Article on Harman Audio in "Test and Measurement World"

gregz

gregz

Full Audioholic
This month's issue of "Test and Measurement World" had a writeup on Harman Audio's methodology of applying their own unique measurement criteria to build the "best sounding inexpensive loudspeakers."

Harman Audio, for those of you who didn't know, currently owns JBL, Infinity, and of course Harman Audio speakers.

Aside from how successfully they're balancing their findings with cost saving techniques, they had some interesting notions:

1) They downplay the importance of on-axis frequency response flatness as measured on a DB meter (industry standard for response curve and rating)

2) Their designs attempt to compensate for early reflections caused by potentially poor placements in people's homes (they gave out sets of speakers to 15 people and then went to their homes to measure)

3) They conduct blind A/B/C/D testing of their speakers on people who:
a) Have no prior critical listening skill or bias
b) Have gone through their special "training" on how they should be listening

4) Any audible difference or quality in speakers is measurable objectively

For those of us who arrange our listening rooms to properly accomodate our speakers away from back and side walls and furniture, it seems a bad thing to have the speakers designed to avoid early reflection distortion. Wouldn't that potentially lead to poor off-axis response, narrowing the sweet spot?

As for using specially trained laymen as listeners, that one truly depends upon target audience. If you're trying to cater to the masses, you'll use a cross section of the masses to make your speakers match their preference. I can't fault them for that, though it's not likely to produce an accurate speaker as it will a "catchy" speaker that people might be initially impressed with pumping out Pop music at Best Buy.

Personally, I'd want a group of classical or jazz fans & musicians to sit in a small theatre listening to a live acoustic performance, then go directly next door to a listening room where a recording of the same group is being played back on several different speakers in a blind test.

Is such fidelity measurable? Or would the qualities that separate a good speaker from a bad one too inconsistent and, well, subjectively human in nature? For instance, how would you define something as funny?

Feedback? Snide remarks?
 
JoeE SP9

JoeE SP9

Senior Audioholic
I wonder what "inexpensive" means. I also wonder if in the future they will apply the same design philosophy to more expensive speakers. :cool:
 
gregz

gregz

Full Audioholic
Well, inexpensive within the Infinity brand name means that they start at $150/pr for bookshelfs and $200/pr for floor standing. Having also listened to the $1,200/pr floor standing versions at a store, I'd say the same designers were at work on those as well because they had similar sound "qualities"...

The magazine's editor's note in the front of the magazine shows his lack of audio awareness as well as his stout arrogance with the line:

"Unlike preferences for wine, loudspeaker pereferences aren't a matter of personal taste."

He invites those who disagree to go to www.tmworld.com/audio to respond. I think I'll drop in and say "hi."
 
JoeE SP9

JoeE SP9

Senior Audioholic
I lost faith and interest in Infinity speakers when Arnie Nudell sold the company. :cool:
 
Rip Van Woofer

Rip Van Woofer

Audioholic General
The brains behind Harman's speaker testing are Floyd Toole and Sean Olive, who base Harman's testing methodology on the famous work Toole and Olive did at Canada's NRC. That work, and the testing methodolgies that resulted, are also big influences on Canadian speaker makers like PSB and Paradigm.

Toole is big on accuracy. Much of Toole's work at the NRC demonstrated that, in blind testing, most people regardless of "sophistication" prefer accurate speakers to inaccurate speakers when given a direct comparison. More broadly, Toole did a lot of groungbreaking work establishing the relationhips between measurable, objective criteria and listener preferences.

Narrow vs. wide polar response is a subject of continuing controversy in speaker design; there are good arguments for and against each. Either way, most practitioners agree that the polar response and off-axix dropoff should be smooth and regular without things like big dips in the crossover region.

Whatever Arnie Nudell's qualities are or were in the early days of Infinity, he is now mainly a shyster pushing grossly overpriced speakers, IMO.
 
Rip Van Woofer

Rip Van Woofer

Audioholic General
gregz said:
The magazine's editor's note in the front of the magazine shows his lack of audio awareness as well as his stout arrogance with the line:

"Unlike preferences for wine, loudspeaker pereferences aren't a matter of personal taste."
Wrong: It is not the editor's opinion. The editor goes on to say, in the article, that "at least that's the view of Harman International engineers..."

