"Jonathan Livingston Seagull" Theatre Sound System Competition

[soundminded]

Many of Bose's "innovations" are exploitations of already known technologies, sometimes in novel ways. For example, Bose 901 is technically an "array" type speaker system with a few novel twists including using it largely reflectively. Bose wasn't the first one to deliberately reflect sound, JBL did it with Paragon for example. Equalization was also a known method for improving speaker performance. The synergy of these technologies and the incorporation of them in practical, easy to use, affordable products still required a great deal of inventiveness and R&D. Likewise the application of transmission line theory to a table radio to extend bass was a novel application of an existing idea. So was the use of a "subwoofer" and satellites as Infinity had done with Servo-Statik I and IA but on a different scale.

Bose 901 represents possibly the only serious effort, certainly the only one I am aware of to integrate a loudspeaker into the acoustics of a listening room. Frankly most manufacturers ignored the listening room paying lip service to it at best. It was of course only a partial technical success but at least it was an effort and unquestionably a marketing success. It's interesting that not only do manufacturers of loudspeakers continue to try to defeat room acoustics, they never even consider the alternative. Therefore we have speakers today which try to restrict dispersion of sound to the greatest degree posible. Unless you live in an anechoic chamber this is of course a hopeless effort.

I've concluded that the study of acoustics is largely a mechanical engineering problem dealing with a specialized branch of mechanical engineering called fluid mechanics, fluidics, or transport phenomena, the fluid being air. The electrical engineering problems associated with sound recording and reproduction have been solved a long time ago and IMO are now trivial. Fluid mechanics is an extremely difficult subject to master. The equations in their full blown state are every bit as complex and daunting as those nasty negative feedback equations. So perhaps one reason all progress in this area has stopped is that the wrong people with the wrong skill sets are working on it. Anyway, it's fun to work on a problem with a novel approach nobody else seems to feel is worth trying and of course getting very different results.

[Guest boseguy]

It’s interesting—and very telling—the amount of attention being paid to the 901 by the Forum members. Internally at Bose when I was there, the 901 was already past its prime, a product from an earlier era that we wanted to keep current because of how much it meant to our history and public image. Even in its heyday, it was a difficult product for many people to hook up (because of the equalizer) and use. Its placement demands further hindered its widespread distribution. And remember, for its entire product life, it has resided at the high end of the price spectrum, not in the Advent/KLH-6 region. So while the 901’s dollar sales totals may be high, its unit sales weren’t. I used to have Bose sales stats by model from 1968-1991; I don’t think I still have them, but if the Advent sold 1,000,000 units over its life, the 901 was never in that category.

When I was there, the AM-5, 201, 301 outsold the 901 in unit sales by a 50-1 ratio. And the AM-5 was not that much cheaper--$750 for the set compared to $1376 for the 901. The 901 was a very small seller by 1990.

There was an internal marketing directive at Bose that whatever top-of-the-line product Bose came out with, it would have the designation “901.” So even if the original 901 were to be replaced by a completely new speaker, the “901” identifier would remain. It was an amazing show of corporate pride that “901” would always be the name, because the original 901 from 1968 was the product that established the company. But in all seriousness, by the early '90's, internally at Bose, the 901 wasn’t a high-visibility product. We called ourselves the “AM-5” company; later we ‘feared’ we’d turn into the Wave Radio company. The Forum members are a great group of enthusiasts and historians, but you give the 901 far more attention and credit than we did at Bose. It was a largely forgotten item by 1990, kind of kept on marketing life support purely because Bose didn’t want to discontinue its ‘founding’ product, even though it had long since passed its sales peak. Make no mistake, we always believed the performance and build quality of the 901 was excellent; we just came to realize that from a market viability standpoint, it was no longer a great fit.

Customer Service, was, as noted before, a cornerstone item at Bose. When the original Lifestyle Music System was about to be introduced in 1990, we found a potential defect in the production lot. Now, remember, the Lifestyle System was a huge departure for Bose, their first real venture in turning the company in a new direction The AWMS was a direct sales item; the Lifestyle was a retail item, and was heralding an entirely new product direction for the company. It was a huge deal.

