901 series 2 speakers

asvjerry wrote:

I had a pair of 901/2's way back when. Drove them with a Marantz 2270 that when cranked, the dial lights would pulse with the bass line....

When the 901s came out, people were pretty naive about how much power they really required. Quite often they were paired with a Marantz or Pioneer receiver making 40-50 wpc. What people didn't know is the effect of the "Active Equalizer" had something like a 20dB boost at 50 Hz to impart some credible bass. That was quite a strain on an a typical--even a good--receiver at that time. Those with more money might pair it with a Phase Linear 400 or an SAE powerhouse. You might say Bose "came out of the closet" regarding power requirements when they produced the Bose 1801 power amplifier, a behemoth putting out 250/400 wpc into 8/4 ohms. *That* really lit up the 901s and showed what they could do when fed some serious power and current.

Not surprised that Bose later offered them as PA drivers, pointing the back 8 at the audience and saying the front single could be used as a stage monitor. 

Actually, the Bose PA speakers were the 800 series, starting with the 801 and soon on to the 802. The configuration *did* turn the Bose enclosures around so the 8 drivers faced the audience, but there was no single driver on the back side. The 800 model had a pair of large ports in the back; the 802s moved those ports to the front and managed to fit all eight 4-1/2" drivers in the angled front as well.

... Often thought if you stacked, say, a dozen of them per side that they'd be an insane line source....

In the 1970s I saw a multimedia presentation that used some really powerful amps (I forget which--probably Crown DC300As or Bose 1801. They used 3 pairs of Bose 800 speakers stacked and facing the audience in a mid-size venue. Those things played loud and clean. They also had the advantage of 48 full-range drivers with no crossovers, facing the audience. The midrange was crystal clear (ideal for dialogue) with seemingly unlimited (for 1976) dynamic range.

g_nakamoto writes:

hi, anybody out there have any thoughts of the bose 901 series 2 speakers?

A few years ago, Jeff Dorgay, editor/publisher of ToneAudio, did a fresh review of the Bose 901 Series VI loudspeakers with the same methods that would be used to review speakers today. For example, he used top quality Sound Anchor stands, high quality speaker cable (that won't fit in the narrow columns of Bose's pedastals), and a range of amplifiers, from a vintage Pioneer SX-424 to a Unison Research S6 vacuum-tube amp to a pair of Pass Labs XA200.5 monoblocks.

Read the review; I think you'll find it enlightening. He considered it a competitive value at its $1400 (new, retail) price an a lot of fun for many applications.

Dorgay owns and frequently reviews some seriously high end gear. 

To put some things in perspective, the 1st gen 901s retailed at $476 in 1971. Adjusted for inflation that would be $2874 in today's money. But today the Bose 901 Series VI retails at $1400, which would only amount to $232 in 1971.

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).