Read the full article.
 
gregz

gregz

Full Audioholic
Fancy meeting you here, Rip. This is just the type of discussion I was hoping to generate. :D

Regarding my quote from the editor, while he mostly paraphrases Harman Audio's findings, he does cast his own opinion into the jar with them quite clearly.

But that's not the interesting part of the discussion.

While nobody in their right mind would claim they're designing innacurate speakers and additional objective measurement tools are certainly a great aid in design testing, I do take issue with the notion that there is no personal taste involved in loudspeaker preference.

That statement, coupled with the idea that lay listeners give the same response as "sophisticated" listeners makes me really scratch my head.

Rather than argue my point, I'd be more interested if you could expand on these ideas, because they not only go against my logic, but go against quite a bit of my anecdotal experience and observations.
 

plhart

Audioholic
Correcting inaccuracies and misconceptions

"This month's issue of "Test and Measurement World" had a write-up on Harman Audio's methodology of applying their own unique measurement criteria to build the "best sounding inexpensive loudspeakers."

”Harman Audio, for those of you who didn't know, currently owns JBL, Infinity, and of course Harman Audio speakers.”


Harman International owns the following speaker brands: JBL, Infinity, Harman-Kardon (mostly used for multimedia/computer speakers) and Revel. Engineering, design and testing for these brands takes place at Harman’s Northridge, CA facility.

Aside from how successfully they're balancing their findings with cost saving techniques, they had some interesting notions:

1) They downplay the importance of on-axis frequency response flatness as measured on a DB meter (industry standard for response curve and rating)


Harman does not “downplay” the importance of on-axis frequency response per say. More correctly stated, through years of research, qualified by rigorous double blind testing Harman has determined (and published papers in the Journal of the Audio Engineering Society) that on-axis frequency response is but one of several important and measurable parameters that define and identify a speaker’s performance envelope.

“DB” meters are NOT the “industry standard for response curve and rating”. It is generally agreed world-wide that a reflection-free, free-air frequency response taken by recognized loudspeaker testing programs such as LMS, Sys-ED, Clio or MLLSA, etc. using a properly calibrated microphone is the accepted method for accurate measurement. Such programs can be accurate to within 2Hz if so desired but the measurement takes a bit more time. Lacking that, a 4 pi anechoic chamber, preferably accurate down to 20Hz, is utilized. Smaller chambers such as Harman’s can be calibrated to the 0.5dB accuracy as noted in the article.


”2) Their designs attempt to compensate for early reflections caused by potentially poor placements in people's homes (they gave out sets of speakers to 15 people and then went to their homes to measure)”

Again, improperly stated. Harman’s designs do NOT “attempt to compensate” for early reflections. Harman’s engineers design to a fairly flat on-axis frequency response with a similar off- axis response. The difference being that as the frequency increases the off-axis response is expected to decrease smoothly, with no apparent dips showing, as the speaker system transitions through the crossover points.

I will detail, where, within the “flat frequency response” dictum Harman engineers often deviate by model and by price point, so as to achieve the best balance of measured And psychoacoustically flat response in a future article. There is quite a bit a wiggle room within a ±2dB range if you know what you’re doing and you know your competition.

Early reflections from a “flat on-axis & polar response” speaker system will have all frequencies reflected evenly if no absorption is applied at the point of the first axial reflection. So the system will act more like an ideal “acoustic mirror”. This effect is often appealing to those who like to think that their speakers can “image way beyond their enclosures” or produce “bigger than natural” sound.

“3) They conduct blind A/B/C/D testing of their speakers on people who:
a) Have no prior critical listening skill or bias
b) Have gone through their special "training" on how they should be listening”


Correctly stated, Sean Olive based his now famous paper “Differences in Performance and Preference of Trained versus Untrained Listeners in Loudspeaker Tests: A Case Study” on 3), a) and b) above.