We delayed the initial shipment of the product in order to re-check 100% of the inventory to be sure they were ok before they went out. This was in the holiday shipping season of 1990! How many companies would delay shipment of millions of billable dollars of goods just because some tiny percentage showed a possible minor problem? Very few, I can assure you.

However, Bose made sure they were all perfect. Turned out that only very few units had any problem at all, and we could have shipped on the original schedule with more than acceptably-low defects, and perhaps even gotten some re-orders.

But Bose does things the right way. This was a great example.

boseguy

[soundminded]

boseguy

I think two things initially interested me about Bose 901. The first was the fact that it produced sound which for the first and only time in my experience escaped from the box it was coming from. I think whatever success this product enjoyed on the market came in large part from this fact. This brings me to the second reason and that was Dr. Bose's white paper. I must have read it at least 15 or 20 times. When a professor of electrical engineering and acoustics from MIT writes a paper on a subject I'm interested in, I sit up and take notice. Only a fool would offhandedly dismiss data, observations, conclusions from such a source.

Experience has led me to the conclusion that when correctly implimented, the direct/reflecting principle is overwhlmingly superior to the direct firing loudspaeker design. I felt Dr. Bose hadn't pursued it far enough. I would say that exploited to its full potential, it is not possible for audiophiles to set it up properly themselves. The integration of the speaker into the room is too complicated and optimally should be done with the aid of measuring equipment. Even after that is done, for accurate reproduction of acoustical instruments to satisfy very critical listeners as I feel I have become, the system has to be further tweaked to each individual recording, the variables in the way recordings are made being enormous. Ultimately, in most situations this can at present be done only by memory of what the instruments to be reproduced actually sound like or barring that, what similar instruments sound like. This requires at this point strong familiarity with the real thing. Even so, it's usually a long painstaking iterative process that can take weeks or even months for a single recording.

Thirty years after I invented my as yet unpublished general mathematical model related to acoustics and fifteen years after I first applied it to re-engineering loudspeakers I decided to tackle Bose 901. By then I had pretty much figured out genarally what I thought was wrong with it. It took about three years to impliment my solution which solved 4 critical issues. Interestingly money was not a factor. It cost less than $100 not counting equipment I already had around. It is of course impossible for anyone posting or reading on the internet to actually hear what other people have done so one person's superlatives are no more credible than another's. By itself, Bose 901 can be modified to reproduce acoustical instruments as they would be heard in the listener's room. But what they cannot do is reproduce a the sound of a symphony orchestra or any other instrument or ensemble of voices or instruments as they would be heard at a concert hall or other large live venue. That signal is not on recordings and no single pair of loudspeakers could reproduce it to achieve the required sound fields if it were.

I intend to continue experimenting with direct/reflecting speakers of different design but I'm not sure how much further I can get given the results I've already obtained with Bose 901. I'm surprised I got as far as I already did. Nearly 40 years on and I still get great enjoyment from them. Expensive initially but I'd say I got more than my money's worth out of them. Here's an interesting link.

http://www.crunchgear.com/2007/09/19/dr-bo...specs-and-more/

[Guest boseguy]

Of course, the 901 was not the Bose Corporation's first product. It was their first successful product, but not their first product.

In the mid-60's, they introduced the 2201, a 1/4-spherical floorstanding speaker designed to go in the corner. It was a self-powered speaker with 22 full-range drivers. There was one on display in the foyer of the "Mountain" building, and all the employees would pass by it every morning.

No one ever talked about it, and you could "feel" that it wasn't polite to ask too much about it. Given that, I was always puzzled as to why it was even on display.

I've attached the 2201 Owner's manual, and I hope the attachment comes through.

boseguy

[Guest boseguy]

OK, what's the trick to attaching a file?

