Dr. Bose Model of the "Discipline of Acoustics"

[Rmar]

I recently watched several of Dr. Bose's lectures online through MIT. While the math is well beyond anything I have experienced, I tried to stay focused on the meaning behind it.

In the video below, starting at 38:00 and going to about 45:00, Dr. Bose introduces his students to a model for what I will call “audio enjoyment experience." Dr. Bose referred to it as the “…discipline of acoustics.” He suggests there are three domains, or what he calls "sets” in the model: 1 - Device Set, 2 - Measurement Set and 3: Perception Set. Other than offering a few personal comments clearly out of academic frustration for the industry and marketplace for Hi-Fi, he gave no more details about his model and moved on to other topics. Yet, as I looked at his model, a few questions came to mind, which admittedly could never be answered with absolute certainty. Just the same though, a question is a question. The one that I had was this:

Given the three sets, to what extent does each domain contribute to a person’s audio enjoyment experience? Is it the equipment, the measurements, or our perception and/or by how much of each?

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

In hindsight, knowing that the lecture he gave in the video was to pique the interest of his students in the course material to come, I can also say it did the same me. What I can also say is that I would not have lasted another hour in his class given the glimpse of the level of mathematics they were about to get involved in. I am certain about that.

 

[IAtaman]

Interesting video. When was this recorded?

 

[Rmar]

Recorded in 1995. There are a dozen or so video's open sourced on the MIT web-site. Interesting to watch.

Amar G. Bose: 6.312 Lecture 02—Wave Equations | Teaching Excellence at MIT

Topics include: one-dimensional wave equations; vector wave equations; their derivations; creative development processes to reach established results; comments on feature film "Stand and Deliver". Rec

teachingexcellence.mit.edu

Below are some thoughts about audio history and Bose, if I dare.

It is not at all hard to imagine that Dr. Bose and his “901” will very likely be remembered as one of the most forward-looking if not one of the most industry-disrupting speaker designs of the 20th century. Oddly shaped, full-range drivers (and many multiples of them); wave guides in the cabinet; room coupling design intent; rear porting; and yes…the piece de resistance of haters– that external EQ to electronically manipulate the drivers. Each of these features individually were significant. All of them in the same speaker? Heresy! Fast forward 50 years and these same features are becoming commonplace, as their virtues are discovered.

As time goes by, as audio “groupthink” wanes, future audio enthusiasts will wonder what all the fuss was about. The will see the Bose 901 for what it was – a catalyst for new ways of thinking and designing. There is a piece of the “901” in almost every speaker on the market today. We have all benefited from Dr. Bose’s 901 creation in one way or another no matter what our favorite speakers are are.

Amar G. Bose: 6.312 Lecture 02—Wave Equations | Teaching Excellence at MIT

Topics include: one-dimensional wave equations; vector wave equations; their derivations; creative development processes to reach established results; comments on feature film "Stand and Deliver". Rec

teachingexcellence.mit.edu

 

[Rmar]

Interesting video. When was this recorded?

1995

 

[Spkrdctr]

Given the three sets, to what extent does each domain contribute to a person’s audio enjoyment experience? Is it the equipment, the measurements, or our perception and/or by how much of each?

Thousands and thousands of pages have been written on this topic. If you get it quantified and nailed down across the board, let me know. It really is a serious but VERY hard question to answer. You got me thinking!

 

[GXAlan]

There was a new-old-stock Bose 901 that was around locally so I decided to pick it up and to say that my jaw dropped is an understatement. They are one of the best speakers I have had for the size once set up properly. It really makes me wonder what a modern cost-no-object interpretation would look like.

“Given the three sets, to what extent does each domain contribute to a person’s audio enjoyment experience? Is it the equipment, the measurements, or our perception and/or by how much of each?”

I think the answer is not clear because it’s different for each person.

1) Equipment
For me, ergonomics is very important. I have made comments about the enjoyment I had with the metal remote control of my Marantz PM-10/SA-10 combo. Along the same category, how would you feel about a product made in your hometown versus somewhere else? Location of manufacture is part of the enjoyment.

2) Measurements
They are important in the same way we appreciate the engineering of a very fast car. I like that my Meyer Sound Amie 900W of peak power even though I listen at reasonable numbers. Seeing lower phase distortion and lower harmonic distortion is also good. That said, you don’t want to ignore a good sounding product because the measurements aren’t great. We talk about products that roll off at 18 or 19 kHz instead of being completely flat but not everyone can still hear to 18 kHz in the first place.

Dirac ART allows you to improve the integration of subs and your bed layer speakers, but if your full range speakers already get to 35 Hz or so, extended them down to 20 Hz doesn’t matter much (for movies) since there is very little content that lives there (as opposed to LFE).

