Audio Science in the Service of Art

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#1
“Audio Science in the service of art” is a philosophy in sound reproduction where the goal is to use science and technology to faithfully reproduce the art as the musical artist intended [1]. The art is the music, its performance, and the process of capturing it on the recording. The audio system is not part of the art, and should neither add, remove or editorialize the artist’s message. Audio components should not sound like musical instruments: Beethoven never wrote parts for loudspeaker and amplifier, so you shouldn’t be hearing them when listening to recordings of his music. The perfect audio system has no sonic personality, no musical qualities, and is the system that you notice the least.

Many audio companies do not subscribe to this scientific approach towards sound reproduction. Some companies will admit they simply cannot afford the infrastructure required to conduct proper scientific-based objective and subjective measurements. Anechoic chambers, dedicated listening rooms, speaker movers, listening test software, trained listening panels, and educated and trained scientific/engineering staff require significant long-term financial commitment to R&D. Other companies view sound reproduction as an artistic or marketing driven opportunity to screw with the art, and perform cosmetic surgery on the music: a little bass augmentation here, a little midrange tuck there, lift the treble here, and the facelift is complete. The problem with this approach is that recordings can be flawed in an infinite number of different ways. A cure-all bandaid solution will ultimately do more harm than good for most recordings, especially the good ones, which is a disservice to the art.

Faithful reproduction of the art assumes that the listening conditions in which the art was created are well defined. While there exists many accurate monitor loudspeakers in the marketplace today (e.g. the JBL LSR professional monitor series are designed to the same targets as our consumer loudspeakers) there is nothing that guarantees the artist will use them. Without meaningful loudspeaker and room calibration standards common to the professional and consumer audio industries, recordings and their reproduction remains a poorly controlled, highly variable process. For example, a survey of 164 professional recording studios in Europe using the same factory-calibrated 3-way monitor found up to 25 dB variations below 100 Hz measured at the mixing position. It’s no wonder the bass is so variable among different recordings!

Both the consumer and professional audio industries are trapped in a codependent relationship whereby the perceived sound quality of one’s product is interdependent on the others’. Known as the circle-of-confusion, this unfortunate state of affair can only be solved through a common standard that defines the performance of the loudspeaker and its acoustical interaction with the room.

Faithful reproduction of the art requires a thorough scientific understanding of the relationship between the perception and measurement of sound so that the important variables can be identified. Most audio scientists agree that the circle-of-confusion problem will not be solved until we optimize the performance of the loudspeaker and its acoustical interaction with the room acoustics. Our scientific understanding of what makes a loudspeaker sound accurate and neutral is already well understood.

This research question was studied at the Canadian National Research Council (NRC)[2],[3]and more recently, at Harman International [4]-[6], the parent company of loudspeaker brands Infinity, Harman Kardon, JBL and Revel. Using scientific-based, double-blind loudspeaker listening tests, scientists studied which physical parameter of loudspeaker performance were most related to listeners’ sound quality ratings, and overall preference. To eliminate the effects of sighted biases (e.g. brand, price, size, reputation) the tests were performed double-blind with other known listening test nuisance variables carefully controlled. The loudspeaker positional effects in comparative loudspeaker tests were solved by an automated speaker shuffler that positions each speaker into the exact same position.The tests were performed using trained listeners with normal hearing. More recent tests with untrained listeners indicate they also prefer the same loudspeakers as trained listeners,but give less consistent and discriminating ratings.

The results of this research found that the preferred loudspeakers in the listening tests were also the most accurate ones,based on a set of a comprehensive anechoic measurements. The measurements used high frequency resolution (48 points per octave), and employed spatial averaging to separate resonances from diffraction/acoustic interference effects. The frequency response curves were then spatially averaged into a family of curves, based on a survey of user's set ups in their rooms, rooms that represent the quality of the direct, early and late reflected sounds heard in the room. A mathematical preference model based on these measurements has been recently developed and can predict the loudspeaker preference with a correlation of r = 0.86 (the agreement between the predicted and measured ratings of 70 different loudspeakers). The model tells us that both the quality of the direct and reflected sounds produced by the loudspeaker are almost equally as important, and the bass quality accounts for about 30% of a listeners’ loudspeaker preference. This suggests that the low frequency interaction between the loudspeaker and room acoustics is something that cannot be ignored.

