We are repeating ourselves Gentlemen.
http://www.diyaudio.com/forums/multi-way/243702-describe-original-bose-901-driver.html#post3657915
http://www.diyaudio.com/forums/multi-way/243702-describe-original-bose-901-driver.html#post3657915
Report on the Bose I picked up a week ago (drove 100 miles r/t for "free shipping!"). As advertised, it is a defective pair. The cabinets are ok (I needed a set). Both speakers are dead opens. I have disassembled one cabinet so far. Of five drivers, 4 are open, 1 good (7.2 ohm). One speaker was cracked, a few more cracked with flexing. Of 4 "original" sets of Bose 901 I, II I have seen, this is the only/most damaged one I have ever had. Perhaps it was wired in series with a lightning rod? 
Here is a DIY question: is it worth (possible?) to re-cone or repair these old drivers? I am assuming an "open" on a speaker means the voice coil is fried rending everyhthing useless?
Here is a DIY question: is it worth (possible?) to re-cone or repair these old drivers? I am assuming an "open" on a speaker means the voice coil is fried rending everyhthing useless?
How deep are your pockets?
4-1/2" Replacement Speaker Full Range, Mid Range, Paper Cone, Foam Edge, 8 Ohm
4-1/2" Replacement Speaker Full Range, Mid Range, Paper Cone, Foam Edge, 8 Ohm
Better build something new with one decent fullranger instead of four budget drivers.
The Madisound Speaker Store
I once made experiments with one fullranger per side facing the wall 30° inwards or outwards. Works. I guess the reason for using four per side was that no decent large format fullrangers were available in the US at that time. The same speaker in Europe would have been equipped most likely with 8" Philips drivers like the 9710.
The Madisound Speaker Store
I once made experiments with one fullranger per side facing the wall 30° inwards or outwards. Works. I guess the reason for using four per side was that no decent large format fullrangers were available in the US at that time. The same speaker in Europe would have been equipped most likely with 8" Philips drivers like the 9710.
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Well, stack about 4 of them per side, each with their own Phase Linear 400 to power it... place in a room with at least one "old school" plaster/lath wall.
Write home...
You might be able to find acceptable replacement driver for less...
...but at a certain point one just quits the 901 bandwagon and goes ahead and builds their own line array...
...in essence that is the exact path that I took, except that were talking the 1970s. The first step was a modified "Bose" concept, two not four drivers wide in the back, which made it taller, and with better dispersion and better line source. Then the next step was the speaker shown in the Polaroid attached. WAY better.
If you like the Bose you'd most likely prefer a big line source.
Parts Experess has come up with some jim dandy cheap good drivers for line sources recently.
Write home...
You might be able to find acceptable replacement driver for less...
...but at a certain point one just quits the 901 bandwagon and goes ahead and builds their own line array...
...in essence that is the exact path that I took, except that were talking the 1970s. The first step was a modified "Bose" concept, two not four drivers wide in the back, which made it taller, and with better dispersion and better line source. Then the next step was the speaker shown in the Polaroid attached. WAY better.
If you like the Bose you'd most likely prefer a big line source.
Parts Experess has come up with some jim dandy cheap good drivers for line sources recently.
Attachments
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Most people who slam 901's have never heard them set up properly. Bose doesn't even bother setting them up properly in their stores.
I find it funny and yet sad that people knock the speaker. the 4" CTS driver is highly valued for those of us that enjoy a 50 watt 4" driver with a FS around 75hz and a high end solid to 10k. They make very good full range drivers.
The new 4" drivers being only 1 ohm I have no use for.
I find it funny and yet sad that people knock the speaker. the 4" CTS driver is highly valued for those of us that enjoy a 50 watt 4" driver with a FS around 75hz and a high end solid to 10k. They make very good full range drivers.
The new 4" drivers being only 1 ohm I have no use for.
Yes but let's consider their validity, the 901's had their time, right? So did the 800 series in the pubs.
Thanks, but you are offering opinions to those who might be as versed as you and I don't bash them, I realize their limitations. That's as nicely as I can put it.
How deep my pockets? Not very. Would I be buying broken Bose 901s for $99 otherwise? Actually I like them because (unlike new Bose) the very old ones are cheap and (for what they are) they do it well. Last week's buy has yielded 5 maybe-good drivers (at least read 7-8 ohm), about 5 torn cone, and the rest dead opens. Also two reasonably good cabinets (what I really needed.) Is the verdict to junk the bad drivers? That is my inclination. Is a war starting soon? I can save them for the scrap metal drive!
Yes, by all means for the war effort!
Parts Express had some rather nice drivers in the <$2.00 per driver range, for the frugal builder of line arrays it pays to keep an eye out for bargains. I think Madisound had or may still have some Aura drivers too at blowout prices.
In fact you'd be really surprised at what a pile of cheapo "TV/computer" speakers will do in a line array if you get enough of them together, and they are reasonably flat to start with...
Of course you need some woodworking ability/tools to make that fly, but I'd suggest that you might consider that route as a possible way to go.
