[Roger A. Modjeski]

This is the intro lecture, the technical stuff starts around 40 minutes. There are a series of these. Excellent stuff at a fraction of the price of going to MIT. The speaking part alone is worth listening to if you want to be doing something else.

At 43:40 he speaks to folklore in Hi Fi and the magazines

http://teachingexcellence.mit.edu/inspiring-teachers/amar-bose-6-312-lecture-01-introduction

[geowak]

I have thought for many years that Dr Bose was a brilliant engineer. Some people do not give his designs the credit they deserve. He was a pioneer and his designs are inspiring. There are many people who don't know he also invented a sophisticated suspension system for automobiles. Really better than what exists on todays vehicles, as far as effective suspension works. I have been a fan of him for over 30 years and owned his 901 speakers for about 15 years.

[Roger A. Modjeski]

I found the 40 minute introduction most interesting and I learned a few things. He was careful to lay out the rules, discourage students who are in there for the wrong reasons or may drop out, and said some interesting things about the value of this course in their unknown future. I am quite impressed with him as a teacher.

He points out some interesting things about the range of sound and lumped parameter systems. He puts a lot of emphasis on math, more than I would. I think the practical application of math comes hard to college students who may find it easier as the years go by. It was my experience in college that math was almost everything and getting a intuitive hold on the subject was barely mentioned. In my teaching method I reverse that making the intuitive approach more important and adding the math later when the student has a better grasp of the big picture. I can tell you how a dynamic driver works using your practical knowledge about the world around you or I can do it with calculus and nothing else. The calculus version doesn't go over so well.

I had an interesting experience with a student the other day. He had proven by calculus that maximum power transfer occurs when the load is matched to the source impedance. This is also being discussed in audio forums. His proof was correct and perhaps because of it he assumed that we match loads in all electrical situations. However in more cases than not we actually mismatch the load by a large margin. For instance in our electrical power system the load is often 20 or 100 or 1000 times the source impedance. The only case that comes to mind of matched loads is in the TV Cable system, Telephone system,  RF transmission systems and our Ethernet systems. These however are few compared to the number of systems where impedances are not matched.

When it comes to amps, preamps and speakers none of those are impedance matched systems. There are a lot of questions about "matching" a preamp to a power amp. In that case were are actually discussing the impedance "mismatching" where we want the preamp to have much lower output impedance than the power amp input impedance. That is exactly what is happening in our home electrical system. We are indeed mismatched.

I pointed out to this student that when source and load impedances are matched we also lose half the power into heat and assured him the electric company was not doing that. They are doing everything they can to provide a low source impedance to our homes.

[bdp24]

