Problem was the Equalizer added a 15 db bass boost which of course meant they speakers required 2^5 times as much amplifier power to play without clipping. Considering the AR 1500 put out 70-80 watts on a good day, it's not hard to see how the 901s got in trouble reproducing bass all the time.
Realizing the loudspeaker's thirst, and in order to accommodate it, in the mid '70s Bose sold a high powered amplifier, the 1801. I think they made a matching preamp, too, with built in EQ for the speakers.
Fun fact: at the '77 summer CES, MLAS was showing off their HQD system, requiring among other things, six ML-2 class A amps. Mark didn't yet have that many made, so he drove the two Hartley 18 inch bass commodes with an 1801. My guess is that the Bose probably did a better job at it, than his own amp--unless his idea was to bridge two of his amps for the bass cabinets, in which case you would need eight ML-2s, four per side. That certainly could have been a possibility, given Levinson's 'money is no object as long as I'm the one receiving it' philosophy.
I ended up suspending them from the ceiling also
Bose 901 was never inexpensive (although some said the drivers were cheap); with that in mind, and in order to maximize
profits sonic quality, plus in order to satisfy the requirements of really big spenders, Bose advertised a 'super system' that included four 901s--two on their dedicated '60s-modern space-age stands, with two hanging down from the ceiling. This, in order to accentuate their special 'wall of sound' sonic presentation. I would have like to have heard that set up, and even without hearing it I'm certain that Phil, Ronnie, and the Wrecking Crew's 'Be My Baby' (in mono) sounded just fine over that system, turned all the way up, of course. I am serious.
The Absolute Sound was founded after
Harry Pearson was unhappy with the sound quality of the Bose 901's he purchased.
Julian Hirsch, an objectivist audiophile, emphasized measured performance of audio gear from the earliest days of this hobby, and
loved the Bose 901
Hirsch took a lot of heat for his 901 review (as he did with his L100 write up), leading many to suspect advertising shenanigans. It wasn't just Julian, however--the press in general were enthusiastic-- Hans Fantel writing for the NYT comes to mind. For their part
, Consumer Reports complained how they couldn't really get into six foot long violins (or whatever it was) due to the loudspeakers unusual sonic presentation. Bose took them to court over it, arguing libel, which was a pretty stupid thing to do-- at least back in the '70s, a time when there was more concern over press freedom for diverse opinion.
Gordon Holt was equivocal to a degree, writing:
Thus, some 901 installations will have deep, tight, and quite well-defined bass, while others (in the majority) will exhibit uncontrolled bass resonances at frequencies which are entirely a function of the room dimensions. This no doubt explains the very widely conflicting reactions of different listeners who auditioned the Bose 901 in stores or purchased them for use at home. It is ideal for rock enthusiasts to whom sheer sonic impact is of paramount importance, and for classical listeners who want the next best thing to ambient stereo without the cost and the bother of rear-channel add-ons. However, we doubt that the 901 will appeal to perfectionists who have developed a taste for subtleties of detail and timbre.
As far as Pearson? His idea of sonic excellence was a set of Infinity IRS in a rather smallish room--some said it was really a closet, leading many to speculate that it was more like listening to headphones.
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As popular as the 901 was, I never heard it in an 'ideal' listening situation, which many rooms, because of decorating schemes, couldn't supply. I knew folks who owned them, but they were always placed up against a back wall, in a corner, or such. One guy turned the multiple drivers forward, because that was what he liked best.
I remember hearing 501s in a couple of living rooms. Those were advertised as an 'easier to accommodate' 901--certainly less expensive. My own 'living with with Bose' experience was a short lived set of 'Interaudio by Bose' box speakers (standard air suspension woofer plus two free standing angled tweeters, as I recall); you could say they were average sounding, for the time. I don't even remember where I got them, or what I did with them. Probably from a trade. Plus a pair of 301s I owned for a few weeks, and that I couldn't really figure out how to work.
That said, one of the best auditorium sound systems I remember featured two 'pro' Bose loudspeakers, that looked like 901s, but with the angled multiple drivers (if that is what they incorporated) turned toward the audience. I have no idea if they used 'active' EQ. But for a high school gym, they pretty much did the trick. If I lived in a HS gym, those would be on my A-List, for sure.