I would like to know how the nine speakers in a bose 901 ser2 speaker are wired up inside. from what I had found out so far the drivers in the ser 1 and ser 2 were 8ohm now with nine drivers to hook up in each speaker if they were all hooked up plus to plus neg to neg it would be a reactive loadand all plus to neg well your load would be very large indeed. So how did they do it without blowing up amps? something else if they used a combonation of the two to fix the load would this not lead to one driver killing the bass of the one beside it (out of phase)? please if you can help with this thanks.
yours Jack G.
- Bose 901 Series I and II speakers have 8 Ohm impedance each.
- A row of 3 speakers in series gives you 24 Ohm.
- 3 parallel rows gives you finally 8 Ohm.
Front with 8 speakers (view from the rear):
(1) (3) (5) (7)
(2) (4) (6) (8)
Rear speaker is number (9)
Row 1: -(1)+ -(3)+ -(7)+
Row 2: -(5)+ -(9)+ -(2)+
Row 3: -(8)+ -(6)+ -(4)+
The Active Equalizer uses standard garden variety stereo RCA cables.
http://www.bose.com/pdf/customer_service/owners/og_901.pdf
Here is the wiring diagram
I have a pair of the 901 and the active equalizer but they have been in the closet for 6 years. I tried hooking them up without the equalizer and they did not sound good at all. I need to find a set of wires for the equalizer. Is this a special order or should Radio Shack carry them? Also how much would it cost to get the pair refoamed?
any help is appriciated.
bose 901 are great but misunderstood speakers. they use the back wall, side walls, floor, and ceiling as a giant horn (or waveguide, in Bose speak). If you don't have five square flat reflective walls to bounce the sound off of, they won't work as designed, and won't sound good.
If you DO have the room and walls for the 901s, then follow the directions on how to place them, and put on some music. If you A-B the 901 with another type of speaker, you're likely to think the 901s sound muffled, with little high-end. but ears are interesting things, and if you stop switching back to the "normal" speaker, your ears will adjust to the tonal balance of the 901 and the high-end will emerge fully after about 30 minutes. It will be at this time that you realize that the source of the sound appears to be coming from out past the back wall - somewhere between 8 and 50 feet past it, in fact, depending on your room dimensions and where you placed the 901s. the effect is absolutely stunning, and no other pair of home speakers I know of can replicate this sound stage. Thats the Truth about the 901. Anybody who says they're no good has missed the point.
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If I remember correctly, the 9 X 4.5" drivers (for each speaker) are 0.9 ohms each impedance. They are wired in series, thereby achieving an 8.1 ohm impedance per load speaker (9 * 0.9 = 8.1). The active equalizer for the speakers produces a response curve necessary for reproduction of rich bass and high which deteriorates due to the combination of full range drivers wired in series. Larger amps ( > 60WPC) are usually necessary for Series one and two pairs to reproduce better bass. I don't recommend anything after the series 2, as the sound just seemed to get progressivly worse to increase efficiency, so that smaller amps would be needed. Just get yourself a nice HK 2-channel receiver, and your series 2's will sound alright so long as your room is *perfect* for sound reflection, and your speaker surrounds (cloth in the series 2) are in good shape.
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I have a set of Bose 901's and I have replaced the Foam edges on eight of the 9 drivers with great success. However, I cannot gain access to the 9th speaker the front one due to the front grill being removable. These speakers are a old Series V set.
Any suggestions would be greatly appreciated.
Corry
why are we even having this discussion.... bose sucks
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