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208.58.2.83
In Reply to: Re: Lotsa reasons posted by KlausR. on May 6, 2007 at 07:33:20:
...are the numbers? The analyses? You're a "scientific" type; please explain to us dunces.However, all the evidence you may need is in the very book described in your referenced article; of the some eighty instances of "absolute polarity" appearing in the entire audio and acoustical literature (in English), academic and otherwise, through 1987, all but one were positive as to its audibility.
clark
Follow Ups:
As I'm browsing what I have about this polarity issue, I come across this :
"When you reverse connections at a loudspeaker, yes you reverse audio signal polarity. But you also reverse the direction the audio signal is applied to wire in the loudspeaker and to capacitors, inductors and resistors in the crossover. When you reverse wires, capacitors, resistors and inductors in the audio signal path, the result is an audible change in the sound."If this is correct, and I can't see any reason why it isn't, all experiments done hitherto are flawed from the outset. If you further consider the (asymmetric) distortion issue (LP playback, speakers)you have another basic flaw.
Now YOU explain.
Klaus
You avoided answering my question. What's the scientific basis for "convincing"? Surely it can't come down to just your own opinion? Give us some numbers, some analyses.clark
There was quite a long thread many moons ago on these pages, all that could be said has been said then. Nothing more to add.The purpose if THIS thread, just in case you didn't notice, was not to discuss audibility of polarity but to discuss why there should be a standard in recording industry when the overwhelming majority of home speakers messes it up.
Where can one read your rebuttal?
Klaus
...I did indeed devote several paragraphs to the situation. "Where can one read your rebuttal?" You have the tools already: Google "doug blackburn" "clark johnsen". Result below.We still don't know your scientific basis for declaring evidence "convincing". Perhaps you shouldn't talk like that if you want to maintain your, ah, reputation here -- or at the very least stand up for your pronunciamento.
clark
...I'm one to complain to moderators; I prefer having your rudeness on record.Besides which, clearly, you have not read the referenced text -- which at the time was lauded by Stereophile (JA), Audio Magazine (Ed Long), Speaker Builder, 21st Century Science & Technology and many others. The text was not "highly contested", just the opposite.
Get the facts straight before your next outburst of envious contumely.
clark
Let's see:"The main theme of this book deals with absolute polarity, a very important aspect of sound reproduction which has been much neglected."
"Near the end, Johnsen states his major premise: 'Only one concept must be grasped: Electricity can reverse its phase, while music cannot.' The problem with this statement, from my viewpoint, is that the author uses the word "phase" instead of "polarity" to describe what can happen to the electrical signal. He does this elsewhere in the book also, which can tend to confuse the very issue he is trying to clarify. The problem is one of terminology, not of substance."
"Although I agree with the major premise of the book -that absolute polarity is extremely important- I must say that pages 67 to 74 are full of erroneous and misleading information about loudspeakers. Unfortunately, it is a case of trying to explain, in technical terms, why some loudspeakers behave the way they do, without having the expertise required to do do. Since the author is no loudspeaker system designer and quotes the writings of others who are not designers either, perhaps this excusable."
"The last two chapter are an odd mixture and, therefore, difficult to describe. There is an interesting list of recordings, each marked with the author's own polarity convention, which is relative to the first record for which he determined the correct polarity. It would have been better if he had determined the absolute polarity of his own system before he began marking his collection. As it is, his "normal" and "reverse" designations might be reversed! Oh well, at least they are consistent, which ir more than the whole audio industry can say for itself."
"The tone of Johsen's book is rather quixotic, and I don't think the author will mind me saying so. Rahter, I suspect he will take this a the compliment it is meant to be. This is a potentially controversial book, and it is quite clear the author intends it to be so. I found it fun to read."
Johnsen's book had been reviewed in a negative manner by Pr. Dan Shanefield in Boston Audio Society Speaker. Passage from Clark's reply to the review: "A negative review [Editor's note: two, actually, as well as a generally positive (Ithought) one] of my first and only book recently appeared herein."
Klaus
"I propose that from this point forward the entire audio industry take a basic step which is capable of improving the quality of the listening experience without adding any cost to that product."Care to guess, what that step may be?
"With constant improvement in audio systems we have now reached the state where many persons can readily perceive the coloration caused by improper polarity in the reproduced sound... Aware of the distinct audibility of polarity since 1974... I now publically call upon the entire audio industry... to acknowledge polarity as a psycho-acoustic parameter and identify the polarity convention of their products."
That was 1979. But people are still in denial, still fighting the obvious. Sad, sad, sad.
clark
In his Audio article Dr. Heyser makes reference to Hansen & Madsen, On awal phase detection. These authors have used an artificial signal, just like Wood. Even with that signal they pointed out that "improving the transfer characteristics of the [test] loudspeaker resulted in weakening the subjective perception of the change in the applied signal."However, that paper addresses phase, not polarity. They did find that polarity inversion was audible, using a test signal and an additional control unit which allowed to reverse polarity, but they did not specify whether or not it was audible on all speakers (the poorer and the better ones) used for the tests.
Dr. Heyser mentions the tests he has performed himself, but he does not specify what speakers he has used and what test signals.
You see what I mean?
Klaus
can be done with a $300 receiver and the equivalent priced speakers.
I use a pair of Sonance Symphony 622C's. They are not time aligned, but sound pretty coherent and they are hooked up to a bottom of the line HK receiver.I believe speaker designs have deteriorated in that more (numerically) modern designs incorporate polarity inverted drivers. Older designs were much better aligned, at least in my experience.