     I really enjoyed Dr. Bose's talk, and found him very likeable. Intellectually honest and humble, too. But.....the main thought that comes to mind is, that with all of his knowledge and abilities, something was terribly wrong went he applied it to the design of loudspeakers. I don't want to argue that point---everyone is entitled to their opinion of his designs.
     I had been bitten with the Hi-Fi bug when I heard the system my best friend (if you like instrumental Rock n' Roll, check out the Combo he's playing Bass in these days, Los Straitjackets) had put together after he moved away from San Jose to Santa Cruz (SC didn't have a dress code!) for our Senior year in High School. It was a Rek-O-Kut Transcription Turntable and Arm (acquired from a radio station) with one of the Shure Cartridges (of course---it was 1968!), an H.H. Scott Integrated Amp and a pair of their 2-way loudspeakers. It sounded WAY better than my parents Magnavox Console! So I was off, chasing down my own Stereo. Working part-time while going to College made saving $500 for a pair of really good speakers (the cost of a pair of AR 3A's or Rectilinear 3's in 1970) take quite a while. By the time I had the dough, the Bose 901 had been introduced to near unanimous raves (J. Gordon Holt in Stereophile being the lone dissenting vote), and Pacific Stereo had it to listen to in their 'Best" room. The 901's made the AR's sound dark, small, and closed-in---the opposite of open. What else was there? My band had a set of the huge JBL Voice-Of-The-Theatre PA speakers, so when I listened to their Century L-100 speakers I heard them for what they were---very colored and "shouty" (as the Brit's like to say). Nasty little buggers, they were. Plus, orange foam grilles ? So 901's it was.
     The honeymoon didn't last long. It was not entirely their fault, for I heard my first Electrostatic Tweeter---the RTR. ESS (pre-Heil driver) used three of them in their $1200/pr Transtatic I, along with the great KEF B139 Woofer and 5" Bextrene Mid-Range driver. Now THIS was a speaker! Transmission-line loading of the B139 and Mid-Range cone, RTR's firing front and rear. But $1200?! That wasn't fair to the $500/pr 901. Or was it? Bose claimed the 901's "11% direct/89% reflected" sound was "correct" because that's what one hears live in a Concert Hall. SO WHAT?! That direct/reflected sound is already encoded in the recordings made in Halls. To then reproduce that sound via the BOSE 901's 11%/89% design is to compound the effect. Besides, what has that to do with reproducing Pop Music studio recordings, which is what I mostly listened to at the time? But even more than that, where were the delicate high-frequencies? Cymbals through the 901's didn't sound like my Zildjians, nor any I had ever heard. I'm sure Bose's research revealed the fact that the walls, seats, audience, and size of the Concert Halls attenuated high frequencies. SO WHAT?! The 901 had no woofer, no tweeter, and sounded like it. A big, cloudy, amorphous blob of sound. No detail, no imaging, ridiculously overblown voice and instrument sizes, very non-transparent, and downright annoying. A deeply flawed design (it seems surprisingly like that of a proponent of, say, tweeky capacitors, who takes what makes a cap good in one application and generalizes it to other, inappropriate applications. Roger has been talking about this very subject lately) from a very knowledgeable man, but a very poor loudspeaker designer. Sorry . My inexperienced ears just needed a little educating. And that they got when I heard the Quad ESL, in 1972. Uh, wow. Let's assume Dr. Bose knew more than Peter Walker about a lot of things (I don't know that to be the case, but which of them did we just watch teach a class at MIT?). Now I ask you---who made, by far, the better Loudspeaker? After hearing the Quad, NO cone speaker cut it for me, Bose or otherwise. I remember the Dr. saying, when questioned about it in light of the new Heil driver, that the means of propagating sound doesn't matter (ESL vs. Dynamic Cone vs. Heil, etc.). Sorry, that is absolutely untrue, Amar, and OBVIOUSLY so. You don't need no P.H.D. to know that, either. I ask this half in jest here, considering , but what was that album title in the techno era by that little dipshit Thomas Dolby? Oh yeah, "Blinded By Science"

[a.wayne]

That about sums it up , now less assume that Peter walker knew more about building a better speaker than Bose, which one was more successful at it , quad vs Bose...

Survey says Bose ....

[Photon46]

That about sums it up , now less assume that Peter walker knew more about building a better speaker than Bose, which one was more successful at it , quad vs Bose...

Survey says Bose ....

Well, by that logic the Toyota Corolla is a better auto than a BMW 3 series and Beyonce trumps pretty much everyone else.

[a.wayne]

Correct,

The toyota corolla is better transportation than an M3 , it is to more people and records are produced  for sales bad records are the ones not selling, those are the metrics by which they are judged,so less keep it tight ...



Bose is successful by any measure, many derive pleasure from their products, laughing at Bose because your preference is Quad is ironic ,  many find the ESL 57 low playing, no bass, no treble,  arch city speakers , not much  different from  those laughing at Bose owners, i find it best to be  audio agnostic when it comes to hi-fi  to each his own, too much silly arguments over analog, digital, toobs , sand et al ....


No, No  and yes , ribbons are my current preference.....

[bdp24]

I'm not laughing at Bose, or Bose owners. Hey, I was a Bose owner! My intended point was a quite different one. To argue that the product which sells in greater numbers is the "better" is an old tact, and I'm genuinely surprised to see it in a Music Reference discussion. Are you here accidently? I'm currently driving a Toyota (though I don't own it), and I can tell you that my old '83 BMW 528e was, of course, a way, Way, WAY better car than the Toyota. I got 240,000 miles and 25 years out of it, too. You cannot be serious dude !

[a.wayne]

Never a Bose owner , but i do respect their success and my neighbor in the early to mid 70's had an 901 with the  Bose power amp that i did thoroughly enjoy at the time, of course R&B and Disco it was ...