The thread on using foam board for speaker cabinets might have come up with a way to do that, so that drops the requirements down to a razor knife and a straight edge + a circular cutout shape for the holes... fwiw.
_-_-bear
Parts Express had some rather nice drivers in the <$2.00 per driver range, for the frugal builder of line arrays it pays to keep an eye out for bargains. I think Madisound had or may still have some Aura drivers too at blowout prices.
In fact you'd be really surprised at what a pile of cheapo "TV/computer" speakers will do in a line array if you get enough of them together, and they are reasonably flat to start with...
Of course you need some woodworking ability/tools to make that fly, but I'd suggest that you might consider that route as a possible way to go.
The thread on using foam board for speaker cabinets might have come up with a way to do that, so that drops the requirements down to a razor knife and a straight edge + a circular cutout shape for the holes... fwiw.
_-_-bear
IMHO the effect of drivers facing the wall in low distance is quite unique and can't be approximated by standard designs.
Original CTS driver information
Bose Series 1 (1968-73) and Series 2 (1973-76) were acoustic suspension design. Series 1 had gray paper cones and Series 2 had gray and I believe eventually at some point blue cones. I have a series 1 set with a serial # 141176 and 141196 with gray cones, marked with following on magnet structure: 25-100441/24729/2857310E. These were made by CTS with paper cone, with butyl impregnated cloth surround, and original part number was model 4.5SR10B. I believe CTS was out of Brownsville, TX at that time. I bought these without EQ for $100 (pair) a few years ago, and the drivers still work. I took them out and integrated the drivers into a pair of 8' line array cabinets I was experimenting with, so one side has 15 of these CTS drivers. I EQ them with a dbx Driverack PA digital unit, and for a 1971-72 driver, they still work very well. Although this was not the most efficient driver at the time, It was still probably in the high 80's(db sensitivity). How many drivers made in 1972 can still work today?
I am a devoted DIY experimenter with pretty much all speaker types over the years (direct, point source, line source, horns, ESL, planar magnetic, etc, from 2 way mini-monitors to 4 way D'Appolito leviathans), and I do believe that all the Bose bashing is for the most part, non-constructive for a forum of this caliber and uniqueness. It is true that Dr. Amar Bose created a company that was strong on marketing techniques and flashy (and sometimes incredible) advertising of middle-of-the-road sound quality, but it is important to understand that he was first and foremost, an R&D professor guy who liked to experiment, and his products reflect that. What he came up with in 1968 was a very novel design for the time that had (and has) a unique and very diffuse soundfield. And certainly even then, J. Gordon Holt did not care for it from an audiophile perspective, and I would have to say my old pair of antique AR4X's probably come closer to the absolute sound . But I believe it is better to look at these things from an engineering perspective and say that it had a place in audio history, it fulfilled a certain niche in the audio market, and leave it at that. If some want to take up the grail and possibly take that design to the next level, who am I to squash their dreams? With all the recent advancements in full range line array design and DPS control that are making waves, maybe the old 901 full range/equalized/direct/reflected concept isn't so out of date as we originally thought. Face it, we are in a sort of a second golden age of discovery(the first would have been the 1950's and 1960's), where some of the neatest new leading edge stuff is found on internet web sites like this one, so let's be an incubator of new high fidelity technology, and nurture each other in trying out new designs that might be tomorrow's state of the art in high fidelity sound. For those of you already doing that on these forums, I applaud you. I remember when Compact Disc first came out, many were quick to condemn the LP vinyl technology as outdated, with pops, clicks, record warp, rumble, et al, but look at the vinyl resurgence of today. Just my 2 cents, of course.
Bose Series 1 (1968-73) and Series 2 (1973-76) were acoustic suspension design. Series 1 had gray paper cones and Series 2 had gray and I believe eventually at some point blue cones. I have a series 1 set with a serial # 141176 and 141196 with gray cones, marked with following on magnet structure: 25-100441/24729/2857310E. These were made by CTS with paper cone, with butyl impregnated cloth surround, and original part number was model 4.5SR10B. I believe CTS was out of Brownsville, TX at that time. I bought these without EQ for $100 (pair) a few years ago, and the drivers still work. I took them out and integrated the drivers into a pair of 8' line array cabinets I was experimenting with, so one side has 15 of these CTS drivers. I EQ them with a dbx Driverack PA digital unit, and for a 1971-72 driver, they still work very well. Although this was not the most efficient driver at the time, It was still probably in the high 80's(db sensitivity). How many drivers made in 1972 can still work today?