3) Perception
This is the most important. It doesn’t mean that you ignore science, sighted bias, snake oil, etc. But the guy who thinks those fancy cables improved his sound probably does in fact experience joy when listening to his system…

 

[GXAlan]

You put lots of flesh on the model, GXAlan! All the more to think about. Love it.

I cannot emphasize enough how much a remote goes toward the enjoyment of a premium product.

The luxury automotive guys know this. They know that the way that the door closes, the character of the warning chimes, etc. all translate into consumers enjoying their luxury purchase.

Yet in audio, it seems that this is one area of frequent cost savings…

 

[Rmar]

I cannot emphasize enough how much a remote goes toward the enjoyment of a premium product.

The luxury automotive guys know this. They know that the way that the door closes, the character of the warning chimes, etc. all translate into consumers enjoying their luxury purchase.

Yet in audio, it seems that this is one area of frequent cost savings…

Another case where the end user/ customer isn't be heard/or asked.

 

[Rmar]

There was a new-old-stock Bose 901 that was around locally so I decided to pick it up and to say that my jaw dropped is an understatement. They are one of the best speakers I have had for the size once set up properly. It really makes me wonder what a modern cost-no-object interpretation would look like.

“Given the three sets, to what extent does each domain contribute to a person’s audio enjoyment experience? Is it the equipment, the measurements, or our perception and/or by how much of each?”

I think the answer is not clear because it’s different for each person.

1) Equipment
For me, ergonomics is very important. I have made comments about the enjoyment I had with the metal remote control of my Marantz PM-10/SA-10 combo. Along the same category, how would you feel about a product made in your hometown versus somewhere else? Location of manufacture is part of the enjoyment.

2) Measurements
They are important in the same way we appreciate the engineering of a very fast car. I like that my Meyer Sound Amie 900W of peak power even though I listen at reasonable numbers. Seeing lower phase distortion and lower harmonic distortion is also good. That said, you don’t want to ignore a good sounding product because the measurements aren’t great. We talk about products that roll off at 18 or 19 kHz instead of being completely flat but not everyone can still hear to 18 kHz in the first place.

Dirac ART allows you to improve the integration of subs and your bed layer speakers, but if your full range speakers already get to 35 Hz or so, extended them down to 20 Hz doesn’t matter much (for movies) since there is very little content that lives there (as opposed to LFE).

3) Perception
This is the most important. It doesn’t mean that you ignore science, sighted bias, snake oil, etc. But the guy who thinks those fancy cables improved his sound probably does in fact experience joy when listening to his system…

You put lots of flesh on the model, GXAlan! All the more to think about. Love it.

 

[Anton D]

There was a new-old-stock Bose 901 that was around locally so I decided to pick it up and to say that my jaw dropped is an understatement. They are one of the best speakers I have had for the size once set up properly. It really makes me wonder what a modern cost-no-object interpretation would look like.

“Given the three sets, to what extent does each domain contribute to a person’s audio enjoyment experience? Is it the equipment, the measurements, or our perception and/or by how much of each?”

I think the answer is not clear because it’s different for each person.

1) Equipment
For me, ergonomics is very important. I have made comments about the enjoyment I had with the metal remote control of my Marantz PM-10/SA-10 combo. Along the same category, how would you feel about a product made in your hometown versus somewhere else? Location of manufacture is part of the enjoyment.

2) Measurements
They are important in the same way we appreciate the engineering of a very fast car. I like that my Meyer Sound Amie 900W of peak power even though I listen at reasonable numbers. Seeing lower phase distortion and lower harmonic distortion is also good. That said, you don’t want to ignore a good sounding product because the measurements aren’t great. We talk about products that roll off at 18 or 19 kHz instead of being completely flat but not everyone can still hear to 18 kHz in the first place.

Dirac ART allows you to improve the integration of subs and your bed layer speakers, but if your full range speakers already get to 35 Hz or so, extended them down to 20 Hz doesn’t matter much (for movies) since there is very little content that lives there (as opposed to LFE).

3) Perception
This is the most important. It doesn’t mean that you ignore science, sighted bias, snake oil, etc. But the guy who thinks those fancy cables improved his sound probably does in fact experience joy when listening to his system…

Great post!

A lot of fun can be left behind if we aren’t attentive!

 

[Cbdb2]

When I heard the 901s 30 years ago I was totally unimpressed. And expensive. Ild like to see measurements.
What wave guide?
And why is an EQ necessary? Usually bad freq. response.

 

[GXAlan]

When I heard the 901s 30 years ago I was totally unimpressed. And expensive. Ild like to see measurements.