The acoustical interaction between the loudspeaker and the room is the remaining problem that must be solved to close the loop between the creation and reproduction of the art. At low frequencies (below 200-300 Hz), all listening rooms contain a natural set of resonances or room modes that can significantly boost and attenuate low frequencies below 200-300 Hz [7]. The level and frequency of these resonances will depend on the room’s dimensions, geometry and absorption characteristics, as well as the locations of the loudspeakers and listeners.

Fortunately, there are solutions today that can deal with these low frequency variations that occur between the loudspeaker and its acoustical interaction with the room. Bass in rooms can be tamed by judiciously placing the loudspeakers and listeners in locations where the room modes have the least effect [8]. In rectangular rooms, placing multiple (2 to 4) subwoofers in the room’s corners, wall midpoints,or at 25% and 75% along the wall dimension can cancel order modes via constructive interference, and not excite others. This solution has the benefit of reducing the spatial variance in bass quality across the listening area. Finally, equalization at single or multiple seating locations avoid exiting othersreduce some of the most deleterious effects. However, not all commercial room correction solutions are equal: some models can actually make the audio system sound worse than without correction.

In summary, our scientific understanding of the relationship between the measurement and perception of loudspeakers and rooms is quite mature. Measurements exist today that can accurately and reliably predict loudspeaker sound quality, and there are practical and effective solutions for dealing with their acoustical interaction with listening rooms at low frequencies.

It's time for the audio industry to finally close the loop between the recording and playback chains - to break out of the circle of confusion. A meaningful standard that defines the performance of the playback chain where the art is both created and reproduced would certainly be good place to start. Work on a new loudspeaker standard based on the NRC and Harman loudspeaker measurements is underway within the CEA and CEDIA standards groups. When completed, consumers will have access to product specifications that identify the excellent loudspeakers from the ones that are duds. Hopefully, the professional audio industry will adopt a similar standard so that consumers hear the music as it was intended by the artist. That would be the ultimate reward for audio science in the service of art.


References

[1] Floyd E. Toole. "Science in the service of art", Harman International white paper.

[2] Floyd E. Toole, "Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 1" J. AES Vol. 23, issue 4, pp. 227-235, April 1986. (download for free courtesy of Harman International).

[3]Floyd E. Toole, "Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 2," J. AES, Vol. 34, Issue 5, pp. 323-248, May 1986. (download for free courtesy of Harman International).

[4] Sean E. Olive, "Differences in Performance and Preference of Trained Versus Untrained Listeners in Loudspeaker Tests: A Case Study," J. AES, Vol. 51, issue 9, pp. 806-825, September 2003. (download for free courtesy of Harman International).

[5} Sean E. Olive Sean E. Olive, "A Multiple Regression Model for Predicting Loudspeaker Preferences using Objective Measurements: Part 1 -Listening Test Results," presented at the 116th AES Convention, May 2004.

[6] Sean E. Olive "A Multiple Regression Model for Predicting Loudspeaker Preferences using Objective Measurements: Part 2 - Development of the Model", presented at the 117th AES Convention, October 2004.

[7] Floyd E. Toole " Loudspeakers and Room - A Scientific Review", J. Audio Eng. Soc., Vol. 54, No. 6, June 2006 (download for free here courtesy of Harman International)

[8] Todd Welti and Allan Devantier,"Low Frequency Optimization Using Multiple Subwoofers", J. Audio Eng. Soc., Vol. 54, No. 5, May 2006 (download for free, courtesy of Harman International).
 
Last edited:

Steve Williams

Site Founder, Site Owner, Administrator
#2
Sean.

Great first contribution. A most interesting read.

Can you explain about the 48 points per octave and how it is done.
 

audioguy

WBF Founding Member
Apr 21, 2010
2,758
28
48
Near Atlanta, GA but not too near!
#3
Certainly as it pertains to loudspeakers, your quote of: "Other companies view sound reproduction as an artistic or marketing driven opportunity to screw with the art and perform cosmetic surgery on the music:" probably applies to 75% of all loudspeaker companies. Besides your company, and two or three others (the now deseased Dunlavy being one), virtually none use chambers. Some probably/may, use computer modeling and manufacturer provided driver specs to develop crossovers and ultimately the speaker, but that is about as far as it goes. And I would suggest that even some very well known and reasonably large (in the context of high end audio) speaker companies "voice" their speakers by ear (primarily).

