901 series 2 speakers

back in the 70's, i read that you should have at least 100 watts per chanell for these speakers.

Hey johnny, thanks for the history lesson. *L*  That was certainly my 'state of the art' for the era, and to get a 'flashback insight' on WTF was going on makes too much sense. *G*

The 901's were still impressive for the 'time and place', and I was happy as a well-fed pig in mud back then.  They could almost literally blow my friends away, even given the limits they were in.

As for the stated demo, it seems to relate to the modern 'line source' stack we see in concerts, driven by enough wattage to pound nails into softwoods. *L*  Small wonder the first 5 rows go home with their ears ringing. ;)  Perhaps, fortunately, I couldn't afford those seats on a regular basis....I wouldn't be able to hear what I can...*L*

Bose was right at the time....massed small drivers can work wonders, given a certain level of 'control' with active EQ.  And it still works...I'm a fanboy of active EQ to this day, dialing for 'flat response' in the space I'm faced with.  "All things being equal", if you will. ;)

Thanks again....*G*

You are not completely wrong, schubert. When hung from the ceiling and close to the ceiling, bars always had the eight drivers pointed to the front. 8>)

I wouldn’t take that as any definitive answer. It’s not like bar owners are known as acoustic geniuses or even for reading the instructions.

I was a sales guy at a Bose dealer in 1975-6 and I read up on all Bose's literature about the 901s' theory of ops and placement.

The Bose 901 was the result of Amar Bose’s Masters thesis at MIT, where he measured and studied the ratio of direct vs. reflected sound in Boston’s Symphony Hall, which itself is modeled after the second Gewandhaus in Leipzig, Germany.

Boston Symphony Hall is famously reverberant. Amar Bose’s research concluded that at Symphony Hall, of the sound that reaches the listeners’ ears, 11% is direct and 89% is reflected. Therefore he designed the 901 with one forward-facing driver and 8 rear-facing drivers. 8/9ths translates to as close to 89% as you can get.

The user guide instructed owners to place the flat baffle (with one speaker) facing into the room, the 8-driver angled rear facing the wall behind it, and position the speakers with a one-foot gap between speakers and wall.

The only other reason to have the 8 drivers facing into the room is if there is no wall--or an inadequate one--behind the speakers. The combined 16 speakers on two angled baffles bringing the entire wall into play, which is why the compact 901s produce such room-filling sound.

g_yakamoto:

Back in the 70's, i read that you should have at least 100 watts per chanel for these speakers.

Yep. I would say 100 wpc in a high current amp would be the minimum, and 200 wpc is better. It's telling that Bose's own amp was 250 wpc into 8 ohms, 400 into 4.

The reason 901s were often underpowered is because in 1971 a pair of 901s plus a Phase Linear 400 plus a separate preamp would cost the equivalent of over $8900 in today's money, a bit steep for a college kid, or even a young professional. Just the Bose 901s plus a good receiver would be a lot of money by today's standards (about $5300).