In room.

What wave guide?

And why is an EQ necessary? Usually bad freq. response.

What about the JBL 708i or JBL M2? They need active EQ because the in-eq’d frequency response is bad…

The high frequencies do roll off on the Bose 901, although it’s not too different from a cinema curve.

I do agree that for music, it’s nice to add a super tweeter like the JBL UT405 to fill in the last octave.

What these measurements don’t show you is the *benefit* to in-room experience that you get.

 

[Cbdb2]

Which is totally room dependant. Why doesnt that spectrogram show the 15 dB boost in the low end? And that 30db drop! in the last octave doesn't match any realistic room curve.

 

[Rmar]

When I heard the 901s 30 years ago I was totally unimpressed. And expensive. Ild like to see measurements.
What wave guide?
And why is an EQ necessary? Usually bad freq. response.

Why is an EQ necessary? Same reason thousands of EQ's are sold every year and many millions more are in use. But there is a difference. The difference is Bose 901 EQ was specifically designed to work as a “system” with its corresponding speaker components. The cage, voice coil, spider, cone, dust cap, cabinet, room placement, and the EQ…all work as one system. The intentionality of the Bose EQ’s design is not lost on the loudspeaker measurement standards body. ANSI/CTA-2034A requires in the setup of speakers prior to testing, that they be set-up the way the manufacturer designed them. Period. ANSI’s position on speaker set-up also means that any test results published that did not have the EQ engaged are non-compliant. Non-compliant also means unprofessional. Results that are non-compliant are also misleading - intentionally or otherwise. Removing the EQ from the Bose 901 system for practical and testing purposes makes no legitimate point. It’s like measuring a 3-way speaker without its crossover. It’s nonsensical.

 

[GXAlan]

Which is totally room dependant. Why doesnt that spectrogram show the 15 dB boost in the low end? And that 30db drop! in the last octave doesn't match any realistic room curve.

The room measurement is mine with Series 6 drivers and EQ.

The directivity is from Erin Audio Corner on a Series 5 with a Klippel NFS.

The spectrogram is showing anechoic measurements. In room, you get a lot of room gain. This can be tuned of course because it's pretty easy to EQ

 

[Cbdb2]

You have 15 dB of room gain in the low end?

 

[GXAlan]

Removing the EQ from the Bose 901 system for practical and testing purposes makes no legitimate point. It’s like measuring a 3-way speaker without its crossover. It’s nonsensical.

In a way, it shows you the “no high, no lows, must be Bose” explanation. In the era of the 901, you can imagine recommendations to use the EQ being understood like needing “official” brand ink for printers. The labeling of tape loop/tape monitor, etc can be confusing as well, so people might simply have connected the 901 without the equalizer if they didn’t understand what we know today.

You have 15 dB of room gain in the low end?

There hasn’t been a NFS spin of the Bose Series 6 just Series 5. When Amir has some time, I will send him mine to measure.

That said, I have shown some in room data in the same room with three different versions.

Bose 901 Series VI Active Equalizer Measurements

Bose 901 Series VI Active Equalizer Measurements The Bose 901 Series V has been measured on the Klippel NFS. In Erin's measurements, he noted that the equalizer added an extreme level of distortion. I recently tried a Series VI in my own home and came around incredibly impressed with the...

www.audiosciencereview.com

Bose Model 901 Active Equalizer ('68 Edition) Measurements

Bose Model 901 Active Equalizer ('68 Edition) Measurements I was able to source an original Bose Model 901 Active Equalizer (Series One). While there is no serial number on the equalizer, it was part of a set that had one Bose Model 901 speaker with a serial number BELOW #800. The matching...

www.audiosciencereview.com

Bose 901 Series VI ver 2 ("Final Edition") Measurements and Review

Bose 901 Series VI ver 2 Active Equalizer (Final Edition) Measurements and Review Part 1: The Bose 901 Series VI: https://www.audiosciencereview.com/forum/index.php?threads/bose-901-series-vi-active-equalizer-measurements.44569/ Part 2: The Bose Model 901 '68 Edition...

www.audiosciencereview.com

The thing to note is that the PA version of the Bose 901, called the 802 (which only had 8 instead of 9 drivers) was rated for 1.2 kW of peak power handling per AES standards and nearly 1 kW under Bose’s more strict duty cycle testing.

https://assets.bose.com/content/dam/Bose_DAM/Web/pro/global/products/loudspeakers/Panaray_802_Series_IV/Downloads/Technical_datasheet/tds_Panaray_802_SeriesIV.pdf

The 2004 Japanese-market Bose 901, which is likely the U.S. Series VI ver 2 is rated at:

You don’t need a lot of power to enjoy the 901’s (it works with a 300B SET) but it is telling that the design handles more power than anything you would have imagined in its price range. Think about the amplifiers that give you a true 270W rms into 8 ohms!