Your research notwithstanding, my experience suggests that even when you develop the ability "so that consumers can easily differentiate between accurate loudspeakers and ones that are not", most consumers will not pick "accurate". I would think that accuracy implies a standard to which the reproduced sound can be compared. VERY few audiophiles attend live concerts and even fewer attend live concerts of un-amplified music. Given that assumption, how does a person determine accurate if they have no standard against which they can measure.

Great post, by the way !
 

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#4
Thanks Steve. Sure, we use a log sweep to measure our loudspeakers in the anechoic chamber. The sweep gives us 48 points per octave that are equally log-spaced in frequency from 10 Hz to 40 kHz.

The log sweep gives us much better frequency resolution at low frequencies, better signal-to-noise and is faster compared to what we used to use: a Maximum Length Sequence (MLS), which is a pseudo-random noise.
 

Steve Williams

Site Founder, Site Owner, Administrator
#5
Thanks Steve. Sure, we use a log sweep to measure our loudspeakers in the anechoic chamber. The sweep gives us 48 points per octave that are equally log-spaced in frequency from 10 Hz to 40 kHz.

The log sweep gives us much better frequency resolution at low frequencies, better signal-to-noise and is faster compared to what we used to use: a Maximum Length Sequence (MLS), which is a pseudo-random noise.
thanks Sean
 

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#6
Certainly as it pertains to loudspeakers, your quote of: "Other companies view sound reproduction as an artistic or marketing driven opportunity to screw with the art and perform cosmetic surgery on the music:" probably applies to 75% of all loudspeaker companies. Besides your company, and two or three others (the now deseased Dunlavy being one), virtually none use chambers. Some probably/may, use computer modeling and manufacturer provided driver specs to develop crossovers and ultimately the speaker, but that is about as far as it goes. And I would suggest that even some very well known and reasonably large (in the context of high end audio) speaker companies "voice" their speakers by ear (primarily).

Your research notwithstanding, my experience suggests that even when you develop the ability "so that consumers can easily differentiate between accurate loudspeakers and ones that are not", most consumers will not pick "accurate". I would think that accuracy implies a standard to which the reproduced sound can be compared. VERY few audiophiles attend live concerts and even fewer attend live concerts of un-amplified music. Given that assumption, how does a person determine accurate if they have no standard against which they can measure.

Great post, by the way !
I know some loudspeaker companies like PSB, Paradigm, Axiom and Definitive Technology, B&W own or rent anechoic chambers to test their loudspeakers. Surprisingly, some companies have chambers but only do a few measurements on and off-axis, which is frankly inexcusable. That is not enough measurements to fully characterize the sound radiated by the loudspeaker. We do measurements every 10 degrees, 360 degrees in both horizontal and vertical orbits, for a total of 70 measurements.

It doesn't surprise me that some companies don't measure their speakers or tune them by ear.I've tested some of those speakers over the last 20 years, and it's obvious they were not properly evaluated or measured.

The CEDIA/CEA loudspeaker standards will be based on comprehensive anechoic measurements that allow easy interpretation of their sound quality. Eventually there may be an overall sound quality rating based on those measurements.

If a consumer is told that speaker Brand A has a sound quality of 90/100 and speaker brand B is rated 50/100 -- do you really think the consumer will choose the one that is rated 50/100 (the one that sounds less neutral)?

When I shop at Costco the wines rated over 90 by Wine Spectator are usually almost sold out, and the ones rated less than 85 are usually still plentiful. Consumer purchases are highly influenced by simple ratings like that, particularly if the ratings are meaningful and come from a trusted source.

Probably luxury goods like high-end audio and wine are less influenced by ratings and real quality versus perceived quality. For some people, it's just about price, exclusivity and the status that comes with ownership.
 
Last edited:

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#8
Sean, can you please explain what will be used in CEDIA/CEA speaker measurement standards?

