open baffle sound

[rudy sesztak]

Has anybody done any experimenting with OB systems? Like what size board to use, size of wings etc. I put my JBL D123's with 077's on temporary boards, and the sound was GREAT!,open,airy,transparent,with no boxy, muddy sound. I'll never go back to other kinds of systems again. The bass is weaker, but you can always ad a sub-woofer.-RUDY

[badman]

Has anybody done any experimenting with OB systems? Like what size board to use, size of wings etc. I put my JBL D123's with 077's on temporary boards, and the sound was GREAT!,open,airy,transparent,with no boxy, muddy sound. I'll never go back to other kinds of systems again. The bass is weaker, but you can always ad a sub-woofer.-RUDY

OB systems have been discussed extensively, but not so much here, as this site tends to have people more interested in creating (or cloning or restoring) classic JBL/Altec "Box" style loudspeakers. www.diyaudio.com (http://www.diyaudio.com) has extensive writings on OB, if you want to learn about it the http://www.diyaudio.com/forums/multi-way/142015-my-open-baffle-dipole-beyma-tpl-150-a.html thread here is about as good a start as any. There's plenty of writings on OB by others there as well as at www.linkwitzlab.com (http://www.linkwitzlab.com) and www.musicanddesign.com (http://www.musicanddesign.com)

OB is a box type so just like there's no 1 way to design a vented or horn system, there are different breeds of OBs. Best performance seems to be achieved with no baffle at all, just free-air drivers, but this method requires a lot of EQ and crossover effort, and more drivers to create a given SPL than systems with more baffle.

[4313B]

The 123's should be pretty good candidates for OB designs. There aren't too many JBL transducers that I can think of that are. Greg and I briefly discussed this a few years ago.

The Synthesis 8 driver looks like a good candidate but it is unobtainable due to Harman's war on counterfeiting. Other candidates might be the LE8, LE10 and maybe some of the GTi drivers.

[badman]

The 123's should be pretty good candidates for OB designs. There aren't too many JBL transducers that I can think of that are. Greg and I briefly discussed this a few years ago.

The Synthesis 8 driver looks like a good candidate but it is unobtainable due to Harman's war on counterfeiting. Other candidates might be the LE8, LE10 and maybe some of the GTi drivers.


The 123A sounds terrific on open baffle, and as it possesses a smooth, extended top end with low inductance (for a 12"), filter design is fairly simple. LE8T performs well on OB but as a dedicated mid, if it's trying to do 100Hz and down, the mids and highs get muddy.

http://www.enjoythemusic.com/diy/0310/diy_open_baffle.htm

Above is a writeup of the 123A OB.