”4) Any audible difference or quality in speakers is measurable objectively”

I was one of Harman’s trained listeners. I averaged about 3 test sessions per week. I have heard (and believe) that the conclusions of Sean’s paper are entirely accurate. If you are a member of the AES you can obtain the full text of Sean’s paper through www.aes.com

“For those of us who arrange our listening rooms to properly accomodate our speakers away from back and side walls and furniture, it seems a bad thing to have the speakers designed to avoid early reflection distortion. Wouldn't that potentially lead to poor off-axis response, narrowing the sweet spot?”

An improper assertion > “designed to avoid early reflection distortion”. A flat polar response will yield, at the ears, a time delayed but spectrally balanced image, seeming larger, but NOT distorted by narrower-band frequency aberrations. This is, by definition, excellent polar frequency response and it yields the widest possible sweet spot.

”As for using specially trained laymen as listeners, that one truly depends upon target audience. If you're trying to cater to the masses, you'll use a cross section of the masses to make your speakers match their preference. I can't fault them for that, though it's not likely to produce an accurate speaker as it will a "catchy" speaker that people might be initially impressed with pumping out Pop music at Best Buy.”

Read Sean’s paper. To quote “The loudspeaker preferences of trained listeners were generally the same as those measured using a group of nominally untrained listeners composed of audio retailers, marketing and sales people, audio reviewers and college students…..The most preferred loudspeakers had the smoothest, flattest, and most extended frequency responses maintained uniformly off axis.”

“Personally, I'd want a group of classical or jazz fans & musicians to sit in a small theatre listening to a live acoustic performance, then go directly next door to a listening room where a recording of the same group is being played back on several different speakers in a blind test.”

Again, Sean’s paper showed that both trained and untrained listeners would come to the same conclusions regarding response. The only difference was that trained listeners would be able to come to those same conclusions 3 to 27 times sooner.

”Is such fidelity measurable? Or would the qualities that separate a good speaker from a bad one too inconsistent and, well, subjectively human in nature?

Yes, such “fidelity” (truth) has been proven, through hundreds of listeners, both trained and untrained, while listening double-blind, to be definable (see above).

Well, inexpensive within the Infinity brand name means that they start at $150/pr for bookshelfs and $200/pr for floor standing. Having also listened to the $1,200/pr floor standing versions at a store, I'd say the same designers were at work on those as well because they had similar sound "qualities"...

There are six full time Systems Engineers at Harman. And yes the same guy will usually design an entire line.

“The magazine's editor's note in the front of the magazine shows his lack of audio awareness as well as his stout arrogance with the line:

"Unlike preferences for wine, loudspeaker preferences aren't a matter of personal taste."”


If you had had the opportunity to attend Sean’s October presentation to Los Angeles Section of the AES you would understand the genesis of this statement. Sean starts his presentation by demonstrating that there can be no perfect wine because different wines have different and more prized taste qualities such as bouquet, aroma, body etc. (And there are many, many varieties with many, many anticipated "best of" qualities.) He shows a slide of a wine qualification “taste wheel”. Yes, this is an actual double-wheel, made of cardstock, with a pin in the center which has the different adjectives usually ascribed to specific varieties of wine, arrayed around the wheel. This makes the judging of “best” in any varietals category a matter of evaluating the proportions of an adjective which a particular wine may possess.

He invites those who disagree to go to www.tmworld.com/audio to respond. I think I'll drop in and say "hi."

Yes, say “hi” and ask the writer if he too had heard Sean’s presentation before writing his article.

“I lost faith and interest in Infinity speakers when Arnie Nudell sold the company.”

So you would prefer that Infinity speakers still be designed with dips at specific frequencies going down to 1 ohm? That doesn’t happen anymore. No speaker is Ever designed which dips below 4 ohms. For any of the Harman brands. Department policy.
 
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gregz

gregz

Full Audioholic
Eghads; the MOTHERLOAD!! :D Hi plhart.

I typed up a very long response, hit "SUBMIT REPLY" and got the dreaded red page informing me the server was temorarily down. And I couldn't go "back." :mad:

...sigh... Another day
 
JoeE SP9

JoeE SP9

Senior Audioholic
The fact that a given speaker has a difficult impedence curve really isn't that important to me. If I purchased a speaker that was that difficult a load I would purchase appropriate amplification. I suppose I just never got over the sound I heard from some IRS Beta's I heard years ago. :cool:
 
gregz

gregz

Full Audioholic
Ok, I'm back. Let's try this again...

