thing, they're designed to be used OB! OB servo controlled subs, that extend to 20 Hz, with slam.

Here's the subs:

http://gr-research.com/sw-12-08-1.aspx
http://gr-research.com/sw-12-04.aspx
http://gr-research.com/sw-12-08fr.aspx
http://gr-research.com/sw-12-16fr.aspx

And the plate amps:

http://gr-research.com/electronics.aspx

Lot's of discussion info, at the GR Research Forum on Audio Circle:

http://www.audiocircle.com/index.php?board=16.0

There's even an AC member, that builds these knock-down kits for the subs:

image.php
 
I have read the Nelson page and the DIY page several times before and I'm sure I will again.

Thanks for the info on the servo subs. If you did post about them before I apologize as I don't remember seeing it before. Those servo controlled subs look great and the discussion link has a lot of information. I like that they work OB as well. It would be easy enough to experiment and see what works best for me. The prices seem reasonable as well.

Thanks for the links Stimpy!
 
Rob41 said:
Those servo controlled subs look great and the discussion link has a lot of information. I like that they work OB as well. It would be easy enough to experiment and see what works best for me.!
Click to expand...

This thread has a good look at several of the available premade knock-down H-Frame kits. A DIY type could probably build their own, following the pictures shown in here:

http://www.audiocircle.com/index.php?topic=130747.0

Singles, dual's, three and multiple sub versions available. You can even build up to this: :rockon:

655ac98c-fc75-4140-92e0-2a970021ddff_zps35qowwut.jpg
 
I really like the idea of servo controlled amps but so far I couldn't find what I want to know. In order for the sub to have it's servo function, is it necessary to use one of their plate amps or could I use one of my existing amps?
 
Rob41 said:
I really like the idea of servo controlled amps but so far I couldn't find what I want to know.
In order for the sub to have it's servo function, is it necessary to use one of their plate amps or could I use one of my existing amps?
Click to expand...
Yes, for the servo function to operate, you have to use the servo woofers, with the servo plate amps. But, I 'believe' one plate amp can power up to three servo woofers. So, the triple woofer stack, that I pictured, would only require one amp.
 
Thank you, Rob, for posting all the pictures and detailed information regarding your speakers build! I also got the inspiration from you to build my own open baffle speakers. This was my first attempt to build speakers and the results are beyond my highest expectations. The pictures in my theater room are the best I can do with all the black velvet absorbing light from the camera flash. They are 75 inches tall. No fancy wood work, since they will be covered with black grill cloth. Each speaker has a center column of 9 PT2C-8 tweeters and two columns of the 6 1/2 inch woofers, total of 18 woofers in each speaker. I am using an Ashly XR-1001 electronic crossover. The crossover frequency I have settled on is just slightly higher than 2000 K , with a Linkowitz-Riley steep 24 dB per octave filter. The woofers are crossed over to SVS powered subs at 80 Hz. The speakers sound just fantastic with no lobbing or any other objectionable issues.

Some background. I am a recently retired psychotherapist and needed a winter project to get into. I have had many interests throughout the years, pilot, traveling etc., but always came back to and enjoyed an interest and passion for electronics, audio and recently home theater. I collected a large amount of McIntosh stereo equipment over the years and owned countless great speakers. Some of the speakers were the Infinity Kappa 9, McIntosh, Ohm Walsh, VMPS, GoldenEar, Carver Amazing Platinum Mark IV, etc.

I am considering having custom made passive crossovers, 4th order Linkwitz-Riley, 2100 Hertz. I would like to be able to eliminate the electronic crossover, and all the additional in-wall wiring that I will have to do with bi-amping the speakers in the theater room. I am thinking the passive crossovers may degrade the sound of the speakers. Comments would be appreciated.

These speakers that I have constructed have impressed both me and my wife. They are absolutely incredible! Thank you again Rob.

100_5620.JPG 100_5622.JPG 100_5642.JPG 20160123_083943.jpg 20160123_110654.jpg 20160123_111729.jpg
 
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Man this thread is audio porn! What a brilliant read with additions keeping it as fresh as when it started. Rare to me that a thread isn't living off the initial content and just keeps piling on goodness.

Much to be proud of here Rob.

Hans you might need a BIGGER TV now? ;)
 
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