 

[Rmar]

In a way, it shows you the “no high, no lows, must be Bose” explanation. In the era of the 901, you can imagine recommendations to use the EQ being understood like needing “official” brand ink for printers. The labeling of tape loop/tape monitor, etc can be confusing as well, so people might simply have connected the 901 without the equalizer if they didn’t understand what we know today.


There hasn’t been a NFS spin of the Bose Series 6 just Series 5. When Amir has some time, I will send him mine to measure.

That said, I have shown some in room data in the same room with three different versions.

Bose 901 Series VI Active Equalizer Measurements

Bose 901 Series VI Active Equalizer Measurements The Bose 901 Series V has been measured on the Klippel NFS. In Erin's measurements, he noted that the equalizer added an extreme level of distortion. I recently tried a Series VI in my own home and came around incredibly impressed with the...

www.audiosciencereview.com

Bose Model 901 Active Equalizer ('68 Edition) Measurements

Bose Model 901 Active Equalizer ('68 Edition) Measurements I was able to source an original Bose Model 901 Active Equalizer (Series One). While there is no serial number on the equalizer, it was part of a set that had one Bose Model 901 speaker with a serial number BELOW #800. The matching...

www.audiosciencereview.com

Bose 901 Series VI ver 2 ("Final Edition") Measurements and Review

Bose 901 Series VI ver 2 Active Equalizer (Final Edition) Measurements and Review Part 1: The Bose 901 Series VI: https://www.audiosciencereview.com/forum/index.php?threads/bose-901-series-vi-active-equalizer-measurements.44569/ Part 2: The Bose Model 901 '68 Edition...

www.audiosciencereview.com

The thing to note is that the PA version of the Bose 901, called the 802 (which only had 8 instead of 9 drivers) was rated for 1.2 kW of peak power handling per AES standards and nearly 1 kW under Bose’s more strict duty cycle testing.

https://assets.bose.com/content/dam/Bose_DAM/Web/pro/global/products/loudspeakers/Panaray_802_Series_IV/Downloads/Technical_datasheet/tds_Panaray_802_SeriesIV.pdf

The 2004 Japanese-market Bose 901, which is likely the U.S. Series VI ver 2 is rated at:
View attachment 343452

You don’t need a lot of power to enjoy the 901’s (it works with a 300B SET) but it is telling that the design handles more power than anything you would have imagined in its price range. Think about the amplifiers that give you a true 270W rms into 8 ohms!

In a way, it shows you the “no high, no lows, must be Bose” explanation. In the era of the 901, you can imagine recommendations to use the EQ being understood like needing “official” brand ink for printers. The labeling of tape loop/tape monitor, etc can be confusing as well, so people might simply have connected the 901 without the equalizer if they didn’t understand what we know today.


There hasn’t been a NFS spin of the Bose Series 6 just Series 5. When Amir has some time, I will send him mine to measure.

That said, I have shown some in room data in the same room with three different versions.

Bose 901 Series VI Active Equalizer Measurements

Bose 901 Series VI Active Equalizer Measurements The Bose 901 Series V has been measured on the Klippel NFS. In Erin's measurements, he noted that the equalizer added an extreme level of distortion. I recently tried a Series VI in my own home and came around incredibly impressed with the...

www.audiosciencereview.com

Bose Model 901 Active Equalizer ('68 Edition) Measurements

Bose Model 901 Active Equalizer ('68 Edition) Measurements I was able to source an original Bose Model 901 Active Equalizer (Series One). While there is no serial number on the equalizer, it was part of a set that had one Bose Model 901 speaker with a serial number BELOW #800. The matching...

www.audiosciencereview.com

Bose 901 Series VI ver 2 ("Final Edition") Measurements and Review

Bose 901 Series VI ver 2 Active Equalizer (Final Edition) Measurements and Review Part 1: The Bose 901 Series VI: https://www.audiosciencereview.com/forum/index.php?threads/bose-901-series-vi-active-equalizer-measurements.44569/ Part 2: The Bose Model 901 '68 Edition...

www.audiosciencereview.com

The thing to note is that the PA version of the Bose 901, called the 802 (which only had 8 instead of 9 drivers) was rated for 1.2 kW of peak power handling per AES standards and nearly 1 kW under Bose’s more strict duty cycle testing.

https://assets.bose.com/content/dam/Bose_DAM/Web/pro/global/products/loudspeakers/Panaray_802_Series_IV/Downloads/Technical_datasheet/tds_Panaray_802_SeriesIV.pdf

The 2004 Japanese-market Bose 901, which is likely the U.S. Series VI ver 2 is rated at:
View attachment 343452

You don’t need a lot of power to enjoy the 901’s (it works with a 300B SET) but it is telling that the design handles more power than anything you would have imagined in its price range. Think about the amplifiers that give you a true 270W rms into 8 ohms!