I think you set me straight on the off-axis bit. If I may sum up what you said, they're looking for smooth off axis roll-off rather than less off-axis response. I see that as a good thing.

Correctly stated, Sean Olive based his now famous paper “Differences in Performance and Preference of Trained versus Untrained Listeners in Loudspeaker Tests: A Case Study".
I don't know about the "now famous paper" part; some might say "infamous." :D There is still much dissention in the ranks of the audio world (and needless to say in my teeny little warped world).

I was one of Harman’s trained listeners. I averaged about 3 test sessions per week. I have heard (and believe) that the conclusions of Sean’s paper are entirely accurate.
Ok, that gets my attention. I had several questions about the test methodology, such as what speakers were used for comparison and what type of music was used.

By the way, I'm by no means on a witch hunt as I see no motive for Harman International to skew their results. They're obviously implementing their time and resources to a productive end. The fact that I question or even downright disagree with a few of their test philosophies is cause for interesting discussion, nothing more.

Read Sean’s paper. To quote “The loudspeaker preferences of trained listeners were generally the same as those measured using a group of nominally untrained listeners composed of audio retailers, marketing and sales people, audio reviewers and college students…..The most preferred loudspeakers had the smoothest, flattest, and most extended frequency responses maintained uniformly off axis.”
That would be a good read. Indeed, I'm coming to the table without all of the pieces. That's where you have been helpfully filling in the gaps. Where can I find Sean's paper?

Yes, such “fidelity” (truth) has been proven, through hundreds of listeners, both trained and untrained, while listening double-blind, to be definable.
Careful, saying something has been "proven" almost sounds dogmatic, even if the test had been conducted on more than hundreds, or confirmed by independent parties. I'm more from the Carl Popper camp.

If you had had the opportunity to attend Sean’s October presentation to Los Angeles Section of the AES you would understand the genesis of this statement. Sean starts his presentation by demonstrating that there can be no perfect wine ....
Lots of additional support on why wine is not univeral in appeal which everybody already agrees upon. That hardly proves that loudspeaker preference is.

Scientifically, anecdotal evidence is not very strong. Sociologically, it's worthless. Still, we base many of our opinions from our own experiences, just as you did from yours as a listener. The problem is that I have not only witnessed people in audio stores going for the more catchy sounding speakers, I have experienced ignorance first hand when I bought my first pair of speakers that I thought had "nice clear trebble." After a year with those miserable things, I thought my ears would bleed every time a symbol scrached its way across those electric hissing pieces of bacon.

I experienced it again second hand when a friend of mine dragged me out to help him pick out a new pair of speakers. He chose the ones with the accented trebble and overly warm bass, while I pointed to a lovely pair of neutral speakers. "Those sound dull," he said, and bought the Cerwin Vegas anyway.

But beyond seeing lay listeners pick unrealistic sounding speakers with peaky curves, I have a deeper issue that I'll bring to the table.

Basically, speakers suck. It doesn't matter if they're electrostatic, electrodynamic, or hybrid. Reproducing audio accurately is no longer a difficult task in the electronics chain, but in a speaker design, every decision becomes a compromise to some extent between imaging, frequency range, frequency response flatness, proper dampening of moving mass, etc. This is where the human element could be coming into play. What if my ears are more sensitive to phase coherence than yours are to a frequency peak at 5,000Hz? Would we still choose the same speaker as having the best fidelity? If my background was drumming, wouldn't I eliminate the poorly dampened woofers from my selection that might not be eliminated by someone else who has much more sensitivity to the woody resonance of a string passage?

That there are so many thousand dollar speakers that sound different seems a testament to the fact that loudspeaker preference is not universal. In fact, the staggering volume of less expensive speakers that are downright distortion boxes suggests that lay listeners are not choosing more accurate speakers over the innacurate ones. I'm not saying these constitute proof by any means, but the market does seem to show a different reality than the one represented by universal taste for accuracy.
 