Thanks,
Amir,

The CEA has a loudspeaker standards committee that includes representatives from different manufacturers including Harman (Floyd Toole and Allan Devantier are representing us). The final draft is not completed and approved, but I am told the loudspeaker measurements are likely to be similar to what we currently use at Harman:

1) Anechoic frequency response made a 2 meters or greater with at least 1/20-octave resolution
2) Repeated at every 10 degrees in horizontal and vertical orbits
3) Calculate and plot the following spatial averages:

a) On-axis response
b) Listening window
c) Early Reflections
d)Total Radiated Sound Power
e) Early Reflection Directivity Index
f) Sound Power Directivity Index

I've included few slides here that explain the measurements and an illustrate example of how the measurements correlate with listeners' preference ratings (last slide).
 

audioguy

WBF Founding Member
Apr 21, 2010
2,758
28
48
Near Atlanta, GA but not too near!
#9
What about measuring step response? While you may not agree with him, here is a quote from John Dunlavy in an interview with Stereophile: "Of all of the measurements that we take that come more close to predicting, or most close to predicting how a speaker is going to emulate a properly recorded live performance, it's step response. Everything is implicit if you know how to interpret a step response...if my life depended upon my describing what I thought a speaker was going to sound like, all other factors being equal, I would choose step response. And feel very confident that I would be spot-on."

Your comment about people preferring a speaker who gets a 90 score versus a 50 score would certainly apply to that category who buys on specs today but I would suggest that many who purchase in the high end market do not fall into that group.

I am a BIG believer in the concept of building truly accurate loudspeakers. And I'm all for the development of the standards you have mentioned. And I also believe that those standards will help drive sales for those companies whose products measure best -- for the mid-fi market on down.

However, I also spent 10 years selling and installing digital room correction systems (primarily SigTech) and heard hundreds and hundreds of systems in audiophile homes (these were mostly mega buck systems). What I found interesting is that many, many audiophiles preferred certain coloration over what clearly would have measured much more accurately. Just read the threads in WBF and it is clear the there is no consensus on this whole accuracy subject. Or go read some of the threads on certain loudspeakers on other forums and you will note the same thing.

Sign ME up as a believer. But on the subject of getting most "high enders" to purchase based on a set of standard accuracy measurements,, I guess you could also call me a major cynic. But I hope I'm wrong about that.
 
Last edited:

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#10
Thanks Audioguy. The step response of the loudspeaker can be calculated from the impulse response and tells you something about the time-coherence of the drivers. The speaker is time-coherent if the woofer/mid/tweeter arrive at the microphone at the same time: it should be pointed out that this happens at only 1 point in space for 1 ear since the drivers are physically separated by some distance - move your ear, and all bets are off.

Most loudspeakers are not time-coherent, and frankly I don't think this is very important in terms of the loudspeaker's perceived sound quality. At mid/high frequencies we are relatively insensitive to phase/group delay caused by the cross-over, or typical driver offsets.

More important is how well the drivers sum together and how well matched their directivities are at the cross-over region. This can be better viewed by looking at the frequency response measured all around the loudspeaker.

John Atkinson wrote a nice article about the step response over at Stereophile.. If you read his paper, he independently came to the same conclusion as we did after reviewing and measuring 350 loudspeakers over many years: the frequency response is the best indicator of how good the loudspeaker sounds. I quote him:

Floyd Toole, now with Harman International but then with Canada's National Research Council, in his summary of research at the NRC into loudspeaker performance that is described in two classic 1986 papers [32, 33], concluded thusly: "The advocates of accurate waveform reproduction, implying both accurate amplitude and phase responses, are in a particularly awkward situation. In spite of the considerable engineering appeal of this concept, practical tests have yielded little evidence of listener sensitivity to this factor...the limited results lend support for the popular view that the effects of phase are clearly subordinate to amplitude response."

This is also my view. Of the 350 or so loudspeakers I have measured, there is no correlation between whether or not they are time-coherent and whether or not they are recommended by a Stereophile reviewer. However, I feel that if other factors have been optimized—on-axis response, off-axis dispersion, absence of resonance-related problems, and good linearity—like a little bit of chicken soup, time coherence (hence minimal acoustic phase error) cannot hurt. In my admittedly anecdotal experience, a speaker that is time-coherent (on the listening axis) does have a small edge when it comes to presenting a stereo soundstage, in terms of image focus and image depth. But time coherence does not compensate for coloration, poor presentation of instrumental timbres, a perverse frequency balance, or high levels of nonlinear distortion.
 
