Seems that everyone has an opinion of the Bose 901 and most ( on this forum ) seem to be very negative, I am a huge fan of the 901 design but not the way they are made or the EQ or the cheap drivers if you build a modern 901 with sealed cabinet made of MDF with 1-1/2 baffles and one inch side and tops and use the best 14ga wire for internal wiring and use one of the most modern and wide range drivers available and use an EQ just to lightly fine tune the setup, maybe that would change your opinion of the design. I did all that ( with the help of Meniscus audio in 1989 ) well everything except state of the art drivers which are incredible now.
Guess my point is that the 901 were designed by a M.I.T Graduate who had to borrow money to start Manufacturing them and the Majority of the buying public enjoyed the sound, which led to other products which led to a SELF MADE BILLIONAIRE , not sure any other speaker Manufactures can say that. this guy was a Genius. The real problem came along in the name of J.Gordon Holt of Stereophile magazine, he liked most of it but trashed them at the end of the review , not sure if he was an M.I.T Graduate or an Engineer or just a Guru who sold magazines.
Anyway, Amar G Bose was a speaker builder who took his design and set the world on fire...........no one on this site or any other site can say that...unless you too became a self made Billionaire from your design.
Guess my point is that the 901 were designed by a M.I.T Graduate who had to borrow money to start Manufacturing them and the Majority of the buying public enjoyed the sound, which led to other products which led to a SELF MADE BILLIONAIRE , not sure any other speaker Manufactures can say that. this guy was a Genius. The real problem came along in the name of J.Gordon Holt of Stereophile magazine, he liked most of it but trashed them at the end of the review , not sure if he was an M.I.T Graduate or an Engineer or just a Guru who sold magazines.
Anyway, Amar G Bose was a speaker builder who took his design and set the world on fire...........no one on this site or any other site can say that...unless you too became a self made Billionaire from your design.
Anwar Bose certainly Was was a genius... at Marketing his Mediocre products.
No More, No less.
Sure you can spend large on Better Bits.. Fill yer boots.
But you will STILL need the massive concrete wall backstop to make the design and theory of 901's work as claimed.
Bose was famous... for his 'claims'.
It's over ... get used to it.
No More, No less.
Sure you can spend large on Better Bits.. Fill yer boots.
But you will STILL need the massive concrete wall backstop to make the design and theory of 901's work as claimed.
Bose was famous... for his 'claims'.
It's over ... get used to it.
Should the 901 be a topic blacklisted from DIY Audio forums?
I have heard / sold them them, and in another life time even used them as disco/PA system (2 stacked pairs powered by Crown DC300), so certainly have my own opinion as to their performance qualities, but they are one of those hot button topics that devolve into near religious tautology.
I have heard / sold them them, and in another life time even used them as disco/PA system (2 stacked pairs powered by Crown DC300), so certainly have my own opinion as to their performance qualities, but they are one of those hot button topics that devolve into near religious tautology.
Nah! It's just too much fun bashing the 901's. You know what's even funnier, you can still buy them.
jeff
"Should the 901 be a topic blacklisted from DIY Audio forums? "
No only those who cut them down should be blacklisted the people who want to discuss them always seem to get some NON Acoustic Engineer self proclaimed expert to jump in and wreck the thread. looking for attention I guess, I don't jump into a full range or Transmission line thread just to trash the speaker and leave.
No only those who cut them down should be blacklisted the people who want to discuss them always seem to get some NON Acoustic Engineer self proclaimed expert to jump in and wreck the thread. looking for attention I guess, I don't jump into a full range or Transmission line thread just to trash the speaker and leave.
Read his review, he said that they were unexceptional other than the effect of spaciousness, which was an artifact not in the recording.
Well Stereophile DID have many good things to say about the 901 all from the article here www stereophile com/standloudspeakers/425/
And here are the excerpts :
The 901 sounds fantastically open and spacious, with a big, fat low end and a socko you-are-there presence that seems to put the performers right in the room, surrounded by the original auditorium.
We were duly impressed by these qualities, too, and reported this in our preliminary report in the last issue.
the 901 speakers are less critical of room placement insofar as stereo imaging is concerned than are most other systems
It is probably fair to say that the 901 actually exaggerates spaciousness from recordings, rather than reproducing it as it is contained in the recording. But since two-channel stereo reproduction is inherently deficient in spatial qualities anyway, it must also be said that the net result is an improvement in realism.