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plhart

Audioholic
"The fact that a given speaker has a difficult impedence curve really isn't that important to me. If I purchased a speaker that was that difficult a load I would purchase appropriate amplification. I suppose I just never got over the sound I heard from some IRS Beta's I heard years ago."


The IRS Betas were around $10K through their many incarnations so they were naturally mated with massively built and priced (>$3K) two-channel amps of the period. No problem if you were a rabid audiophile in the seventies and early eighties. Stereophile and Absolute Sound would tell fans just what amps actually could drive such a ridiculous, and in my opinion, flawed speaker design.

When, however, Infinity tried the trickle-down-to-lower-price-points strategy by using the EMIM mids and EMIT tweeters in lower price point 3-ways they almost drove the company into the ground. Problem was lower price-point speakers are mated with lower cost ($1000) receivers and Japanese separates ($1200) which could not handle violent current swings without tripping protection circuitry or worse, blowning up the amp. The salesmen in the more mass market oriented hi-fi emporiums naturally shyed away in droves from selling these speakers once the word got around that the saleman should be prepared for a swift return of (now-used or blown-up)merchandise by an irate customer.
 
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plhart

Audioholic
A sighted test procedure recommendation

"Ok, I'm back. Let's try this again...

I think you set me straight on the off-axis bit. If I may sum up what you said, they're looking for smooth off axis roll-off rather than less off-axis response. I see that as a good thing."


Glad you agree.

"Correctly stated, Sean Olive based his now famous paper “Differences in Performance and Preference of Trained versus Untrained Listeners in Loudspeaker Tests: A Case Study".

I don't know about the "now famous paper" part; some might say "infamous." There is still much dissention in the ranks of the audio world (and needless to say in my teeny little warped world)."


Like the American Medical Association which publishes its research findings in JAMA, research papers in the audio world are generally presented to one’s recognized audio engineer peer group, the Audio Engineering Society. Go to www.aes.com and follow the links to where you can put in Sean’s name. I’m not sure how much a reprint costs for non-members.

I am not sure which “audio world” you are referring to but I can tell you that within the AES I know of no legitimate challenge that has been mounted in deference to the findings reported in Sean’s paper.

"Scientifically, anecdotal evidence is not very strong. Sociologically, it's worthless. Still, we base many of our opinions from our own experiences, just as you did from yours as a listener. The problem is that I have not only witnessed people in audio stores going for the more catchy sounding speakers, I have experienced ignorance first hand when I bought my first pair of speakers that I thought had "nice clear trebble." After a year with those miserable things, I thought my ears would bleed every time a symbol scrached its way across those electric hissing pieces of bacon.

I experienced it again second hand when a friend of mine dragged me out to help him pick out a new pair of speakers. He chose the ones with the accented trebble and overly warm bass, while I pointed to a lovely pair of neutral speakers. "Those sound dull," he said, and bought the Cerwin Vegas anyway.

But beyond seeing lay listeners pick unrealistic sounding speakers with peaky curves, I have a deeper issue that I'll bring to the table.

Basically, speakers suck. It doesn't matter if they're electrostatic, electrodynamic, or hybrid. Reproducing audio accurately is no longer a difficult task in the electronics chain, but in a speaker design, every decision becomes a compromise to some extent between imaging, frequency range, frequency response flatness, proper dampening of moving mass, etc. This is where the human element could be coming into play. What if my ears are more sensitive to phase coherence than yours are to a frequency peak at 5,000Hz? Would we still choose the same speaker as having the best fidelity? If my background was drumming, wouldn't I eliminate the poorly dampened woofers from my selection that might not be eliminated by someone else who has much more sensitivity to the woody resonance of a string passage?

That there are so many thousand dollar speakers that sound different seems a testament to the fact that loudspeaker preference is not universal. In fact, the staggering volume of less expensive speakers that are downright distortion boxes suggests that lay listeners are not choosing more accurate speakers over the innacurate ones. I'm not saying these constitute proof by any means, but the market does seem to show a different reality than the one represented by universal taste for accuracy."