I hit 'browse', then 'UPLOAD', I get the spinning arrow, the green elements in the status bar fill up, but nothing attaches.

What's the correct procedure?

boseguy

[soundminded]

I heard and saw that speaker at Audio Exchange on Hillside Avenue in Queens NY. Interesting but I was not impressed. It was a 1/8 sphere, the theory being it would simulate a spherical speaker when placed in the cornor of a room on the floor or ceiling which was supposed to be the ideal speaker design. I also saw a reflecting or a direct/reflecting console type stereo system at the Broadcaster's inn at WTFM on Horace Harding Boulevard near Utopia Parkway during the early 60s. I later wondered if Dr. Bose had anything to do with that design. I assume he didn't.

[tysontom]

OK, what's the trick to attaching a file?

I hit 'browse', then 'UPLOAD', I get the spinning arrow, the green elements in the status bar fill up, but nothing attaches.

What's the correct procedure?

boseguy

Dear boseguy:

First of all, welcome to the forum! It's good to have your expertise.

To upload an attachment, you must: 1) make sure the file is an acceptable file type, such as JPEG or PDF, and 2) be certain that the file is not too large. It must be less than 2MB in size, or it will not fly.

--Tom Tyson

[tysontom]

BTW, in case I left any doubt, the original Bose 901 and Series II are capable of enormous deep bass within their power handling capacity. They each have in aggregate the area of a 15" woofer but their maximum excursion is probably only about 3 mm. This means to equal the output loudness capability of an AR9 for deep bass, several pairs would have to be stacked. Measurements made by Hirsch-Hauk Labs when they first came out showed that at high volume they would respond down to 26 hz and at lower volume to 23 hz. They have about 10% THD, about twice an AR 12" woofer but it's still inaudible. But to equalize the system to be flat at those frequencies the power requirements are staggering. To achieve the same output at 30 hz you'd get with one watt at 1 khz where there are fairly efficient would I think take about 600 watts or more due to an added 10 db of boost. The rated system capacity is only 270 continuous so it would take several stacked to play deep bass loud. Playing deep bass, it eats up my available 138 wpc easily so some recordings require engaging the 10db shelved cut below 40 hz.

Soundminded,

I took a message you left from another post and copied it over to this string because we have been commenting on the performance of the 901 and 901 Series II. Therefore, I have some additional comments, based on information from the original patent, published documents from Bose and Hirsch-Houck Labs and other tests.

Harmonic Distortion:

When H&H Labs tested the 901, the distortion was actually 7% at 20 Hz, at the standard 1-watt input level. I believe the AR-3a had around 4-5% at a 1-watt that input level; however, Hirsch tested the AR-3a (ceramic woofer) at 10-watts input at 20 Hz with 9% harmonic distortion. Hirsch tested the AR-3 (Alnico woofer) seven years earlier with 20-watts input at 20 Hz with 8% distortion. Therefore:

• Bose 901 7% at 20 Hz with 1-watt input

• AR-3 8% at 20 Hz with 20-watts input

• AR-3a 9% at 20 Hz with 10-watts input

The real difference here is efficiency. Although heavily equalized below 200 Hz (maximum gain of 18 dB at 35 hz), I believe the 901, though inefficient, had slightly higher system efficiency (measured at 1000 Hz) than either the AR-3 or AR-3a, so 1-watt input into the 901 might give a higher acoustic-output level than 1 watt into either of the AR-3 or AR-3a. Note, also, that at 20 Hz both the AR-3 and the AR-3a are about 12 dB down in output. Hirsch also had difficulty in measuring the distortion in the 901, and with slight changes in microphone position, results varied. In any event, the distortion in either the Bose 901 or the AR 12-inch woofer is inaudible on most musical-input signals.

