Most sensitive/efficient subwoofers in the world?

Ojas Audio comes to mind with their ultra-sensitive huge subs as one pioneering company when it comes to extracting most clean SPL with lowest watts from an actual heavy subwoofer. And it really is heavy.
Was it something like a 30" Fostex special sub driver?
Very revered in Japanese high-end listening rooms and I totally understand why a subwoofer should be as sensitive as possible. Why waste power as heat?
There is talk of a special kind of nuance-rich presentation with ultimately sensitive subwoofers, one where it’s a trivial matter to distinguish a double-bass from a synth, let’s say. Authenticity as such would naturally arise from the highest sensitivity, lowest excursion subwoofer. This is for all speakers of course - remember “dynamic compression”?

I do think that pro-style woofers in larger cabinets can have some benefits regarding distortion. Typically the motor structures are pushed well into saturation, modulation distortion can be lower, and the low Q requires less equalization down super deep (versus a higher Q design).

That being said, most people don’t want refrigerator sized boxes in their home and would gladly trade some box size for sensitivity and use a larger amplifier. With modern woofer designs, the results can still be very good. Distortion is also less audible at lower frequencies and the improved in-room response of multiple distributed woofers is often a better approach to lone large unit.

While those 30" woofers were designed for church pipe organ use, there are much better options now (that might not look as cool) using multiple 18-21" drivers.

The ojas audio guy is an artist first and foremost and there are a bunch of technical issues with what he’s doing (though obviously the reused altec/JBL/tannoy and other designs are good for what they are).

Oh yeah! That’s the guy that Steve Guttenberg interviewed a few times a while back.

Chris, this takes me back to my original thoughts when we purchased our house almost two years ago now… That being the thoughts of having infinite baffles subwoofers in the ceiling/attic.

What’s your thoughts on that approach? One definite benefit… Zero floor space used.

So adding gain with just maximal baffle area, but with no pressure chamber?

Infinite baffle subwoofers can work extremely well. My dad’s company did some IB 12" drivers when I was a kid and there also used to be web forum called the “cult of the infinitely baffled” lead by a guy named ThomasW who was using some drivers from my former employer (in my early 20’s) Adire Audio in a big IB.

My first recommendation would be to put a freestanding subwoofer in the exact location where you plan to do the IB and do some basic acoustic measurements to see if you can get an acceptable response before cutting a hole in your floor/ceiling.

Secondly, I stongly recommnd horizontally opposing the drivers (possibly in a push/pull arrangement) to greatly reduce the structural vibration in the home.

You will need more/larger woofers and less pwoer than you think, as the system is very efficient in the deep bass. something like 2 x 15" is probably a minimum size.

Keep the manifold (coupling chamber for the woofers) as shallow as possible and the opening to the room as large as possible to avoid duct resonances (which can cause huge peaks in the response as a mis-tuned 4th order bandpass front chamber). Using a large air return cover or similar is a good idea, not something sall like a 4x10" heater opening.

Some of the subs from parts express, FI Car Audio, and Acosutic Elegance are good options. Look for a Qts around .5-.7 and a low resonance in the 20-30 Hz range and larger Xmax (15+ mm). Also, you want the to be surround limited, so as not to bottom out with loud bass passages.


Nelson Pass’ DIY subwoofer project. Not all that practical, but a fun read. The guy does have fun at what he does . . .

“Funny things happen when your speakers are flat to 13 Hz. You have to be careful about your tone arm, your windows, your neighbors, and your bowels. After we got the system running, we spent a hour or so going around the room bolting down or otherwise re-arranging knick-knacks, shelving, furniture and windows that began rattling. After that, we called up our friends and had a little party.”