Last edited:

Jeff Fritz

[Industry Expert]
Jun 7, 2010
434
5
16
#11
More important is how well the drivers sum together and how well matched their directivities are at the cross-over region. This can be better viewed by looking at the frequency response measured all around the loudspeaker.
This certainly matches my subjective review experiences as well as with speakers that I've heard that we've measured at NRC. Smooth off-axis response is a key.

I've also come to the opinion the last few years that speakers that have controlled off-axis response almost never sound bad due to sub-optimal positioning. While you can improve them considerably -- particularly in the bass -- through precise positioning, they never sound just plain horrible. However, speakers that are so sensitive to positining that they can go from truly bad to truly great, typically have poor off-axis behavior.

Contrary to the audiophile belief that great speakers are the ones that have to lock-in to sound great (or will otherwise be bad), I now see this as a flaw in the design. It can be measured quite easily.
 

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#12
This certainly matches my subjective review experiences as well as with speakers that I've heard that we've measured at NRC. Smooth off-axis response is a key.

I've also come to the opinion the last few years that speakers that have controlled off-axis response almost never sound bad due to sub-optimal positioning. While you can improve them considerably -- particularly in the bass -- through precise positioning, they never sound just plain horrible. However, speakers that are so sensitive to positining that they can go from truly bad to truly great, typically have poor off-axis behavior.

Contrary to the audiophile belief that great speakers are the ones that have to lock-in to sound great (or will otherwise be bad), I now see this as a flaw in the design. It can be measured quite easily.
Hi Jeffrey,

Great post! Your experience confirms that the scientific approach to the design and testing of loudspeakers works!
 
Last edited:

Gregadd

WBF Founding Member
Apr 20, 2010
6,606
54
48
Metro DC
#13
Sean I have to admit I still don't get it. Maybe you can recommend a product that was designed with the scientific method and I can go listen to it.:confused:
 
#14
Sean I have to admit I still don't get it. Maybe you can recommend a product that was designed with the scientific method and I can go listen to it.:confused:
I too would like to know which loudspeakers "pass and fail" this testing procedure. It would be interesting to see how it matches what I prefer based on 45 years listening experience.

Not mentioned so far, in my opinion even with a "perfect" speaker design the associated components make or break the sound.
 

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#15
Sean I have to admit I still don't get it. Maybe you can recommend a product that was designed with the scientific method and I can go listen to it.:confused:
Most Harman loudspeaker models (Infinity, JBL, Revel, HK) are designed to meet the same performance targets: flat on-axis frequency response, smooth off-axis response/directivity, and wide bandwidth. Of course, how well they achieve those targets depends on the technologies in the speaker, price budget, etc .As you pay more money, generally the loudspeaker should more closely meet those targets, and have more extended bass and highs, play louder with lower distortion, be generally more refined in sound quality/acoustical performance, and have finer industrial design features. The more expensive products have hand-adjusted/trimmed cross-over components when product is manufactured and finally tested.

The Revel models (e.g. Salon 2 ) or JBL Synthesis (e.g Everest or Project Array series) are good examples at the higher end of the price scale. At the lower end of the price scale, the Infinity Primus series would a good example. The Primus 360 is about $500 a pair (see subjective and objective performance of the Primus 362 in in slide 28 of the attached PDFPDF.

Besides doing well in our own competitive benchmark tests, the products I mentioned have received critical acclaim in magazines like Stereophile (JBL Project Array 1400 review, Revel Salon II review and Infinity Primus 360 review)... It's nice when you get independent confirmation by satisfied reviewers and customers, that the science works.
 