Driver specifications:

The drivers used in the original 901 and the 901 Series II were the CTS 4C1077, 4-inch 8-ohm long-excursion drivers mounted in a series/parallel configuration. I believe that other vendors might have been used. These drivers were a version of CTS’s standard 4-inch driver (4½-inch mounting flange), but these speakers had a longer voice coil and higher power-handling capacity (30-watts per speaker vs. 20 for the standard CTS driver). In the 901, Bose wired these 8-ohm drivers by series-wiring one set of three drivers on the back for 24 ohms, another three on the back in series for another 24 ohms and two on the back and the one on the front for another 24 ohms. These sets were then wired in parallel for 8-ohms total impedance. The maximum excursion on these 4-inch woofers was stated as "± ¼ inches" (± 6.25 mm), about twice what you thought it might be.

Bose 901 Sound Quality:

One of the hallmarks of the 901 was the clarity of the speaker. This is probably the thing that stands out almost as much as the spaciousness and three-dimensionality of the speaker. With no crossover, there are virtually no phase problems, but the electronic equalizer offsets any phase problems and also brings up the low frequency as well as the high frequency. Another important aspect of the 901 design was the use of non-parallel baffles (no speaker-mounted baffles were parallel to one another) internal to the speaker to minimize internal resonances. The speaker was a sealed design and contained a certain amount of fiberglass, but it was not called an “acoustic-suspension” design. The enclosure was sealed and an "acoustically-coupled design," The use of nine individual drivers mounted in different positions within the cabinet also offset the resonance problem better than using a single driver. Together, these factors make an audible difference in eliminating resonances, which can cause muddiness and coloration.

Power-Handling Capability:

Power-handling capability of the 901 and the 901 Series II is stated as:

• Continuous sine-wave power at any frequency: 50 watts (rms)

• Minimum recommended amplifier power: 25 watts-per-channel into 8 ohms

• Peak power handling ability (less than five seconds): 400 watts

• Maximum recommended amplifier for speech and music: 270 watts into 8 ohms.

Sources:

Bose 901 and Bose Series II Owner’s Manuals

Bose Patent No. 3,582,553

Bose New Bose Loudspeaker System Combines…

CTS of Paducah, Inc. commercial-loudspeaker catalog, 1973

HiFi Stereo Review Hirsch-Houck 1968 Review Bose 901

HiFi Stereo Review Hirsch-Houck 1967 Review Acoustic Research AR-3a

High Fidelity Magazine, Hirsch-Houck Labs, 1960 Review Acoustic Research AR-3

--Tom Tyson

[Guest boseguy]

The 2201 manual is 2.056MB PDF, so I guess that 2MB limit is pretty strict. Zipping it compresses it 0%, so unfortunately, it's no go.

When I was at Bose, we removed the "Maximum Power Handling" spec from the 901 altogether, as a marketing move. We thought it'd be very strong to be able to tell people that there was no max power restriction. I don't know if Bose has reinstated the max power limit (I haven't checked their site), and if they have, when they did so.

boseguy

[Robert_S]

The 2201 manual is 2.056MB PDF, so I guess that 2MB limit is pretty strict. Zipping it compresses it 0%, so unfortunately, it's no go.

The Bose 2201 Owner's Guide can be accessed directly from the Bose website:

http://products.bose.com/pdf/customer_serv.../2201_guide.pdf

Also available "An extensive list . . . including guides for discontinued products":

http://www.bose.com/customer_service/owner...eo_speakers.jsp

Robert_S

[soundminded]

Soundminded,

I took a message you left from another post and copied it over to this string because we have been commenting on the performance of the 901 and 901 Series II. Therefore, I have some additional comments, based on information from the original patent, published documents from Bose and Hirsch-Houck Labs and other tests.