The reasoning in these paragraphs readily demonstate the “circle of confusion” scenario that has always existed within the listening environment. Through the years I believe I’ve heard Dr. Toole’s ever-expanding disscertation on loudspeakers, the room, acoustics and psychoacoustics. He always starts off by explaining the “circle of confusion” problem as a step in explaining the efficacy of Harman Multichannel Listening Lab solution.

I was aware when I joined Audioholics that I would need to establish a test methodology that would attempt to mimic the double-blind environment of the MLL in a dealer’s show room. Please refer to
www.audioholics.com/techtips/audioprinciples/loudspeakers/loudspeakersgoodenough2.php

This is part 2 of my Speakers: When is Good Enough, Enough? Series. Sean Olive peer reviewed this article for me before publication. Without the services of Harman’s MLL this is the best test procedure I can think of at this time.
 
gregz

gregz

Full Audioholic
The reasoning in these paragraphs readily demonstate the “circle of confusion” scenario that has always existed within the listening environment...
Yes, I'm aware of the circle of confusion theory, which does exist to some degree in portions of the industry. However, it's GROSSLY overhyped. There are a good many high quality recordings (Chesky, Sheffield Lab, many other recordings by mainstream studios such as RCA, Geffen, etc.) in circulation that sound extremely convincing on quality speakers. Only a buffoon would audition speakers with a Greenday CD.

As for listening rooms, I've heard the good the bad and the ugly. They can be bad, but they can be quite neutral.

I see no connection between the circle of confusion and my points you have dismissed. But I don't believe either of us are likely to convince the other of anything, so I guess we'll have to agree to disagree on this one.

I was aware when I joined Audioholics that I would need to establish a test methodology that would attempt to mimic the double-blind environment of the MLL in a dealer’s show room. Please refer to
http://www.audioholics.com/techtips...goodenough2.php
Double blind tests are awesome! Harmon's revolving setup behind the sheer curtain is indeed impressive. It's a shame they used the same subwoofer for all speakers, though. Thanks for the link, it answered the rest of my questions about the music they used and competing speakers.

...Well, It's been an interesting discussion, though I fear it parallels all too closely an older thread in one of the other discussion rooms a few months ago.

I look forward to your future tests with your double blind setup. On this we agree; double blind is THE way to test. Period.

Regards,
-Greg
 
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Duffinator

Duffinator

Audioholic Field Marshall
gregz said:
Only a buffoon would audition speakers with a Greenday CD.
A buffoon??? And I thought I was just an American Idiot! Hmmmm, isn't it important to audition speakers with music you enjoy and are familiar with regardless of genre or artist?
 
toquemon

toquemon

Full Audioholic
Duffinator said:
A buffoon??? And I thought I was just an American Idiot! Hmmmm, isn't it important to audition speakers with music you enjoy and are familiar with regardless of genre or artist?
Well, yes, but the problem with these recordings is that they have very loud peaks and are artificially supressed and that's why it sounds very compressed, at the same volume level all times; in modern pop/rock recordings the mix is made to sound better in low quality equipments (the kind of super-massmarket you can find in WallMart) and people tend to think that louder is better.

For a serious test i would pick up a different kind of recording.
 
gregz

gregz

Full Audioholic
Duffinator, you are of course correct. Those on a quest to find an accurate speaker should bring carefully selected CDs to audition, while those who don't ever listen to or plan to listen to well recorded acoustic music are better off choosing the speakers that make their favorite music sound good.

In a different thread, I've mentioned that accurate speakers are often very unforgiving of poorly recorded pop/rock music, while the speakers with augmented response curves tend hide the flaws and make the poor recordings sound better.

I have an A/B speaker setup for this very reason. I like music on both sides of the camp, but some of the recordings sound like they were engineered by Hank the Janitor on his break. My forgiving speakers are a 15 year old pair of DCMs that still sound better than most of the cheap stuff in Best Buy these days.

As a side note, I have an EQ in my car that I set in a frown-face pattern to de-pump the music on most FM stations. When I listen to a CD, I turn off the EQ. That's the alternative to A/B speakers for listeing to bad sources on an accurate system.
 
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