The 901 does not synthesize the added spaciousness, though; it merely enhances what is already on the recording. Thus, a recording made outdoors will not be imbued with concert-hall spaciousness, but is instead made to sound even more convincingly outdoorsy. And a recording with no spatial information on it at all, like a mono one, will sound somewhat diffuse but will have virtually no more spaciousness than it would through any other speaker system.
the 901 yields as stable a stereo image as any speaker we have tested.
the 901 is able to put out really respectable levels (even on bassy program material) without offensive distortion when driven by a modest 35Wpc
The effectiveness of high frequency boost is open to some question, too. Theoretically, any device that has had its high end boosted, to yield the same treble response as an unequalized device, should have the same treble performance on musical signals
We don't wish to give the impression, though, that the 901 is a dull-sounding system
the 901 has much of the brilliance of a typical horn system, but without the "horny" midrange coloration.
If we were to judge the 901 in terms of the best sound available, then, we would say that it produces a more realistic semblance of natural ambience than any other speaker system
So yes they did have good points to make on the 901
And here are the excerpts :
The 901 sounds fantastically open and spacious, with a big, fat low end and a socko you-are-there presence that seems to put the performers right in the room, surrounded by the original auditorium.
We were duly impressed by these qualities, too, and reported this in our preliminary report in the last issue.
the 901 speakers are less critical of room placement insofar as stereo imaging is concerned than are most other systems
It is probably fair to say that the 901 actually exaggerates spaciousness from recordings, rather than reproducing it as it is contained in the recording. But since two-channel stereo reproduction is inherently deficient in spatial qualities anyway, it must also be said that the net result is an improvement in realism.
The 901 does not synthesize the added spaciousness, though; it merely enhances what is already on the recording. Thus, a recording made outdoors will not be imbued with concert-hall spaciousness, but is instead made to sound even more convincingly outdoorsy. And a recording with no spatial information on it at all, like a mono one, will sound somewhat diffuse but will have virtually no more spaciousness than it would through any other speaker system.
the 901 yields as stable a stereo image as any speaker we have tested.
the 901 is able to put out really respectable levels (even on bassy program material) without offensive distortion when driven by a modest 35Wpc
The effectiveness of high frequency boost is open to some question, too. Theoretically, any device that has had its high end boosted, to yield the same treble response as an unequalized device, should have the same treble performance on musical signals
We don't wish to give the impression, though, that the 901 is a dull-sounding system
the 901 has much of the brilliance of a typical horn system, but without the "horny" midrange coloration.
If we were to judge the 901 in terms of the best sound available, then, we would say that it produces a more realistic semblance of natural ambience than any other speaker system
So yes they did have good points to make on the 901
My interest is not in making a clone it is of taking in all the gathered info I have good and bad and building an Audiophile version of it , not to please others but to please me. This can be accomplished by using the state of the art drivers best wiring best terminals best cabinet. Bose in the store bought version IS not mid-fi but low or no-fi based on how they are made. this is what makes this hobby fun and a real challenge
Audiophile Version
If you don't think it's heresy...KLH made a nice competitive version not long after the 901 was launched. A little larger cabinet, but using approximately the same geometry. KLH used three two-way sets. One set in front, one set on each of the rear facing angled panels. I think they were all 6 1/2" w/tweeter, but the front could have been a 5" w/tweeter. No EQ box. Sounded nice when I heard it at Summer CES in Chicago about 30+ years ago.
If you don't think it's heresy...KLH made a nice competitive version not long after the 901 was launched. A little larger cabinet, but using approximately the same geometry. KLH used three two-way sets. One set in front, one set on each of the rear facing angled panels. I think they were all 6 1/2" w/tweeter, but the front could have been a 5" w/tweeter. No EQ box. Sounded nice when I heard it at Summer CES in Chicago about 30+ years ago.
I've been playing with such a concept recently: Replaced the front driver with a 4 ohm version and am using a separate amplifier for it. Full DSP for front elements and back elements. Back elements replicate a concert hall balance. Front element is well equalized to direct field flat.
Sounds interesting.....
Of course with better wires and connectors it would be so good that I couldn't stand it....
David S.
I'm using an 18th order filter on the front element and it EQs nicely. No fried egg sound in this case. You do need to stay in the very narrow sweet spot but that isn't a problem. This is more of a test bed for experimentation with direct and reflected sound, rather than a universal speaker system.