Harmonic Distortion:

When H&H Labs tested the 901, the distortion was actually 7% at 20 Hz, at the standard 1-watt input level. I believe the AR-3a had around 4-5% at a 1-watt that input level; however, Hirsch tested the AR-3a (ceramic woofer) at 10-watts input at 20 Hz with 9% harmonic distortion. Hirsch tested the AR-3 (Alnico woofer) seven years earlier with 20-watts input at 20 Hz with 8% distortion. Therefore:

• Bose 901 7% at 20 Hz with 1-watt input

• AR-3 8% at 20 Hz with 20-watts input

• AR-3a 9% at 20 Hz with 10-watts input

The real difference here is efficiency. Although heavily equalized below 200 Hz (maximum gain of 18 dB at 35 hz), I believe the 901, though inefficient, had slightly higher system efficiency (measured at 1000 Hz) than either the AR-3 or AR-3a, so 1-watt input into the 901 might give a higher acoustic-output level than 1 watt into either of the AR-3 or AR-3a. Note, also, that at 20 Hz both the AR-3 and the AR-3a are about 12 dB down in output. Hirsch also had difficulty in measuring the distortion in the 901, and with slight changes in microphone position, results varied. In any event, the distortion in either the Bose 901 or the AR 12-inch woofer is inaudible on most musical-input signals.

Driver specifications:

The drivers used in the original 901 and the 901 Series II were the CTS 4C1077, 4-inch 8-ohm long-excursion drivers mounted in a series/parallel configuration. I believe that other vendors might have been used. These drivers were a version of CTS’s standard 4-inch driver (4½-inch mounting flange), but these speakers had a longer voice coil and higher power-handling capacity (30-watts per speaker vs. 20 for the standard CTS driver). In the 901, Bose wired these 8-ohm drivers by series-wiring one set of three drivers on the back for 24 ohms, another three on the back in series for another 24 ohms and two on the back and the one on the front for another 24 ohms. These sets were then wired in parallel for 8-ohms total impedance. The maximum excursion on these 4-inch woofers was stated as "± ¼ inches" (± 6.25 mm), about twice what you thought it might be.

Bose 901 Sound Quality:

One of the hallmarks of the 901 was the clarity of the speaker. This is probably the thing that stands out almost as much as the spaciousness and three-dimensionality of the speaker. With no crossover, there are virtually no phase problems, but the electronic equalizer offsets any phase problems and also brings up the low frequency as well as the high frequency. Another important aspect of the 901 design was the use of non-parallel baffles (no speaker-mounted baffles were parallel to one another) internal to the speaker to minimize internal resonances. The speaker was a sealed design and contained a certain amount of fiberglass, but it was not called an “acoustic-suspension” design. The enclosure was sealed and an "acoustically-coupled design," The use of nine individual drivers mounted in different positions within the cabinet also offset the resonance problem better than using a single driver. Together, these factors make an audible difference in eliminating resonances, which can cause muddiness and coloration.

Power-Handling Capability:

Power-handling capability of the 901 and the 901 Series II is stated as:

• Continuous sine-wave power at any frequency: 50 watts (rms)

• Minimum recommended amplifier power: 25 watts-per-channel into 8 ohms

• Peak power handling ability (less than five seconds): 400 watts

• Maximum recommended amplifier for speech and music: 270 watts into 8 ohms.

Sources:

Bose 901 and Bose Series II Owner’s Manuals

Bose Patent No. 3,582,553

Bose New Bose Loudspeaker System Combines…

CTS of Paducah, Inc. commercial-loudspeaker catalog, 1973

HiFi Stereo Review Hirsch-Houck 1968 Review Bose 901

HiFi Stereo Review Hirsch-Houck 1967 Review Acoustic Research AR-3a

High Fidelity Magazine, Hirsch-Houck Labs, 1960 Review Acoustic Research AR-3

--Tom Tyson

There were many other innovations in this deceptively simple seeming design. Most speaker designers try to move the resonance frequency down. Bose moved it up above 180 hertz where he felt the phase shift associated with resonance becomes inaudible. Then he uses an equalizer to compensate for the linear falloff below resonance. The use of nine drivers opearting over the same frequency range results in the contribution of minor resonances characteristic of each individual driver cancelled out due to the preponderence of the other drivers. Therefore he only has to concern himself with the overall average curve. Also, the construction of the cabinet in such a way that the drivers are not on baffleboards parallel to other cabinet walls eliminates internal standing waves.