Last edited:

Gregadd

WBF Founding Member
Apr 20, 2010
6,606
54
48
Metro DC
#16
With the exception of Revel the word mid-fi seems to float around in my head. Improving products across the band is a laudable goal. The question is why do we need scientific research to achieve those gaols."...are designed to meet the same performance targets: flat on-axis frequency response, smooth off-axis response/directivity, and wide bandwidth..." We have long since discovered how to do this and verify it through scientific measurements. How would that design process differ from say David Wilson and Wilson Audio? IMO one of the most neutral designs and his attention to detail borders on anal compulsive.
To achieve the goals you put forth we don't need so much scientific advancement but motivation to excel in these areas and honest evaluation of the results.
Do you see my problem? It is entirely likely that we have different ideas about the definition of advancing the SOTA. My idea is taking the best we have and pushing it closer to the recreation of live music. Pushing the envelope as it were.
Over my many years I have owned many products that were not SOTA but wrung every ounce of performance from that design given their design parameters and price point. In fact I think I own three of those products now.
 

sasully

New Member
Jun 30, 2010
99
0
0
#17
With the exception of Revel the word mid-fi seems to float around in my head.
You can thank the 'high end' press for that. It means nothing in relation to objective sound reproduction quality. Lots of 'mid-fi' gear compared favorably to 'audiophile' gear. Olive's and Toole's own research showed a highly-rated loudspeaker doing poorly when subjected to a rigorous test.


Improving products across the band is a laudable goal. The question is why do we need scientific research to achieve those gaols."...are designed to meet the same performance targets: flat on-axis frequency response, smooth off-axis response/directivity, and wide bandwidth..." We have long since discovered how to do this and verify it through scientific measurements. How would that design process differ from say David Wilson and Wilson Audio? IMO one of the most neutral designs and his attention to detail borders on anal compulsive.
To achieve the goals you put forth we don't need so much scientific advancement but motivation to excel in these areas and honest evaluation of the results.

...which requires blind tests, i.e, scientific methods.


Do you see my problem? It is entirely likely that we have different ideas about the definition of advancing the SOTA. My idea is taking the best we have and pushing it closer to the recreation of live music.


...which requires blind tests, i.e, scientific methods.

Pushing the envelope as it were.
Over my many years I have owned many products that were not SOTA but wrung every ounce of performance from that design given their design parameters and price point. In fact I think I own three of those products now.

Loudspeakers (and microphones) are technology that's still so far from 'accurate' compared to other components of modern record/play system, that I really can't understand how you can say we don't need any more scientific research.
 

Jeff Fritz

[Industry Expert]
Jun 7, 2010
434
5
16
#18
With the exception of Revel the word mid-fi seems to float around in my head. Improving products across the band is a laudable goal. The question is why do we need scientific research to achieve those gaols."...are designed to meet the same performance targets: flat on-axis frequency response, smooth off-axis response/directivity, and wide bandwidth..." We have long since discovered how to do this and verify it through scientific measurements. How would that design process differ from say David Wilson and Wilson Audio? IMO one of the most neutral designs and his attention to detail borders on anal compulsive.
To achieve the goals you put forth we don't need so much scientific advancement but motivation to excel in these areas and honest evaluation of the results.
Do you see my problem? It is entirely likely that we have different ideas about the definition of advancing the SOTA. My idea is taking the best we have and pushing it closer to the recreation of live music. Pushing the envelope as it were.
In my mind the best loudspeaker designers today have these performance characteristics in common. If you talk with Payor or Wolf or Andrew Jones they will all tell you that these measurements that Olive is touting are what they also look at, among many other things. This is really just solid loudspeaker engineering and the top guys really don't disagree on it too much. They each have their methods of getting there, and each has certain areas they put above others, but good on- and off-axis FR, for instance, is common to them all. As are a host of other "basics" such as low diffraction, inert cabinets, driver break-up modes well outside of the passband, etc.
 

