Open Baffle

[garto]

Hey Everyone,
This is my first post but I've been visiting a lot of forums recently to try and figure this out. I have seen speakers that are basically open baffles in that there is front and back sheet, but no side sheets enclosing it. I can't seem to find a picture now but its little more than just flush mounting subs into a piece of wood and shaping that wood. No box, no enclosure. I was wondering how they do this, what the quality is, and what speakers they use (if theres a special type for this application).
-Chris

P.S. I don't think its an infinite baffle because those speakers are enclosed on the front side to isolate the two rooms, these are not, they are just free standing towers (3 ways to be exact).

 

[jaxvon]

Might you be thinking of the Linkwitz Orions?

The bass reproduced from such speakers does sound excellent, but you should note that it requires some hefty EQ to avoid issues created by the open baffle configuration.

 

[garto]

So the real only downside is the extra price due to the need of an EQ. I'm guessing there needs to be more amplification as well, but is that it? Could I just go out and slap a sub onto a board, grab and EQ and a big amp and go to town? or should I just stick with a more conventional sub like a sealed or ported.
-Chris

 

[Dusty Chalk]

I recently read a review of the Jamo open-baffle design. The review said that the main problem with the design is that air pushed from the front just goes around the baffle to the back (nature abhors a vacuum and all that), rather than eminating as sound. The solution that Jamo puts forth is to put two very large bass drivers on the thing to compensate. I.E. not just EQ, but you need the capability of playing that extra bass. So basically, if you were to put this driver set in a "normal" speaker box, it would be extremely bass-heavy, but because it's open-baffle, it counters the bass-suck effect.

The Wilson Benesch Bishop is another example, I believe.

 

[Rip Van Woofer]

The woofer drivers for a dynamic (i.e., cone, not planar/electrostatic) open baffle speaker need to have very large excursion capabilities, to handle the required EQ and to push the quantities of air needed for decent bass.

The baffle dimensions are quite critical too. And they need to be well away from the wall behind them - about 3 or 4 feet.

I think the old Carver Amazing speakers managed the trick without the EQ, however. It involved specifically designed woofer drivers of high excursion and a very specific Qts to mate with a carefully designed baffle if I recall.

When done correctly the quality of bass is very natural and tight. "Room boom" is reduced. I own a pair of open baffle Orions and love them.

If DIY is your thing and you have some time, curiosity, and about $400 to spare, you could build the small Linkwitz "prototype" PMT1 design (8" two way with optional passive EQ) to check out the concept. I did so before building the Orions and they're terrific speakers in their own right. They work well in a small room like a bedroom or den, or as surrounds.

Linkwitz's PMT1 design: http://www.linkwitzlab.com/proto.htm#PMT1

My PMT1 project gallery: http://www.bruce.coppola.name/audio/LinkwitzMiniDipolePrototyp/index.html

Elsewhere on Linkwitz's site you can read about the theory of open-baffle speakers in eye-glazing detail!

 

[Biscokid]

you may want to also check out this thread from audiocircle

http://www.audiocircle.com/circles/viewtopic.php?p=250855#250855

It mainly talks about OB use of the Viston B200 full range driver.