The goal of my project was to flatten and extend the frequency response of the system. This means taking everything into account, the speakers, the room, the recording, everything. This is very hard to do even though to a casual observer it looks deceptively simple. The issue of FR of acoustic fields is much more complex than of electrical signals. However, when properly done, I feel the results are well worth the effort. Even without the addition of the acoustics of venue, on many recordings a joy to listen to and very different from other speakers I've heard.

[Carlspeak]

".......The goal of my project was to flatten and extend the frequency response of the system. This means taking everything into account, the speakers, the room, the recording, everything. This is very hard to do even though to a casual observer it looks deceptively simple. The issue of FR of acoustic fields is much more complex than of electrical signals. However, when properly done, I feel the results are well worth the effort. Even without the addition of the acoustics of venue, on many recordings a joy to listen to and very different from other speakers I've heard.

For an in depth discussion of what Soundminded is referring to above, visit the link below. Over 300 posts and 19,000 views makes it a popular thread. The link will bring you to the DIY loudspeaker forum. I suspect there are a lot of 'experts' there who gave their 2 cents worth on the subject. Who knows, maybe some of them really are experts. However, a thorough read of the posts should enlighten the curious somewhat about the complexities of the loudspeaker/room acoustic fields.

http://www.diyaudio.com/forums/forumdispla...mp;pagenumber=6

[soundminded]

For an in depth discussion of what Soundminded is referring to above, visit the link below. Over 300 posts and 19,000 views makes it a popular thread. The link will bring you to the DIY loudspeaker forum. I suspect there are a lot of 'experts' there who gave their 2 cents worth on the subject. Who knows, maybe some of them really are experts. However, a thorough read of the posts should enlighten the curious somewhat about the complexities of the loudspeaker/room acoustic fields.

http://www.diyaudio.com/forums/forumdispla...mp;pagenumber=6

If you try to build a high fidelity music reproducing system, unless you are haphazardly assembling parts by random chance, you are working to a mathematical model whether you know it or not. Even just copying somenoe elses design or trying to better it, works to a model. One of the few really clever ideas I've had in life was my model. It came to me totally unexpectedly about 35 years ago and I've been playing with it ever since. I've had a lot of fun with it but no profit from it as yet. Unfortunately such models are not patentable but best protected as trade secrets. That is why Bill Gates will never really open the box to let you see what's inside. That's the crux of where he makes his money from and if he did, he'd be ruined. It's one thing to develop a model, another to impliment it. It can be extremely frustrating. No instrument exists to test my model but I've designed one. There should be good correlation between what is tested and what is heard using it. Perhaps when I die, I'll bequeath it or maybe it will die with me. It can get very frustrating and I nearly gave up with Bose 901 as unfixable more than once. But my school had the same motto as Kansas, "per aspera ad astra" which means through hardship to the stars. Once the adjustments were "tuned" to the room, the hardest part, I've had to make further adjustments to accomodate the variables of each recording. Getting one right can take months and dozens of iterative EQ trials. Somehow when you get it right, you just know it. It sounds right. Audio experts tell us that auditory memory is very short but I'm not so certain that is necessarily true. You hear the voice of someone you haven't spoken with in years and it is recognizable instantly. There is a slight change in timbre of a voice you know and you can tell even over a phone, it sounds like you're coming down with a cold. Even the slight distortion is recognizable from the norm instantly. Or you speak with someone for the first time who sounds like they have a cold and you find out they've had a lifelong sinus condition. Listening to actual unamplified musical instruments frequenty helps a lot. Then they tell you to go out and pick out audio equipment that sounds closest to you to real music. And you can't becaue none of them do. It's a painful truth they never even considered. I heard AR3 sound like live music...twice.

[Carlspeak]

I didn't test my link until today and found it takes you to the diy speaker home page - not to the specific thread I had originally captured and pasted.

For those interested, the thread is "LOUDSPEAKERS AND ROOM AS A SYSTEM".

Enjoy!

[Guest tony3d]

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