I am a devoted DIY experimenter with pretty much all speaker types over the years (direct, point source, line source, horns, ESL, planar magnetic, etc, from 2 way mini-monitors to 4 way D'Appolito leviathans), and I do believe that all the Bose bashing is for the most part, non-constructive for a forum of this caliber and uniqueness. It is true that Dr. Amar Bose created a company that was strong on marketing techniques and flashy (and sometimes incredible) advertising of middle-of-the-road sound quality, but it is important to understand that he was first and foremost, an R&D professor guy who liked to experiment, and his products reflect that. What he came up with in 1968 was a very novel design for the time that had (and has) a unique and very diffuse soundfield. And certainly even then, J. Gordon Holt did not care for it from an audiophile perspective, and I would have to say my old pair of antique AR4X's probably come closer to the absolute sound . But I believe it is better to look at these things from an engineering perspective and say that it had a place in audio history, it fulfilled a certain niche in the audio market, and leave it at that. If some want to take up the grail and possibly take that design to the next level, who am I to squash their dreams? With all the recent advancements in full range line array design and DPS control that are making waves, maybe the old 901 full range/equalized/direct/reflected concept isn't so out of date as we originally thought. Face it, we are in a sort of a second golden age of discovery(the first would have been the 1950's and 1960's), where some of the neatest new leading edge stuff is found on internet web sites like this one, so let's be an incubator of new high fidelity technology, and nurture each other in trying out new designs that might be tomorrow's state of the art in high fidelity sound. For those of you already doing that on these forums, I applaud you. I remember when Compact Disc first came out, many were quick to condemn the LP vinyl technology as outdated, with pops, clicks, record warp, rumble, et al, but look at the vinyl resurgence of today. Just my 2 cents, of course.
I wouldn't lump the 901 in with line arrays by any stretch. Line arrays are an excercise in increasing directivity through coherrent summing of multiple drivers at the listeners position. The 901 was about doing the opposite, increasing reflected energy. The 901 has a negative irectivity index, a very unique attribute.
Any Bose Engineers that are members of diy Audio? (I have a personal reason for asking)
David
Any Bose Engineers that are members of diy Audio? (I have a personal reason for asking)
David
I wish I had saved the several bad 901 drivers that I threw out weeks ago. I might have been able to make one of these. "DIY-cat-toy"? It is an example of a cat toy my cats (4) actually like.
Cataction Magneticat Cat Toy at PETCO
Cataction Magneticat Cat Toy at PETCO
A late addition to the thread but here are two sources for likely current replacement drivers for your original 901:
GRS 4FR-8 Full-Range 4-1/2" Speaker Pioneer Type A11EC80-02F 8 Ohm
Or for double the price from the mysterious Orient
4 inch 50 w 8 ohm Audio subwoofer speakers For Midrange Bass computer speaker Freeshipping-in Consumer Electronics on Aliexpress.com
If you don't mind bottom fishing (and driving) i still aver the best source is old 901s to scavenge.
GRS 4FR-8 Full-Range 4-1/2" Speaker Pioneer Type A11EC80-02F 8 Ohm
Or for double the price from the mysterious Orient
4 inch 50 w 8 ohm Audio subwoofer speakers For Midrange Bass computer speaker Freeshipping-in Consumer Electronics on Aliexpress.com
If you don't mind bottom fishing (and driving) i still aver the best source is old 901s to scavenge.
Sigh.. I foolishly (naively ) bought 901 's when they were "new'.
Expensive buys into what eventually proved to be a Bose trademark.. Wayyy too many $$ for quality received.
Arguably (opinions varied, even then) they were decent IF their sounds were bounced off a solid concrete wall 'backstop'.
Not surprisingly the average customer did Not have one of those tho.
Long dead issue imo.
WHY !? Is this rewriting of history even being talked about?
You bought Junk ..Mate.... deal with it.
Expensive buys into what eventually proved to be a Bose trademark.. Wayyy too many $$ for quality received.
Arguably (opinions varied, even then) they were decent IF their sounds were bounced off a solid concrete wall 'backstop'.
Not surprisingly the average customer did Not have one of those tho.
Long dead issue imo.
WHY !? Is this rewriting of history even being talked about?
You bought Junk ..Mate.... deal with it.
I had a stereo setup with a Denon stereo receiver, Bose 901s, and Klipsch sub12. It was in a brick turn of the century apartment with 10ft ceilings. when listening to Zep or Pink Floyd in stereo it sounded amazing at 40db (denon volume). to me they sounded more natural or softer than conventional speakers. I could be in the kitchen or back bedroom and they sounded about the same as in the living room.
coming into 2014, I live in a small 1 BR house from the 1950s. I have a pair of B&W 685 bookshelf speakers for stereo L/R toed in to my favorite chair. when sitting in the chair and the volume set to 30db they sound pretty good but I dont get that wrapped in a warm blanket sitting next to a fire comfort feel I once had with the 901s. If I go into another room the sound is almost lost. each person has their own personal preference on what sounds good. IMHO they both sound good in their own rights they just sound different. If I didnt pay $500 on ebay for the 901s I would have a different perspective.
coming into 2014, I live in a small 1 BR house from the 1950s. I have a pair of B&W 685 bookshelf speakers for stereo L/R toed in to my favorite chair. when sitting in the chair and the volume set to 30db they sound pretty good but I dont get that wrapped in a warm blanket sitting next to a fire comfort feel I once had with the 901s. If I go into another room the sound is almost lost. each person has their own personal preference on what sounds good. IMHO they both sound good in their own rights they just sound different. If I didnt pay $500 on ebay for the 901s I would have a different perspective.
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