Still, it sounds better than I would have predicted. (And they pay me to play with this!)
David
Well first I am looking at choosing the right drive unit that would require the least amount of equalization , lowest fs smoothest response curve and in this day and age the choices seem plentiful and at the top of the list so far is the Tang Band W5-1611SAF 5" Full Range Speaker.
Nominal Diameter 5"Power Handling (RMS)28 Watts
Power Handling (max)56 Watts Impedance8 ohms
Frequency Response 60 to 20,000 Hz Sensitivity 90 dB 1W/1m
Voice Coil Diameter 1"Magnet Weight 18.6 oz.
THIELE-SMALL PARAMETERS
Resonant Frequency (Fs)60 Hz DC Resistance (Re)6.3 ohms
Voice Coil Inductance (Le)0.02 mH Mechanical Q (Qms)2.8
Electromagnetic Q (Qes)0.52
Many more to choose from this is just the first one I have landed on that I really like , if I can believe that curve that TB shows it looks overly smooth to me.
Nominal Diameter 5"Power Handling (RMS)28 Watts
Power Handling (max)56 Watts Impedance8 ohms
Frequency Response 60 to 20,000 Hz Sensitivity 90 dB 1W/1m
Voice Coil Diameter 1"Magnet Weight 18.6 oz.
THIELE-SMALL PARAMETERS
Resonant Frequency (Fs)60 Hz DC Resistance (Re)6.3 ohms
Voice Coil Inductance (Le)0.02 mH Mechanical Q (Qms)2.8
Electromagnetic Q (Qes)0.52
Many more to choose from this is just the first one I have landed on that I really like , if I can believe that curve that TB shows it looks overly smooth to me.
Attachments
From my relatively brief exposure to the 1611, I'd describe them as "as smooth as the graph might imply" - in other words I found they had great bass extension and weight, but were a bit shy at the top couple of octaves -compared to say a Fostex FF125WK or Alpair 7.3 or 10.3. Of the few TB's Ive heard, I was much more impressed by the W4-1879 - albeit at almost 3 times the cost.
My personal opinion of the 901 and Bose in general aside, if your goal is to pay homage to the concept with modern gear, I think it's fair to say that you could get there with far less than 9 drivers per side, and of course with DSP, the EQ and room correction is far more affordable and flexible than 45yrs ago.
My personal opinion of the 901 and Bose in general aside, if your goal is to pay homage to the concept with modern gear, I think it's fair to say that you could get there with far less than 9 drivers per side, and of course with DSP, the EQ and room correction is far more affordable and flexible than 45yrs ago.
It's hard to believe TB curves are so smooth, look at a Mark audio unit or Fostex or Dayton and it looks more realistic not as perfect as TB in fact all the drive units I have looked at show a more realistic slightly bumpy ride from 60hz to 20khz. Then again TB units get mostly very good reviews , when I find the ultimate driver I am going to buy 2 and use them for my computer speakers , single driver per box and see how I like them.
Only have one Amp left a Crown K2 my favorite
Only have one Amp left a Crown K2 my favorite
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That would be an option using fewer drive units, but the original design was 89% reflected sound and 11% direct sound so as to replicate the same percentages of sound found in a typical concert hall. 8 drivers in the rear and one in the front Approximately 89% and 11% . So that is why I am doing the 9 driver cabinet besides that I have built about 12-14 of the 901 cabinets the way I felt they should be built NOT clones back in the late 80s early 90s ( pre-divorce ) and am actively looking for new ideas on cabinet construction, I would like to take a set of new blueprints when I have settled and go some place that has CNC service , The MDF machines really nice and absolute perfection is what I am after.
Of course the 89%, 11% is an unjustified number. In any concert hall the ratio of direct to reflected is largely related to your distance from the orchestra and can't be defined other than in gross generalization. (and the reverberant field is captured on the recording, no?) Sending more energy backwards than forwards is not the best solution. I have been playing with about -6dB for the back side contribution vs. the front and that sounds about right. The stock 901 sends about +9 dB to the back wall, or a minus 9 directivity index, a lot more reverberant than even a full Omni speaker.
But each rear panel is angled at 30 degrees, not all energy would be displaced in the same direction only about 4.5 db per angle . or is this incorrect ? always thought the rear panel 30 deg angles were for dispersion first and imaging second ? never read anything alluding to the why for the rear angles except what was said in Amar G Bose AES paper "sound recording and reproduction parts 1 & 2"
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