bose 901 driver surround repair replacement

ingvar ahlberg said:
Hi
Imo, throw them away, was junk even before cheap foam surrounds gave up.


Great, that's really helpful (not) :p

Bose may be mostly very cheaply made "junk", but, the 901s are very impressive speakers in some ways, for their size they could play very loud cleanly and they sounded better than a lot of other commercial speakers that were available at the time.

The last time I heard them was in 1988 or so and they were driven by a pair of Carver 500 watt power amps each "bridged mono" for the full 500 watts going to each speaker and they were turned up to near clipping and the speakers output was still smooth and clear, filled a dance hall quite well with just one pair of moderately small home speakers. Sounded better than quite a few much larger PA systems I've heard throughout the years.

They might not compare to the best speakers, but that doesn't make them garbage, unless, there can not be found any inexpensive replacement drivers...

edit: Oh, now I see the previous poster's link to the surround repair kit, even better, definitely worth it if it restores the speakers to proper operating condition....
 
Sorry if i was coarse, should have been a line more.
And yes the 901 is by a wide margain the best Bose has made, so far, still i think, personally, it is a bad speaker. It sure can play extremely loud but no lf no hf, the 3" midrangedrivers are forced tho work outside their range by a mediocre equalizer. For the price of 18 new foam surrounds i think you can build a pair of nice compact speakers far superior to the 901 in all respects but loudness.
 

adason

Member
Paid Member
2004-11-10 8:31 pm
Maryland
you are both poor in mathematics
link I gave you cleary states it is 10 surrounds for the price of $39.90
20 surrounds therefore is $80 unless you buy four kits and you get the price break
in my opinion those 901 speakers were junk than and are junk now, but one man's junk is other man's treasure.
i would like to see those far superior speakers for $80 you would build, ingvar, if that would include drivers and enclosure, it would be junk for sure
 
My first post in this thread was not only unhelpful, it was downright stupid, and worse, offensive to the thread starter.jaya000. For this i sincerely do appologise. Seeing the question comes from India it would probably be worthwhile to look for replacement drivers, the same type of speaker is standard in lot´s of Audi and GM cars, those drivers are manufactured in China/India and should be very cheap if found at the right distribution level. Yes Adason, for about 80 euro, the dollar is at the moment under siege, i would build a pair of TQWT´s in birchply with Gamma bbk200 drivers and a Philips or Monacor tweeter. Would not leave any change for beer but, to my ears, more fun to listen to.
 
adason said:
you are both poor in mathematics
link I gave you cleary states it is 10 surrounds for the price of $39.90
20 surrounds therefore is $80 unless you buy four kits and you get the price break
in my opinion those 901 speakers were junk than and are junk now, but one man's junk is other man's treasure.
i would like to see those far superior speakers for $80 you would build, ingvar, if that would include drivers and enclosure, it would be junk for sure

$80 eh?

Four of these midwoofers for MTM (perhaps dipole): http://madisound.secureserverdot.com/catalog/product_info.php?products_id=1757

Two of these tweeters: http://madisound.secureserverdot.com/catalog/product_info.php?products_id=1496

Two 8" woofers for "bass bins" lower low freq. cabinets, perhaps these?: http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=299-826

The most expensive parts might end up being inductors, to save money, find some big AC motor being discarded (not too hard if you live in a big city and just watch the sidewalks for such things being thrown out) then salvage the wire and wind your own inductors. I know with the price of copper having gone up so much such things are harder to come by recently though. If you keep looking, eventually you can find some discarded copper wire...

Lots of people throw out furniture, you could use discarded drawer units/kitchen cabinets, etc. for the wood to build your cabinets to save money...

And, you could probably build something that sounds better than your typical $2,500 store bought speakers.
 
An old 901 is a great period piece. Especially if you have the funkey stands. I actually added Vifa 1" silk dome tweeters to mine and don't use the processor. They certainly don't have the fidelity of modern speakers so I keep them out in the back yard in the greenhouse. For a few bucks for foam surounds, latex glue and an afternoon, you'll have some rockin' party speakers. Remember, the flat sides go to the room and the 8 drivers on the back bounce off the wall.
 
mlise said:
An old 901 is a great period piece. Especially if you have the funkey stands. I actually added Vifa 1" silk dome tweeters to mine and don't use the processor. They certainly don't have the fidelity of modern speakers so I keep them out in the back yard in the greenhouse. For a few bucks for foam surounds, latex glue and an afternoon, you'll have some rockin' party speakers. Remember, the flat sides go to the room and the 8 drivers on the back bounce off the wall.

If you don't use the processor how do you work out the boosted low frequencies from the 901s?
 
Bose 901 drivers

Any further research/repairs done by the the originator on this thread?
FWIW, I recently listened to a pair of 901-II using both an Accuphase E-202 and a Mosfet moded Dynakit ST-120 Amplifiers...these clearly revealed the limitations in the 901 box/driver combo. Can't point any fingers to Bose, but need to admit the 70's technology/knowledge base on hand to put together sound boxes cannot compete with what you can do today with relatively less investment. Speaker design technology is now at the point where anyone so inspired can put together some pretty decent sound reproducers..question is how can one be certain of starting off with "good" drivers.
The Bose 901 series II drivers (all 18 of them from two boxes) are only good to experiment with. The ones I extracted from my boxes have been tested for TS parameters..since I plan to put together something different than the 901 style acoustic suspension box for these drivers. So far, I have just started considering what mods I need to make on the drivers...since these have cloth surrounds (Bose slightly sealed the cloth with a tacky substance), and paper cones that need to be sealed.
The listening session at the onset indicated a mid frequency boxy sound and lack of the high end response....both of which, IMO, should not be "improved" electronically using the 901 Active Equalizer (my ear-brain link does not like).
FYI, the drivers have Fs around 75Hz, Re=7.0 ohms, Vas=6 to 7.5L, Qe=0.34, Qm=1.6, Le=0.45 mH, ...these are average values
I will probably add weight to the diaphragms in search of a lower Fs (PVA coating and split lead sinkers as used many times by John Crawford reporting in Speaker Builder).
If interest appears, I will follow with progress in due time...I am running many rabbits (retiree)
Louis