tmallin

WBF Technical Expert
May 19, 2010
339
26
28
66
Chicagoland
#19
With the exception of Revel the word mid-fi seems to float around in my head. Improving products across the band is a laudable goal. The question is why do we need scientific research to achieve those gaols."...are designed to meet the same performance targets: flat on-axis frequency response, smooth off-axis response/directivity, and wide bandwidth..." We have long since discovered how to do this and verify it through scientific measurements. How would that design process differ from say David Wilson and Wilson Audio? IMO one of the most neutral designs and his attention to detail borders on anal compulsive.
To achieve the goals you put forth we don't need so much scientific advancement but motivation to excel in these areas and honest evaluation of the results.
Do you see my problem? It is entirely likely that we have different ideas about the definition of advancing the SOTA. My idea is taking the best we have and pushing it closer to the recreation of live music. Pushing the envelope as it were.
Over my many years I have owned many products that were not SOTA but wrung every ounce of performance from that design given their design parameters and price point. In fact I think I own three of those products now.
I know that some of this forum's organizers use Wilson speakers. I have to say, however, that to the extent Wilson speakers sound good and are popular, it cannot be because of any unusually good results they achieve in standard frequency response tests. Just look at any of Stereophile's measurements of their speakers (the current issue, not yet on line, measures the Sasha). As just one example, here is the Maxx II. Compare that to, for example, this PSB model at a small fraction of the price and you will see what I mean.
 

tonmeister2008

WBF Technical Expert
Jun 20, 2010
210
0
0
Westlake Village,CA
#20
With the exception of Revel the word mid-fi seems to float around in my head. Improving products across the band is a laudable goal. The question is why do we need scientific research to achieve those gaols."...are designed to meet the same performance targets: flat on-axis frequency response, smooth off-axis response/directivity, and wide bandwidth..." We have long since discovered how to do this and verify it through scientific measurements. How would that design process differ from say David Wilson and Wilson Audio? IMO one of the most neutral designs and his attention to detail borders on anal compulsive.
To achieve the goals you put forth we don't need so much scientific advancement but motivation to excel in these areas and honest evaluation of the results.
Do you see my problem? It is entirely likely that we have different ideas about the definition of advancing the SOTA. My idea is taking the best we have and pushing it closer to the recreation of live music. Pushing the envelope as it were.
Over my many years I have owned many products that were not SOTA but wrung every ounce of performance from that design given their design parameters and price point. In fact I think I own three of those products now.
Not sure what you mean by "mid-fi": does it mean poor sound quality or the cost of the product? The two are often negatively correlated unless the product design is based on sound science and engineering.

We make products at all price points from $30k per speaker down to $100-200. At the higher price points, there should ideally be fewer compromises in sound quality because there is more money, engineering and technology to throw at the product.

At the lower price points, due to restrictions in size, form factor, etc there are ultimately compromises or tradeoffs in sound quality that have to be made. From an engineering/scientific aspect, this is actually a more challenging exercise in some ways. Deciding what the best sound quality tradeoffs are in terms of on/off axis response, bass extension, directivity, max SPL, distortion, etc is an area is an ongoing area of scientific research at Harman. Audio scientists still do not clearly understand the relationship between the perception of nonlinear distortion and its measurement. Reducing nonlinear distortion in loudspeakers at higher SPLs comes at great added cost to the speaker, and therefore, it is good to understand the psychoacoustics in order to optimize the perceptual versus cost benefits.

Another area that needs scientific research is the acoustical interaction between the loudspeaker and the room. In my opinion, this is the single largest obstacle in getting more consistent and accurate recorded and reproduced sound. If we can solve the problem, we will significantly advance the SOTA for everyone.

Harman or a competitor can build the world's most accurate speaker, but as soon as the customer puts it in their room all bets are off. The room dominates the quality of sounds heard below 200-300 Hz. Bass quality accounts for 30% of the listeners' preference according to our research, which is something that cannot be ignored. I believe Harman is one of the leaders in this area in terms of research and technology. We've developed our own room/loudspeaker measurement system, a room correction algorithm that works, and a multiple subwoofer bass management solution we call Sound Field Management that reduces the spatial variance in bass performance across a seating area. These technologies are currently in JBL Synthesis and Revel system packages, and will soon be in many more Harman products including professional ones used to make the art.

These are just a few of the active scientific research projects at Harman that are helping to advance the SOTA at both higher and lower product price points. Our philosophy is to optimize the sound quality of the product regardless of its cost. Good sound shouldn't be exclusive to the wealthy.
 
Last edited:

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. A place where audiophiles and audio companies discuss existing and new audio products, music servers, music streamers and computer audio, digital to audio convertors (DACS), turntables, phono stages, cartridges, reel to reel, speakers, headphones, tube amplifiers and solid state amplification. Founded in 2010 What's Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals we enjoy learning about new things and meeting new people and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing