The 2011 Richard C. Heyser Memorial Lecture: "Where Did the Negative Frequencies Go?" Case Study 1: Recording

Case Study 1: Recording

Back in 1987, the AES published the anthology pictured above of historic papers on "Stereo." It includes a document (celebrating its 80th anniversary this year) that pretty much defined the whole field of stereo reproduction, including the 45°/45° stereo groove and the moving-magnet stereo cartridge. That document, a 1931 British Patent Application written by the English engineer Alan Dower Blumlein, is worth quoting at length:

"The fundamental object of the invention is to provide a sound recording, reproducing and/or transmission system whereby there is conveyed to the listener a realistic impression that the intelligence is being communicated to him over two acoustic paths in the same manner as he experiences in listening to everyday acoustic intercourse and this object embraces also the idea of conveying to the listener a true directional impression. . . . An observer in the room is listening with two ears, so that echoes reach him with the directional significance which he associates with the music performed in such a room. . . . When the music is reproduced through a single channel the echoes arrive from the same direction as the direct sound so that confusion results. It is a subsidiary object of this invention so to give directional significance to the sounds that when reproduced the echoes are perceived as such."

In other words, if you can record not only a sound but the direction in space it comes from, and can do so for every sound wave making up the soundstage, including all the reflected sound waves (the reverberation or "echoes"), then you will be able to reproduce a facsimile of the original soundstage, accurate in every detail. In addition, because the spatial relationship between the direct and the reflected sounds will be preserved, that reproduced soundstage will give a realistic illusion of depth.

Incidentally, I mentioned earlier Hermann Bondi, one of Hoyle's collaborators on the Static Universe Hypothesis. Like Blumlein, Bondi had worked on the British development of radar in World War II. When I worked in the research lab developing LEDs, in a corner office was a charming elderly gentleman, Dr. Henry Boot. Only years later did I learn that Henry was one of the people who invented the cavity magnetron, which was fundamental to the British development of radar. I suppose you could therefore say that there are just two degrees of separation between me and Alan Dower Blumlein.

The Blumlein Patent Application mentions that, when recording for playback over headphones, the simplest way of carrying out the preservation of the soundstage is to use two microphones spaced as far apart as the average pair of human ears: the "binaural" technique. This, however, makes headphone listening mandatory; until recently, headphones have been about as popular as a head cold for relaxed, social listening. Blumlein was concerned with a system for playback over loudspeakers, and proposed a method of recording directional information as a ratio of amplitude differences between the two signal channels.

The ear/brain, of course, uses more than amplitude information to determine the direction of sound sources. It uses the amplitude difference between the signals reaching the two ears above about 2kHz, but below about 700Hz, it determines direction by looking at the phase difference between the signals; ie, it uses time-of-arrival information. (Both frequencies are proportional to the head size, so there will be a spread among individuals.)

Things get a bit ambiguous between those two frequencies, but there are two other mechanisms also at work: first, the frequency-response modifications due to the shape of the pinnae differ according to the direction of the perceived sound; and second, the head is in continual lateral motion, sharpening up all the mechanisms by introducing second-order (rate-of-change) information. The result is that human beings—and animals—are very good at determining where sounds come from (unless they happen to consist of pure tones in the "forbidden" region between 700 and 2000Hz, which is why birds, for example, use such tones as warning signals).

Blumlein's genius lay in the fact that he realized that the low-frequency phase information can be replaced by corresponding amplitude information. If you have two independent information channels, each feeding its own loudspeaker, then the ratio of the signal amplitudes between those two loudspeakers will define the position of a virtual sound source for a centrally placed listener equidistant from them. For any ratio of the sound levels of the two speakers, this virtual source occupies a dimensionless point somewhere on the line joining their acoustic centers. The continuum of these points, from that represented by maximum-left/zero-right to that represented by zero-left/maximum-right, makes up the conventional stereo image. If there is no reverberant information, then the brain will place the virtual image of the sound source in the plane of the speakers; if there is reverberation recorded with the correct spatial relationship to the corresponding direct sound—that is, if it is "coherent"—then the brain places the virtual image behind the speakers, the exact distance depending on the ratio of recorded direct sound to recorded reverberant sound.

Thus, by recording and playing back just the amplitude information in a two-channel system, we can create a virtual soundstage between and behind the loudspeakers (footnote 6). And if, instead of capturing an original event, we record many individual sounds in mono and assign each one a lateral position in the stereo image with a panpot (along with any added reverberation or echo), when we mix down to stereo, again we have a true amplitude-stereo recording. It is fair to say that 99.99% of all recordings are made in this way. It is so fundamental to how recordings are now made that I doubt if anyone thinks about the fact that it is based on psychoacoustic sleight of hand: the substitution of amplitude ratios for time-of-arrival differences in the midrange and bass.

For many years, I was a hard-line Blumlein purist when it came to classical recording. I was attracted by the theoretical elegance of the M-S technique—a sideways-facing microphone with a cosine or figure-8 pickup pattern is spatially coincident with a forward-facing mike; sum-and-differencing the mike outputs gives you true amplitude stereo—and of two figure-8 microphones horizontally coincident at 90°, each positioned at 45° to the forward direction. Of all the "simple" techniques used to capture live acoustic music, these two, in all their ramifications, are the only ones to produce real stereo imaging from loudspeakers.

I used to dismiss with a snort recordings made with spaced microphones. After all, if the microphones are separated in space by a distance larger than the wavelength of most of the musical sounds—10', say—unless an instrument or voice is exactly halfway between the two microphones, there will be, in addition to the amplitude information, a time delay introduced between the electrical signal that voice or instrument produces in one channel and the signal it produces in the other. Such time information pulls the image of the source farther toward the nearest speaker, resulting in an instability of central imaging and a tendency for sources to "clump" around the speakers. Add to that the fact that the interchannel amplitude differences produced by spaced microphones do not have a linear relationship with the angular directions of the sound sources, and it is hard to see how a pair of spaced microphones can produce any image at all.

Yet . . .

In 1992, we were recording two concerts for Stereophile featuring classical pianist Robert Silverman.

The main pickup was with a single stereo microphone, but I had put up a pair of omnis that I fed to a separate recorder. After the concert, it became apparent that the stereo mike had failed, so I was forced to use the spaced-omni recording for the CD release. Here is a short track from that album, Schubert's Moment Musicaux No.3:

[Play Schubert Moment Musicaux No.3, from Concert CD, Stereophile STPH005-2 (1994)]

There are two things intriguing about this recording. For this lecture, one minute in, I flipped the right channel's polarity. I doubt that anyone noticed—there is so much time disparity between the two channels that it cannot be considered a stereo recording at all; rather, it is two different recordings of the same performance that happen to be played back simultaneously. The second thing is that, despite that theoretical imperfection—for which I was duly castigated on Usenet—the CD sold quite well. People liked the sound.

I wasn't too surprised by that. Theoretically perfect amplitude stereo has served us well, but when I played people some of my classical recordings made in the appropriately purist manner, they often described the sound as "thin" or "cold" or "lacking bloom."

As I said earlier, when people say they like or dislike something, you should take notice. And in this instance, the late Michael Gerzon had discussed the matter in a paper he gave to the London AES Convention in 1987. Specifically, he had postulated that Blumlein's substitution of amplitude for phase differences at low frequencies is inadequate, that people prefer the sound when there is some time-difference information between the channels, presumably because the information their brains use to synthesize a model of the stereo image now has more in common with what they would have heard at the original event.

Gerzon had floated the idea of using two pairs of microphones to capture all the information the brain requires: spaced omnis below 1kHz; coincident figure-8s above, with a crossover between the two. I tried that, with disappointing results. However, after 1992, I used a similar miking technique with which I thought I could get the best of both worlds: the good amplitude stereo from coincident or quasi-coincident mikes, and the lower-frequency bloom from spaced omnis. Both mike pairs were used more or less full-range; the only EQ was a touch of top-octave rolloff on the omnis, and some first-order low-frequency boost on the cardioids to compensate for their premature bass rolloff when used distant from the source.

It was the acquisition of a Sonic Solutions Digital Audio Workstation in 1993 that allowed me to fine-tune this technique, because it became apparent that the two pairs of mikes needed to be time-aligned for the resultant stereo image to lock into place. This time alignment of mikes had been used by Denon and was described in an early 1990s AES convention paper, but I had no way of easily implementing this until I could slide individual tracks backward and forward in time to get the required synchronization.

Since then, I have made all my classical recordings in this manner. Here is a typical example: Minnesotan male-voice choir Cantus singing Eric Whitacre's Lux Aurumque in the glorious acoustic of Sauder Hall, at Goshen College, in Indiana. You can see the two pairs of mikes in this photograph.

Not shown in the photo is a third pair of mikes, omnis on a Jecklin disc, farther away from the singers, which I used in case it turned out that the main pickup was too dry. (When you are on location and the clock is ticking away your money, you cover your bases.)

[Play Cantus: Eric Whitacre, Lux Aurumque (excerpt), from While You Are Alive CD, Cantus CTS-1208 (2008)]

If you listen critically to this recording, you will hear that acoustic objects get a little larger, the farther away they are from the center of the stage. However, their spatial positions in the image are correct.

I tell this tale because it illustrates one of my points: that thinking you are right about something in audio doesn't mean you are right. No matter how much you think you know, there will always be new things that upset your world view. Einstein, for example, would be astonished to find that his "biggest blunder," the Cosmological Constant, turns out to be real—that we now are aware that something completely unknown to science is causing the expansion of the universe to accelerate. Physicists call it "Dark Energy," but that's just scientific shorthand for "We have no idea what it is."



Footnote 6: this creation of a virtual soundstage only works for soundsources to the front of the listener and a two-channel system. However, when the mixing engineer requires a virtual image to be placed to the listener's side in multichannel audio, it fails for the simple reason that we do not have a pair of ears on the front and back of our heads.

COMMENTS
JohnnyR's picture

......blind testing mentioned by a person that doesn't believe in doing them. Aren't they "too difficult" according to yourself? Wait......nevermind just don't answer that because I know it will end up with you Mr Atkinson making some EXCUSE as to why you can't do blind tests for the magazine when it comes to reviewing products. ZzzzzzzzzzZzzzzz.

John Atkinson's picture

JohnnyR wrote:
Sure is a lot of blind testing mentioned by a person that doesn't believe in doing them.

A man sees what he wants to see and disregards the rest, eh? In the 15,000 words of this preprint, there are just a few paragraphs devoted to a discussion of blind testing.

JohnnyR wrote:
Aren't they "too difficult" according to yourself?

As I say, I took part in my first blind test 35 years ago and since then have been involved in well over a 100 such tests, as listener, proctor, or organizer. My opinion on their efficacy and how difficult it is to get valid results and not false negatives - ie reporting that no difference could be heard when a small but real audible difference exists - was formed as the result of that experience.

John Atkinson

Editor, Stereophile

GeorgeHolland's picture

In other words JohnnyR, Mr Atkinson DID find excuses not to use blind testing but found them worthwhile enough to mention them in his Heyser speech funnily enough.

JohnnyR's picture

A. Join a band as a second rate bass player

B. Fail to get a record contract

C.Pretend he's an electrical engineer

D.Get an offer to ruin.....ermm I meant run Stereophile

E. Proceed to ruin........ermmmmm excuse me......run Stereophile like Hitler would.

F. Spend his time talking online instead of actually doing any real work.

G. Make excuss about his busy schedule and why he can't do DBTs

H Profit!!!

Regadude's picture

Johnny makes plywood boxes in his mother's basement, and then claims he is a speaker expert.

Trolls audio websites. 

 

That is all.

ChrisS's picture

JRusskie seems to have become a failed audio (and DBT) expert in one easy step...

 

A. Failed...

dalethorn's picture

Hitler? I don't know whether to laugh or cry.

Ariel Bitran's picture

also, brings both of these to mind:

http://en.wikipedia.org/wiki/Reductio_ad_Hitlerum

http://en.wikipedia.org/wiki/Godwin's_law

ChrisS's picture

There it is, again...

ChrisS's picture

I think a synapse just exploded...

dalethorn's picture

I asked a question of Harman Testing Lab in the Computer Audiophile forum, and post #11 is the answer, which I thought was perfect. i.e., let the testee control the switch, so whatever adjustment time they need they can accomodate.

http://www.computeraudiophile.com/f12-headphones-and-speakers/behind-har...

Other observation: The comments in this Stereophile article about the noise floating free of the recording due apparently to having a higher playback bandwith - that made my day.

On R.C. Heyser: His description of the 1971 Sylmar quake, hearing a low-frequency "tone" prior to the shaking, got him started on comparing earthquakes and woofers and low-frequency playback in rooms, and he got beat up on a lot for those writings. But having been involved with both, those observations of his were like gold in the bank. Saved me lots of money.

Regadude's picture

Aren't you the dude who "tested" the Shure SRH 940 headphones and claimed they were almost as good as the 800HDs from Sennheiser?

I own the SRH940s. I was somewhat willing to believe you, but when I saw that your source was an Ipod, I just flicked your review in the trash.

You chose a 200$ source to test 325$ and 1500$ headphones?  And you believe your results mean something?

 

no

dalethorn's picture

My review of the 940, agreed upon by more than 95 percent of respondents, was vetted with specific music tracks listed in the review and subsequent comments, using ipods alone, ipods with analog amps, and desktop DACs and amps. Some of the naysayers are either impatient or just grumpy and disagreeable, which the comments in this Stereophile article perfectly illustrate.

Regadude's picture

How nice of you to call people who question your methodology grumpy, disagreable, etc. I question your methodology because it makes no sense to test 325$ headphones with an ipod. It makes even less sense to test 1500$ headphones with an ipod...

I actually listened to the Shure SRH940 and HD800 today, using my ipod Nano. You are correct, they both sound almost the same. They both sound like shit!

I know from experience that these headphones really shine with a good source, and especially, proper amplification. As good as the Shure is (I own them), it is no match for the HD800 when both are hooked up to decent equipment.

Your test is like testing the acceleration of a Ferrari and a Prius in your 12' driveway. You won't get much better results from the Ferrari in such a limited distance.

As for the 95% who agree with you, what gear did they use (ipod)? Were those 95% SRH940 owners and fanboys? 

dalethorn's picture

Saying "they both sound like shit" when one of those is a revered $1500 headphone of great pedigree and popularity among actual audiophiles is telling of your judgement. I would suggest taking a deep breath, pick a headphone and some music tracks you like, then tune out the matrix and just enjoy your music. You'll be less grumpy that way.

Regadude's picture

Don't try and hide behind my words! They both sound like shit through an ipod! What a weasel you are. I did not say the 800HD sounded like shit... BUT IT SOUNDED LIKE SHIT THROUGH AN IPOD. You rigged your test, Dale. 

Again, you use insults...

 

dalethorn's picture

A long time ago one person on a big audio site challenged people like you to be more specific instead of throwing words like s**t around. There were just two persons who offered test tracks with which to compare those headphones, but everyone else (like you) just threw out expletives, and a couple members even made serious threats. Now I have over 30 years experience comparing headphones like the Stax and Sennheiser series, and quite a bit of time invested with the Audio Engineering Society as well as reading Stereophile magazine, so even if nobody in the world were to agree with my conclusions, I'm certainly qualified to test and evaluate these devices. I'd suggest you refrain from purely ranting with words like s**t and offer specific testable facts, or just go away.

This article may help you:

http://dalethorn.com/Headphone_Ipod_Versus_Amp.txt

dalethorn's picture

BTW, and speaking of Prius and Ferrari, you may be one of the better off who don't mind paying $1500 for a headphone and then shelling out $2000 for a headphone amp. But let's pretend for a moment that you have to pinch pennies to get those luxurious goods, so when you finally have them you really appreciate what you have. In this latter case, were you to stumble across an ipod touch or iphone of recent manufacture, with the new Earpods ($29 purchased variety only) being driven by the Dirac DSP player, and had an opportunity to listen at length, it might make you ill to realize what you got for your $3500.

Regadude's picture

My headphone amp is a whopping 400$ (CI Audio VHP 2).

I do pinch pennies. The VHP 2 and the Shure 940 are mine.The Sennsheiser 800HD I borrowed from a friend.

Stop trying to cloud the issue with non relavant issues.

Regadude's picture

How about we let Stereophile test both headphones! First through an ipod, then with decent equipment!

Both headphones sound similar through an ipod.

Plug them into a receiver, they sound less like shit.

Plug them into a decent headphone amp, and they both sound MUCH BETTER. BUT the Sennsheiser pulls away and wipes the floor with the Shure.

Buy yourself a CI Audio headphone amp (the one I use), or any other decent headphone amp Dale... Before buying a 2500$ DAC to install on an ipod.

DUH...........................

GeorgeHolland's picture

The continuing saga of ChrisS being a troll and all around noncontributing poster. Classy act there ChrisS.

Mostly what I got from Mr Atkinson's article was the amount of photos of himself rather than Mr Heyser. I suppose a memorial lecture should be all about the presenter and how he sees fit to turn it into reasons why Stereophile does what it does regarding testing and the lack there of.

"Yes, what you think you are hearing might by dismissed as being imagination, but as the ghost of Professor Dumbledore says in Harry Potter and the Deathly Hallows, "Of course it's all happening in your head, Harry Potter, but why on earth should that mean that it is not real?"

Oh I see now. Stereophile's philosophy is based upon a ficticious Harry Potter character who spouts that what we hear is real.I'll be sure to let those people being treated for such voices in their heads that all is well and medication is not necessary.

"Footnote 2: For a long time, I've felt that the difference between an "objectivist" and a "subjectivist" is that the latter has had, at one time in his or her life, a mentor who could show them what to listen for. Raymond was just one of the many from whom I learned what to listen for."

Well if only that was true. Your readers tend to all be subjectivsts who aren't trained what to listen to but blindly ( I made a pun there since blind testing is not wanted at Stereophile) believe whatever they think they hear as the truth when in fact measuremnts will show that either they heard nothing related to the measurements or perhaps it's Dumbledore once more in their heads, make believe or wishful hearing.

All in all I found your presentation 90% about yourself and Stereophile and reasons why you defend subjective listening and gloss over things like cables and doing serous testing and throwing in various quotes and ambiguous stories barely related to the subect you were supposed to be talking about, unless that subject was muddling the understanding of Stereophile and telling everyone your own personal history instead of Mr Heyser's.

"Third, one well-known skeptic sitting in the audience tonight criticized my abstract a few weeks back on the grounds that I am just offering "hypotheses about stuff that might be just to stir the pot, while offering no real explanations."

Class act there Mr Atkinson, speak out and criticise someone you don't like or agree with in the audience who then has no opportunity to speak up and address the audience themselves. Very childish and immature.I already see how you do the same on here. "My way or the highway"

JohnnyR is once more sadly correct, Blind testing is not and wil not be used by Stereophile. Just because you Mr Atkinson, know how to push a few buttons to measure speakers, does not make you even close to the same league as Mr Heyser was. He furthered the cause of objectivity and made Audo magazine the best audio magizine there ever was. The Audio Critic is a very close second. Mr Aczel used to be one of the worst subjectivists around untill he admitted to being such and saw the light and spoke out against foolish subjective reviews. Testing will always be the most important part of audio magazines. Simply letting reviewers spout off about "blacker backgrounds" "lifted veils" or other such nonsense belittles both the reader and the so called reviewer not to mention the product under "test". Truth in testing is what Mr Heyser strove for not some silly review about rainbow foil, magic bowls or pebbles.

John Atkinson's picture

George Holland wrote:
Mostly what I got from Mr Atkinson's article was the amount of photos of himself rather than Mr Heyser. I suppose a memorial lecture should be all about the presenter and how he sees fit to turn it into reasons why Stereophile does what it does regarding testing and the lack there of. I found your presentation 90% about yourself and Stereophile...throwing in various quotes and ambiguous stories barely related to the subect you were supposed to be talking about, unless that subject was muddling the understanding of Stereophile and telling everyone your own personal history instead of Mr Heyser's.

You have misunderstood the nature of the lecture, GeorgeHolland. The Richard C. Heyser Memorial Lectures are not intended to be _about_ Dick Heyser but instead are offered to honor his memory. The invitation for me to be the October 2011 lecturer clearly stated that I was free to choose any subject I felt appropriate; my triple career as a musician/audio engineer/audio editor and the conclusions I have formed as a result of my 4 decades' experience in those careers were felt by the AES Technical Council members to be an eminently suitable subject. 

George Holland wrote:
Class act there Mr Atkinson, speak out and criticise someone you don't like or agree with in the audience who then has no opportunity to speak up and address the audience themselves. Very childish and immature.

The skeptic in question had emailed me before the lecture to let me know he would be in the audience and would take an active part in the anticipated Q&A session. I included this mention in the preprint to give him the necessary opening. As it turned out, he didn't attend, but I saw no reason to delete the point he made.

George Holland wrote:
Just because you Mr Atkinson, know how to push a few buttons to measure speakers, does not make you even close to the same league as Mr Heyser was.

I agree. As you can tell from my discussions of Dick Heyser's writing and thoughts in the preprint, I have an enormous amount of respect for what he achieved. I have never claimed to be his equal, nor would I. But again I must emphasize that the AES Heyser lectures are not intended to be _about_ Dick Heyser. That is your misunderstanding, I am afraid.

John Atkinson

Editor, Stereophile

Rolli666's picture

I am not sure as to why a person would even want to respond to these posts. Some problems really are better ignored as to invoke the spirit of go away.  I for one appreciated this lecture for what it is thank you.

John Atkinson's picture

Rolli666 wrote:
I for one appreciated this lecture for what it is thank you.

Appreciate your comment. It is rare that a magazine writer has the opportunity to gather all his thoughts in one place and I owe a debt of thanks to the Audio Engineering Society for inviting me to do so.

John Atkinson

Editor, Stereophile

 

ChrisS's picture

Whoa! There goes another synapse! Now they're both brain dead... I duelled extensively with JRusskie re: blind testing on the Forums and I daresay, he shot himself many times with his own arguments.

Saga? Can't wait for the movie version!

Sorry, Ariel... I'll try not to let it happen again.

Dunadan's picture

...which is a valuable insight, I think, from this article that Mr. Atkinson has generously preprinted. His stories--which, though I am not a longtime reader, I presume also reflect the history of Stereophile--mirror the tensions found in the philosophy of science between "reality" and "perception", and the question of whether our observations are truly disinterested or if our minds shape how and what we see (or hear). And, really, what exactly does a blind test resolve? That the reviewer likes one piece of equipment over another, presumably without factoring in aesthetics or cost? But "liking" one thing better than another is still a subjective judgment, and who's to say YOU would share that judgment? Never mind the problem of translating sounds heard by another into words on the magazine's page and then back again into the sounds heard by the reader when he or she auditions the gear. Or the issue of whether sound quality can be adequately described by a series of measurements, any more than colour can be described strictly in terms of wavelength, or consciousness in terms of vibrating atoms in your brain. That's not to say these things aren't significant, but to say that they add up to the sum of our human experience is absurd.

Thanks for a reflective and enjoyable article (at least in my mind).

GeorgeHolland's picture

The purpose of blind testing is soley to see if you can hear a difference between two units. After all the subjective rants of "oh this lifted several veils of crud from the liquid sound" or "I heard a definite improvement" I find it sad that Sterophile keeps saying that DBT or even SBT are not a valid way to test those claims. Either you can hear a difference or you can't yet those that claim they do shy away from proving that fact with a blind test. Afaid they might be shown to be wrong is my opinion, so Stereophile allows them to go merrily along in their own self delusions while spending way too much money on sham products.

ChrisS's picture

In a properly set up DBT, let's say for two amplifiers, what exactly will the listener be listening for?

 

(And what if the lamb heard a difference, but not the shepherd boy?)

GeorgeHolland's picture

Are you seriously so dense that you can't figure it out for yourself? Perhaps that's why you depend upon Stereophile to tell you what to buy?

http://home.provide.net/~djcarlst/abx.htm

http://www.matrixhifi.com/contenedor_ppec_eng.htm

Read and learn.

ChrisS's picture

So Georgie,

If the lamb can hear that Amp A can make the test system sing in a range of 10hz-60khz, but the shepherd boy can't hear in that range so can't tell the difference between Amp A and Amp B, which amp should the shepherd boy buy?

GeorgeHolland's picture

No you may address me as George or Mr Holland. Georie is an attempt at making fun but then again that's about all you know to do anyway.

Please ask a relevant question or just shut it.

The lamb would first have to prove they can hear a difference with a dbt

The shepard can buy whatever he wants.

The big bad wolf tried to convince both that the expensive boutique amp was the one to buy

They told him to shove it and bought a less expensive but well built amp and they all lived happily ever after except for Mr Big Bad who soon folded his shop due to no sales.

ChrisS's picture

So Georgie,

Let's make this question relevant....

Let's say we're testing two amplifiers with two listeners. The first listener is an 18 year old young lady who is trained in classical piano at a Grade 10 music conservatory level. She can hear that Amp A has an excellent range 16hz-40khz through the test system, but even though Amp B doesn't have the same range, she likes the "sound" of it better.  The second listener is the shepherd boy who's grown up now. He's 54 years old, likes big band jazz, but his hearing has been damaged by working with heavy machinery without hearing protection. He can't hear a difference between the two amps.

 

Which amplifier should the ex-shepherd buy?

GeorgeHolland's picture

The 18 year old can hear to 40KHz?  Were her parents bats?

"Like" doesn't have anything to do with blind testing. You don't pick which one you "like" you see if you can tell WHICH amp is playing. You don't even know how a dbt test is run I can see already.

 Who cares which amp they buy?  Maybe the people selling them do but that is completly irrevelant to dbt. You have no clue as to what blind testing is all about.

ChrisS's picture

Georgie,

Are you a real person or a computer generated figment from JRusskie's russian clone of an old IBM PC? Do you know anyone with normal hearing? Do you know how real people shop or do you isolate yourself in the sanctuary of your closed mind and order everything on-line after reading extensive reviews in Consumer Reports?

ChrisS's picture

You call those proper Double Blind studies?

GeorgeHolland's picture

Oh so you are an expert on double or single blind studies. The ABX system is a proven dbt way to do things. Just because the results have you so upset, you claim the people doing the testing are doing it wrong? Laughable. Tell me some more jokes.

ChrisS's picture

...Swinging down the street so fancy-free..."

 

In fact, Georgie, my major(s) for my undergraduate degree were in Developmental Psychology (including Perception) and Statistics (including Research Methodology). So yes, the set up and methodology shown in those links are crap and the results are laughable...

ChrisS's picture

Get thee to a local college and enroll in a first year research methodology course. Have fun learning!

GeorgeHolland's picture

Either address me as George or STFU you stupid little boy. I think you majored in being a twit and smart ass. Who can take anything you say as serious? Grow the fuck up already. You act out like a lil boy with the IQ of a rock.

Go tell the people who make the ABX test system what you just said and see how they laugh you out of the room. You bring nothing to this discussion other than what you don't agree with , with zero facts to back up your claims. Come on show us all how the ABX test methods aren't any good or why the blind testing done in the othe link was faulty. Better yet tell Harman Kardon that their blind testing techniques are faulty and not worth doing.

ChrisS's picture

Georgie,

You must be running out of neurons if you don't trust your own eyes and ears. Yes, the facts are out there.

JohnnyR's picture

.is what SBT and DBT are all about. Using your eyes to test audio products? Well yes I can SEE that YOU would have to look so you would know which one is "better".

ChrisS's picture

Whose ears? Why?

John Atkinson's picture

GeorgeHolland wrote:
I find it sad that Stereophile keeps saying that DBT or even SBT are not a valid way to test those claims.

Please do not put words in my mouth. That is not what I have said. What I _have_ written is that to design a blind test that limits the variables to just that which you are interrsted in and that produces valid results when there is a small but real audible difference is complicated and time-consuming. The literature is full of poorly designed and performed blind tests that have been proclaimed by audio skeptics as "proving" that there are no audible differences. Such people demonstrate both their ignorance of the Scientfiic Method and their unquesitoning faith in "Scientism."

John Atkinson

Editor, Stereophile

GeorgeHolland's picture

JohnnyR was right more EXCUSES.

It's pretty simple Mr Atkinson but then having the will or gumption to put a dbt into the line of testing is the first thing you have to have,

You obviously don't have that or just don't care so it's a moot point anyways.

JohnnyR's picture

.nor ever will when money is involved.

dalethorn's picture

I would hate to see magazines and websites like Stereophile become intimidated by naysayers who demand "proof" of everything they say, in advance or after the fact. There's a lot of that in mainstream media, due no doubt to controversial topics and false information being fed to reporters. But come on, people - this isn't a mainstream news outfit reporting life or death stories. We have here an incredibly rich article full of facts that can be researched and questioned with references that are well established over time. Instead we have people questioning the author's motives or his pursuit of truth? I think people who are looking for "The truth" should be looking in a religious forum, not a hi-fi forum. There's very little you can "prove" on these topics - the value here is the very informed opinion that costs you nothing.

Ariel Bitran's picture

nice comment Dale. as an attendee of this lecture, i can tell you it was surely enlightening.

GeorgeHolland's picture

I think you have it all backwards there friend.....

"I think people who are looking for "The truth" should be looking in a religious forum, not a hi-fi forum. There's very little you can "prove" on these topics - the value here is the very informed opinion that costs you nothing."

Religion is based upon belief and subjectivists cling to their belief, they don't go looking for proof or the scientific method. No you can't prove very much when the reviewers use subjective say so instead of actually measuring the units. Opinons are a dime a dozen or even less than that and worth next to nothing. Just look at all the opinions here.

dalethorn's picture

No, George, you don't get it. You're still stuck in religion, looking for proof of something. Here you get 'information' only, and if you want 'proof' of something, you have to do the work in proving it to yourself. What *you* believe, outside of yourself, is purely opinion. Perhaps all these people looking for truth or proof are just lazy, and trying to intimidate others into doing the work for them. Like bullies.

JohnnyR's picture

......the facts there pal. Your "arguement" is FLAT.  The only "info" Stereophile shows us is what the WANT to show us. Cables, power cords, magic bowls are off the list of even testing them in anyway what-so-ever. The reason? Ohhhhh we really don't know how to test those duhhhhh. How lame an EXCUSE is that?  Stereophile is SUPPOSED to be a magazine for information NOT excuses.

"Perhaps all these people looking for truth or proof are just lazy, and trying to intimidate others into doing the work for them. Like bullies."

 BWAHAHAHAHAH!!! that has to be on my "Top 10 WTF Things of 2012"

 You DIDN'T just say that did you???? So let me get this straight, Stereophiles job as you see it is to just fling out "say so" and it's up to the readers to wade through the muck and mire of those reviews to try and grasp one little bit of truth? Yeah right, you must really love it then because they rarely show any truth at all.

Ariel Bitran's picture

why is it so hard to accept that double-blind listening tests are difficult to achieve as JA has explained in his lecture?

the fact that our existences are commandeered by individual perception based on thousands of variables makes it very easy for me to understand, just as how one person may enjoy spicy foods but not grapefruit or where some may hear too much bass and others not enough. so many VARIABLES!!! culture, upbringing, what sounds you are surrounded by, traffic signals, your genetic structure, your actual physical position when listening. perception is a learned skill that we do not choose to accept, it just happens and it is different for every single person.

i think THESE are the sort of differences between individuals that make DBT difficult: everyone hears differently. there is no absolute sound.

the best example of how an ear and sonic preference can change is in the study of language and sounds. the chinese language has a completely different set of sounds to that of the english language, thus their speaking intonation, laughter, and music reflect their cultural and sonic inclinations. eastern and western and andean and greek and celtic and ... and ... all use completely different scales based on their preferences of sound learned over time through language and their environments.

Thus, i often wonder do hi-fi listeners across the globe prefer different sounding systems based on their installed sonic memory? or is there a constant in terms of preference across the globe? probably not. or even more interestingly, can one find similarities in preferences in sound based on linguistic sounds of an individual region? are the frequencies accented in the german language more easily noticed by a german in his hi-fi? DBTs are a waste of time. instead of focusing why not, it is much more fun to focus on the why.

the heart of all of this lies within JA's question: where do the negative frequencies go? there are aspects to our perception of sound that simply cannot be measured because they are based on individual perception which is different for every single one of us.

GeorgeHolland's picture

If blind testing is so difficult then how did the people that I linked to manage to do so?  Harman Kardon does blind testing at the drop of a hat. Go ask them how they do it so easily. Mr Atkinson's refusal to do so is simply an excuse as to not have to bring up why cables, power cords and other snake oil is indeed snake oil. He can merrily go along his way as he has for years now ignoring such products and letting his reviewers say whatever BS they want about the sham products and not have to worry one bit. He just doesn't care is the bottom line.

ChrisS's picture

Georgie Porgie,

That you cite these links as authoritative sources indicates the level of your understanding of testing methodology.

JohnnyR's picture

......nothing to back up whatever it is you are trying to say but it is amusing.

ChrisS's picture

Research methodology courses are taught in colleges and universities all over the world, even Russia...

Let us know when you and Georgie take one.

JohnnyR's picture

Nothing to cite other than your own wandering silly posts? Thought so.

Regadude's picture

Well little Johnny, at least Chris is A REAL psychologist. He's not a, you know, a hobbyist like yourself...

JohnnyR's picture

........credentials from ChrisSy just say so. Oh lets see I think I'll be a nuclear scientist now just because I say I am on the forums. There now it's a done deal. Besides how he acts out is more like a 3 year old than an adult. Some professional he is and tell us all again just what your expertise is? Trolling perhaps?

Regadude's picture

...credentials from Johnny the hobbyist speaker designer. Let's see some pictures of your Johnny brand speakers! Post some pics, or provide a link to a site where we can see these speakers of yours.

I demand to see these speakers of yours! 

ChrisS's picture

If JRusskie has a misguided and limited understanding of DBT, and....

Georgie has a misguided and limited understanding of DBT, then....

Are JRusskie and Georgie one and the same person?

Has anyone seen them in the same room together? Hmmmm.

Please, one of you (I guess it doesn't matter which...) ask Harman Kardon how they do their DBT's and how they use the results.

Thank you.

JohnnyR's picture

I haven't seen one iota of explanation from yourself yet as to why both of us and Harman Kardon and the other links George posted to are wrong. Still waiting ChrisSy.

ChrisS's picture

Has HK hired you guys as DBT consultants?

 

Hey JRusskie,

Can you answer this one?

If A=B and C=B, then A=?

If you pass the test, then perhaps someone will hire you... But you and Georgie might have to fight over the job.

JohnnyR's picture

"i think THESE are the sort of differences between individuals that make DBT difficult: everyone hears differently. there is no absolute sound."

The sole purpose of DBT is to see if the person listening can distinguish between A and B. If they can't then for all practical purposes there is no difference in the sound from A and B. You and ChrisSy seem to think it's all about what the person "likes". It's a straight forward test method and "likes" has nothing to do with it.

Please explain to us all how Harman Kardon manages to use DBT all the time and do it well? I will be awaiting your reply Ariel.

ChrisS's picture

So every household has a Harman Kardon product? And you and Georgie have living rooms that look like anechoic chambers? No fireplaces, of course....

ChrisS's picture

Hearing a difference between a Harman Kardon product and another product in a anechoic chamber means what to you, Georgie and JRusskie?

Do you know that Ford makes the best trucks in the world?

ChrisS's picture

Are you sure I didn't say 'licks". You know maybe tasting an audio product will yield just as useful results in a DBT.

ChrisS's picture

JRusskie,

Now run out to your nearest Boris' Convenience store and get yourself a can each of Pepsi (do you even have Pepsi in the Former-USSR?) and Coca-Cola and set up your own Pepsi (or whatever passes for cola in Russia) Challenge.

Wiki has a nice explanation of how to do a DBT...

Once you've done your very own Peps(k)i Challenge, please send us your conclusion. We're curious...

The next step now is to get everyone in your subsidized housing project to participate in your Pepski Challenge.

Gather up that data, compare it your own conclusion and let us know how useful that information is.

I'm sure you'll enjoy the challenge of your doing your very own DBT's! (You won't even have to ask Harman Kardon to use their anechoic chamber!)

John Atkinson's picture

JohnnyR wrote:
The sole purpose of DBT is to see if the person listening can distinguish between A and B. If they can't then for all practical purposes there is no difference in the sound from A and B.

And that's the problem with these tests. If a formal blind test gives results that are indistinguishable from what would be given by chance, formal statistical analysis tells us that this result does _not_ "prove" there was no difference in the stimulus being tested, only that if there _was_ a difference, it was _not_ detectable under the conditions of the test. No more general conclusion can be drawn from the results. And as I have said, it is very difficult to arrange so that those conditions don't themselves become interfering variables. Even the fact that it is a test at all can be an interfering variable, as I explain in this lecture preprint.

JohnnyR wrote:
Please explain to us all how Harman Kardon manages to use DBT all the time and do it well?

I have visited Harman's facility in Northridge and their blind testing set-up is impressive. They have worked hard to eliminate interfering variables and their testing is time- and resource-consuming and painstaking. Even so, they have to make compromises. Blind testing of loudspeakers, for example, is almots always performed in mono. And despite the rigor of their testing, you still have anomalous results, like the Mark Levinson No.53 amplifier, which was designed with such testing but fared poorly in the Stereophile review.

While formal blind tests are prone to false negative results - not detecting a difference when one exists - sighted listening is prone to false positives, ie, it detects a difference when none exists or perhaps exaggerates the degree of difference. As neither methodology is perfect, we go with the one that is manageable with our resources. We therefore offer our opinions for readers to reject or accept in the context of their own experience and I believe Stereophile does  a better job of that than any other review magazine or webzine.

If you are uncomfortable with that policy, then you should not read the magazine. And if I remember correctly, JohnnyR, you admitted in earlier discussions on this sute that you neither subscribe to Stereophile, nor do you buy the magazine on the newsstand. So why should anyone pay attention to your opinions on how the magazine conducts itself?

John Atkinson

Editor, Stereophile

JohnnyR's picture

So you are saying that if in a DBT the listeners could NOT tell a difference between two amps using music of their own choice then that doesn't prove the amps sound alike?  Funny stuff there Atkinson. For one who thinks you should trust your ears to evaluate components you just bashed the ONE single TRUE way to test by USING YOUR OWN EARS in a DBT.

"And that's the problem with these tests. If a formal blind test gives results that are indistinguishable from what would be given by chance, formal statistical analysis tells us that this result does _not_ "prove" there was no difference in the stimulus being tested, only that if there _was_ a difference, it was _not_ detectable under the conditions of the test."

Your own words are saying that "if there was a difference it was not detectable under the conditions of the test"........oh you mean like letting the listener use the music of their own choice and switch back and forth endless times between two amps and then guess wrongly enough times so that they can't tell which one was which? LMAO if that's not proof that both amps sound alike then what sort of test WOULD prove that they do?  Come on Atkinson you just don't like DBTs because they would show up so many components that people think sound "oh so better than the rest"

Opinions from you and your reviewers are the Gospel now folks. No need to test anything really just trust good ol'JA and his flunkies. Yay.

"If you are uncomfortable with that policy, then you should not read the magazine. And if I remember correctly, JohnnyR, you admitted in earlier discussions on this sute that you neither subscribe to Stereophile, nor do you buy the magazine on the newsstand. So why should anyone pay attention to your opinions on how the magazine conducts itself?"

Oh just maybe because  a lot of people care for this little thing called the TRUTH? When magazines like your's take liberties with the truth by having shoddy reviews instead of in depth testing, then it's everyone's and anyone's responsibility to speak up when crappy falsehoods are published and the readers are supposed to take it all on faith. That's why. I for one do not take your opinions on anything audio related as worthwhile at all for the simple reasons that you show so much promise when you measure speakers but fail to even bother with the snakeoli products that you let slide under the radar yet let your reviewers give them glowing reviews sans any testing what so ever. Maybe that's the sighted listening bias you just spoke about yet you fail to even try with those type of products to get to the real TRUTH.

ChrisS's picture

JRusskie,

If you like Harman Kardon marketing, but you're not sure if Ford makes the best trucks in the world, then get yourself an F-150 and whatever truck you used to rumble across Afghanistan with, do your DBT (just like  the Pepski Challenge) and let us know what you come up with...

You are marketing TRUTH now? How pure is it?

I know some construction workers who might be interested...

ChrisS's picture

JRusskie, Just looking at your response to John's post and comparing word-for-word what John wrote and what you think he says, there's such a huge world of difference!! There's a war in your head!

[Flame deleted by John Atkinson].

GeorgeHolland's picture

"Even so, they have to make compromises. Blind testing of loudspeakers, for example, is almots always performed in mono."

Well Mr Atkinson the reasoning behind testing speakers in mono is to eliminate the dreaded comb filter affect that would otherwise show up if a stereo pair were auditioned and the listener moved their head even a couple of inces. I'm surprised you didn't mention that fact but then again you think DBTs are hard to do, so if you don't know how to do them then indeed they are hard to do. *Chuckle*  Any DBT done should be auditoned is such a manner. The rest of your "excuses" for not doing them is the same old same old from you, nothing surprising there.

ChrisS's picture

So Georgie Porgie,

Let's say JRusskie is DBT'ing a $1500 speaker and a $500 speaker and can't hear a difference, and you are DBT'ing a $4500 speaker and a $4000 speaker and you happen to have enough working neurons to hear a difference... Which set of speakers should the ex-shepherd construction worker buy?

John Atkinson's picture

GeorgeHolland wrote:
John Atkinson wrote:
Even so, they have to make compromises. Blind testing of loudspeakers, for example, is almost always performed in mono.

Well Mr Atkinson the reasoning behind testing speakers in mono is to eliminate the dreaded comb filter affect that would otherwise show up if a stereo pair were auditioned and the listener moved their head even a couple of [inches].

That is a consideration, of course, but in my opinion a minor one. As I had understood from Floyd Toole back in the day, the additional complexity required  of  Harman's physical speaker shuffling apparatus to do blind speaker testing in stereo was not justified by the results, ie, they felt that the stereo performance could be predicted from the mono results.

I don't agree with that, but more importantly, this illustrates the thesis offered in my lecture, that when you move the testing situation a step away from how the product is going to be used, you can't be sure that the assumptions you make haven't invalidated the test. As I write in the abstract to the lecture, "perhaps some of things we discard as audio engineers bear further examination when it comes to the perception of music."

BTW, I am still waiting for you to acknowledge that the criticism you made of my lecture, that it was not about Richard Heyser, was incorrect.

John Atkinson

Editor, Stereophile

GeorgeHolland's picture

More excuses?  I see what Johnny meant. You are never wrong. I am pretty sure Haram Kardon knows what they are doing. Please address any criticisms to them not me.

I am afraid that comb filtering IS a big deal. That would explain why cables "sound" different. It's not the cable but the listener changing where their head is between "testing"

You will be waiting a long time for any ackowledgement about your "lecture". Stop being the primadonna already.

Regadude's picture

Georgie wrote:

"Stop being the primadonna already."

Look in the mirror and repeat those words!!!! laugh

ChrisS's picture

So how does one differentiate speakers that sound differently, amplifiers that sound differently, pre-amps, turntables, tonearms, cartridges, DAC's, etc., if a turn of one's head makes that much difference?

Where's your reliability, Georgie? Doesn't science depend on reliability?

JohnnyR's picture

I can see what George is up against in here with Tweedle Dum and Tweedle Dee tag teaming and showing their ignorance.

http://www.ethanwiner.com/believe.html

Golly look what he meant.I think Ethan was banned from here ages ago for showing up Fearless Leader and his cronies and out right showing how REAL science works. BWAHAHAHAHAHAH loser boys.

Regadude's picture
John Atkinson's picture

Quote:
http://www.audioholics.com/news/editorials/diy-loudspeakers

Just bookmarking the link for future reference.

John Atkinson

Editor, Stereophile

JohnnyR's picture

......when you start doing a single DBT or even a SBT then you can talk about the "truth". Have you EVER designed and built your own speakers? Nahhhhhhhh you are too lazy or too "busy". Still finding plenty of time though to post online all the time though strangely enough.cheekyTill then you aren't an engineer so take your own advice and don't comment on speaker design anymore.

If you are going to save the link then please also save this link where discussion about it unfolded.

http://forums.audioholics.com/forums/loudspeakers/83412-diy-loudspeakers...

As you can see the original post was just one of many OPINIONS about the topic that is if you bother to read it at all. There are various OPINIONS about the topic and notice just how many of the so called "hobbyists" ended up being professional speaker builders. If you just pick and choose certain OPINIONS from the thread then you are guilty of leaving out facts.

For starters read the sixth post down by Jinjuku regarding Jeff's post that pretty much sums up where DIY has progressed.

ChrisS's picture

Not real science either...

GeorgeHolland's picture

Frick and Frack strike again. Regadude and ChrisS always come up with strawman replies and ignore the links posted."Not real science "? How pompus can you get? Mr Winer measured the effects of comb filtering, what did you measure ChrisS the length of your nose when you typed that reply? You dismiss anything people link to yet show us nothing in return. Regadude, posting opinions isn't real science just so you both understand. Now run along lil boys and study real hard, maybe in another 20 years you might be able to hold your own in a discussion.

ChrisS's picture

Has Winer's results been verified?

Did you know that Harman Kardon makes the best audio products in the world? And Ford makes the best trucks, right?

JohnnyR's picture

Or is that above your abilities like thinking?

Go ahead, put on a pink or white noise source and move your head about and tell me the sound doesn't change. You won't bother so forget it ChrisSy.laugh

ChrisS's picture

When moving a microphone while recording a person's voice, the sound changes. Did the voice change?

GeorgeHolland's picture

You never answer a question , you just put forth silly questions of your own. That's what people do when they don't know or are scared to try.

Moving a microphone while recording a person's voice? If that's how you do things then no wonder you don't know what Johnny was talking about. Yes the sound changes as recorded by the microphone so what?  Genius.angle

ChrisS's picture

I'll answer you this one... You and JRusskie always answer your own questions that you pose to everyone in these discussions. There's no need to provide any answer to you. As well, your attitudes and limited knowledge of the application of research methodology make civil and thoughtful discourse impossible.

So my questions to you and JRusskie are formed to reveal how each of you think whenever you provide a response.

You provide enough information for me to say that I find the "best" use of my time in these discussions is to make fun of you and JRusskie.

Ariel Bitran's picture

makes some sense of the whole darn thing.

Regadude's picture

The only duo that strikes here George, is you and Johnny. You both STRIKE OUT!

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