Yes, that is exactly what is happening. Removing the EQ during set-up leads to misleading results. It proves nothing and we end up with old wife’s tales like “…no highs, no lows, must be Bose.” That is exactly why the language is in the ANSI standard. ANSI understands how competitors use and misuse all sorts of methods of testing. Professional standards prevent companies from doing A-B tests with competitors’ equipment to discredit them. Could you imagine if back in the day, all Bose retailers removed the crossovers from competing speakers before A-B testing in sales demonstrations? Of course, all this is not to say that old wife’s tales are not helpful on some level. They are, but not in the way people might think. What is really going on is a soothing of an audiophile’s anxiety that they have made the right choices for themselves. The consumer level of audio offers a dizzying array of choices and combinations of equipment. No one is completely sure they have not overlooked something and that their choices today will be their desires tomorrow. It is the lack of certainty that feeds “audiophiliactic anxiety.” Just look at the amount of selling and buying churn that goes on each day on-line. Audiophiles eager to find the next best thing. Old wife’s tails help audiophiles relax and enjoy the music, even if they are searching the internet for something else while they are listening.

 

[Cbdb2]

This is the Bose I know:

And as far as the 901s I agree with the consumer report in 1981, that Bose tried to sue them over, that said "they make individual instruments sound gigantic and the sound tended to wander around the room". And they will sound very different in different rooms, 80% of the sound comes out the back. If I want that Ill turn my speakers backwards.

 

[GXAlan]

This is the Bose I know:

And as far as the 901s I agree with the consumer report in 1981, that Bose tried to sue them over, that said "they make individual instruments sound gigantic and the sound tended to wander around the room". And they will sound very different in different rooms, 80% of the sound comes out the back. If I want that I’ll turn my speakers backwards.

It would only work to turn it backwards if you have the oblique angles like the 901.

The details are much more interesting

https://www.supremecourt.gov/pdfs/transcripts/1983/82-1246_11-08-1983.pdf

“After careful consideration of Seligson's testimony and of his demeanor at trial, the Court finds that Seligson's testimony on this point is not credible.”

The problem was that Mr. Seligson was also trying to commercialize his own speaker at the time with its own patent so there was conflict of interest.

The other issue was that in the panel listening, the listeners were asked if the Bose 901 sounded close to their reference direct radiating speaker as opposed to asking which speaker they preferred.

Bose was asking Consumer Reports to clarify/retract Selinger’s statements, the magazine didn’t and they went to court.

Bose Corp. v. Consumers Union of United States, Inc., 508 F. Supp. 1249 | Casetext Search + Citator

Read Bose Corp. v. Consumers Union of United States, Inc., 508 F. Supp. 1249, see flags on bad law, and search Casetext’s comprehensive legal database

casetext.com

“A portion of the evidence produced at trial concerned the disconnection of one of the drivers in one of CU's Bose 901 loudspeakers. The plaintiff argues that the defendant tampered with the loudspeaker in order to alter subsequent test results. The Court shares the plaintiff's concern that the evidence in this case may have been tampered with at some time. Nevertheless, the Court is satisfied that CU's Bose 901 loudspeakers were in proper working condition at the critical time — when they were tested in 1969 and 1970. The impedance measurements taken in 1969 confirm that all the drivers were functioning at that time. If someone did tamper with the loudspeaker at a subsequent time it would, of course, be reprehensible, but it would not affect the Court's analysis of the evidence.”

Even Selinger when testifying would admit that it didn’t really move around, but in the end, being wrong or mistaken does not necessarily entail actual malice and it was important to protect First Amendment rights.

This was not actually a unanimous Supreme Court decision. Dissenting were those who thought the facts did suggest malice. Sandra Day O’Connor, William Rehnquist, and Byron White.

If this had happened today, you probably would have Bose posting something on their website to counter the claims made in Consumer Reports, Internet sleuths would have discovered that the author at Consumer Reports was also trying to commercialize his own speaker. Back then, we didn’t have this kind of discussion forum or avenues for direct to consumer communication.

So, while the right decision was to protect First Amendment rights, it also not as egregious for Bose to have filed the lawsuit since I think today, people would not appreciate a reviewer having such an obvious conflict of interest.