[Roger A. Modjeski]

I posted the link for the information the lectures provide. Whether we like the product is not the issue and I would like us to refrain from discussing the speaker. Perhaps Dr. Bose is an example of too much scientific theory and not enough listening, however I believe the technical information concerning sound is correct. We perhaps have to forgive the way the company went about marketing. I am not recommending their products

I had no idea that he started the company in 1964, several years before the 901. I have read his AES paper on direct vs reflected sound. Like many engineers he got hooked on that feature to the detriment of looking at other things. Walker, with the help of Baxandall created a fine speaker in the QUAD 57 largely because his choice to make and electrostatic. Beveridge did one better in my opinion by choosing ESL and asking a second question "How best does one illuminate a room with sound".

For those who can sit through the lectures there may be some valuable tidbits of information on how sound propagates, the broad range of wavelengths, and other fundamental laws on the behavior of sound. His comparison to wavelength range of sound to frequency range of amplifiers I found interesting. I expect to learn a thing or two.

I find it curious that many audiophiles have no idea what a wavelength is at various frequencies, or the basic principles of a closed box vs ported box vs open baffle speaker. When I discuss speakers with both speaker builders and laymen I am often shocked at the lack of knowledge.

Please do what you can to separate the company from the teacher. From what I heard, most of the Bose products were designed by his graduate students, not him! 

[smargo]

I  We perhaps have to forgive the way the company went about marketing. I am not recommending their products

what do you have to forgive them for - we all market our products - i think bose has marketed their products incredibly over the years - to me they have brilliant people in their marteing department

just goes to show you - you dont have to have the best product - only a perception that you have the best product

[Roger A. Modjeski]

In lecture #2 at 12:15 Dr Bose mentioned a favorite historic note of mine. Lord Rayleigh studied the properties of sound and published his results in 1877 when we had no speakers. I have read these papers where he describes the behavior of a 1 inch piston in an infinite baffle. I wish more speaker designers would give Rayleigh's work a look. Those Brits were sure good at basic science. A more modern contributor to our age from that country is Peter Baxandall.

http://www.nobelprize.org/nobel_prizes/physics/laureates/1904/strutt-bio.html

[kenkirk]

I had a set of Bose 301's in college back in the 70's. One night with the lights off and Zeppelin cranked I noticed light beating to John's drums through the speakers port. I was amazed. Bose had used a light bulb of some sort to absorb excess energy to save the tweeter. We loved it. So when asked how the evening went, I would respond we were lighting up the 301's last night! 

Today I have a Bose Sound Link bluetooth speaker that I use almost daily to stream Radio Paradise from my Ipad. I love that speaker. But other than that, no more Bose for me. " No highs, no lows, must be Bose" 

Ken

[Russell Dawkins]

I had a set of Bose 301's in college back in the 70's. One night with the lights off and Zeppelin cranked I noticed light beating to John's drums through the speakers port. I was amazed. Bose had used a light bulb of some sort to absorb excess energy to save the tweeter.

The light bulb as compressor/fuse is an old trick. I have seen it used by Tannoy in one of their not-so-cheap small PA speakers and JBL, I believe, did too (or was it Fender?). I'm pleased to say I conceived of this before I discovered it in use by various manufacturers and was surprised to see it had already been thought of.

[FireGuy]

just goes to show you - you dont have to have the best product - only a perception that you have the best product


So much truth in this statement.  My all time favorite business (marketing) quote comes from Henry Ford:

"If I had asked my customers what they wanted they would have said a faster horse."

[Roger A. Modjeski]

The light bulb as compressor/fuse is an old trick. I have seen it used by Tannoy in one of their not-so-cheap small PA speakers and JBL, I believe, did too (or was it Fender?). I'm pleased to say I conceived of this before I discovered it in use by various manufacturers and was surprised to see it had already been thought of.

The light bulb is very clever and takes advantage of the fact that a hot filament is about 10 times higher resistance than a cold filament. As Russell suggests it does compress, it does save the tweeter and act as a fuse if really high power is applied to the speaker. I had not considered its value as a light show. In college I had a color organ with 4 channels and a 2x3 foot light box to view. It was a big hit. I built is from scratch and it had accessory outlets of 1000 watts each which served well for light dimmers and heat control for my pop-corn popper which also served as a soup heater.

Bose is a clever and successful company. Its too bad they don't aim a bit of their resources toward the High End customer.  At one point they were second in sales only to Radio Shack which was #1 in the 1990s. Now I would expect they have been #1 for a long time though I have not been able to find a list of the top ten. Does anyone know a link to such a list?

[Ericus Rex]

As I read this post and scroll down to the bottom, I find an ad for the Bose Soundtouch at the bottom of the screen.  Coincidence?