Bose 901...really

Rodman99999...When I was at MIT Prof Bose had a huge multidriver speaker hung from the ceiling in the music library. It was mono. (That gives you an idea how long ago it was). At the time his interest was in multiple small drivers instead of one big one. Perhaps he was before his time, because today it's hard to find an audiophile speaker with a 12" or 15" woofer, and 6" woofers are multiplying like cup holders in cars. But his creative idea was to push the resonant frequency UP, instead of down, as all other designers do, so as to operate below resonance where rolloff behavior is smooth and predictable, and therefore correctable by electronic means.

My original 901s were the II version - acoustic suspension with the resonance pushed up to 200 Hz. The equalizer compensated and the boost at 20 HZ was about 40db. They sounded very good and bass was flat to 30 Hz, but I did need to drive it with a HK Citation 16 and the meters showed 200 watts on peak pipe organ music.

The switche to a more 'efficient' vented model was a step backward in my opinion.

Bob P.

But none of those current speaker designs are trying to reproduce everything from 20Hz to 20kHz with that same one driver. The laws of physics just don't allow it without distortion. Perhaps one day the 901 will be produced with a cone than acts as a perfect piston while reproducing all those octaves at the same time. But then- It still won't really matter to me, save perhaps on an academic level. BUT- If they're the wind beneath(and faster air above) your wings: fly with them!! Just don't get too close to the Sun. Some guy named Icarus established that doesn't work very well either.

Rodman99999...But, those little woofers ARE trying to reproduce everything down to 20 Hz, unless you use a filter to electronicly roll off the signal around 40 Hz. They beat their little hearts out trying, without much audible result, but with adverse effect on important higher frequencies. That's why subwoofers have become so popular. They replace what speaker system manufacturers left out.

I don't think I've read any ratings on those smallish woofer systems that claim much below 40-50hz. Nothing in what I consider the bottom octave. And you are absolutely right on two counts: they still beat their hearts out trying, and that's why subs have become so popular. The small woofers in large arrays are a different story. I've not suffered bass-envy since 1981. I built a pair of 8' (1/4 the wavelength of what I wanted),tapered, folded, damped, transmission lines and filled them with the 10" driver that Milo Nestorovic used in his bass system. I needed something that could blend with my Acoustat Model IIIs(had to be fast, and they still work great with my Maggies). The 16hz pedal notes(32ft stop) on the Crystal Clear direct to disk recording of Virgil Fox playing Toccata and Fugue in D minor on the Grand Ruffatti have cracked the ceilings of two of my listening rooms. Expensive, but- Ya gotta love it!