I blame Harry Pearson of The Absolute Sound for this. He raved about the Proac Super Tablette which has the woofer inverted in polarity to the tweeter. 'Great Dimensionality and an unbelievably large soundstage' he gushed. That led all the manufacturers to adopt the woofer inverted design for smaller speakers. Monkey see, monkey do, or, in this case, Monkey hear, monkey do. Apparently HP can not hear polarity and phase issues.
Then some designer came up with inverting the midrange in a three way system, using the inverted frequency mid range to cancel out the overlap in the range of the adjacent drivers. A more even amplitude was claimed, which is fine if music was merely only sine waves (it ain't, folks!). Somehow it seemed to coincide with the rise of the PC and every one has been claiming 'computer designed' crossovers, as if just being available as a computer simulation makes it more correct.
It is true that an inverted midrange adds emphasis on the highs and the lows. Most novice listeners have difficulty in hearing the notes in the middle where most of music's fundamentals lie. A high frequency emphasis is heard as detail, and, of course, big bass is all about that visceral impact.
Ever notice that most speakers labeled as being analytical seem to suffer from an inverted driver? And then, I note the rise of the single driver speaker systems seem to coincide with the proliferation of the mixed polarity designs. There are many people who subconsciously, perhaps, know that something is wrong with many multi driver designs.
In a modern world where even singers use a synthesizer, and virtually no instrument is not electronically enhanced, few remember or even know what live unamplified instruments and singing sound like. But small changes in balance in the inverted designs can strike a certain chord in many listener's minds, leading to an endless chase for 'perfection'.
But you are most correct in that no one wants to point out speakers with phase, timing, or polarity errors. As you state, the simple tests results in Stereophile magazine point out many timing issues, but the magazine reviewers either choose not to point out problems or perhaps, sadly, they can not hear the problem. Or, perhaps the possible loss of ad revenue is more important than furthering the advance of audio.
Stu
It clears up a lot and answers a lot more.And if anyone needs further evidence that It's a dogma thing for our friend KlausR, read below.
For those who think that they hear absolute polarity, they should contemplate the following.Dan Shanefield, BAS speaker, vol. 17, no. 3 :
"once you see evidence of an additional factor which might really be causing the observed results, you should never ignore it in further studies. Instead, it must be carefully eliminated".
It has been shown (by Shanefield 1995 and Furindle 1976) that introducing distortion into the playback system makes polarity inversion more audible.
This reminds me of people claiming to hear the benefits of supertweeters. Then Kaoru and Shogo demonstrated in their AES aper that this is due to intermodulation distortion.So if it is possible that audibility inversion is audible because of good ole harmonic distortion, then that parameter should be investigated. But no.....
One answer to that problem is DSP. How many consumer speakers use DSP ?
Fortunately there are mags like Stereophile and Soundstage that provide meaurements. The ideal response curves are known from literature, such as JA's AES paper (available on Stereophile's website). One look at the graphs and you know the value of the speaker. But no....
Klaus
I have been subjected to 'tests' every time I go to CES. Unfamiliar material, unfamiliar equipment and have been asked to say correct or inverted after a minute or so of listening. I can hear polarity with a $300 receiver and speakers as well as in a high end preamp and amp combo in the $10K range with speakers in the matching price range. I'm sure their HD is quite low by anyone's measurement.You are searching for an easy out. The solutions are not quite so simple, but one would assume that you will have to start somewhere. I use real live listening sessions with real unamplified music as an absolute. You can measure away, buy expensive test instrumentation, but inevitably the final judge is the human ear (and I am NO golden ear!).
With all the technology which is currently available to us, I can not fathom why designers can not create a better speaker system which is phase and time correct and with adequate frequency response. The only answer I can see is lack of public interest (read $$$ here).
Stu
Maybe but without knowing a threshold you can't be sure. As far as I know such a threshold has never been determined nor have there been studies w.r.t how system distortion affects audibility of polarity inversion. Anyone serious about this issue would either conduct such studies himself or wait until such studies have beed conducted and solid data are available.A lot of advanced technology is available and only some use it. Speakers which are phase and time correct and which have adequate frequency response do exist, look at the ones I have. Given the fact that many audiophiles are willing to spend a lot money on speakers I frankly cannot understand why there's not more designers who implement technology that allows true improvement.
Klaus
Stu
Klaus, PLEASE read up on the state of human hearing in: 'Models of Hearing' by Manfred R Schroeder, in the 'Proceedings of the IEEE', Vol. 63, NO. 9, September 1975.
Heyser would agree, if he were here.
30 years ago: He said something like, "That should satisfy the little ........" or somesuch, but in a more polite way. Then, I said, "But Richard, who reads the' Proceedings of the IEEE' but you and me?" I was right, unfortunately.
I knew that Klaus would not bother to read up on the subject!
Please tell me where is polarity mentioned, where are the listening tests w.r.t aubility of polarity inversion using musical excerpts described. Tell me because I cant find any.
Klaus
"Although I agree with the major premise of the book - that absolute polarity is extremely important..."That of course is the crux of the matter.
"I must say that pages 67 to 74 are full of erroneous and misleading information about loudspeakers."
Not true; that section lambastes all loudspeaker designs in which phase is gemischt, disallowing the perception of polarity. Read it yourself.
The nonsense continues:
"The last two chapter are an odd mixture and, therefore, difficult to describe."
Perhaps for Mr. Long. Here's the description: Polarities on records etc. are found by experiment to fall 50/50 into both camps; proof is ascertained that this must be so .
"There is an interesting list of recordings, each marked with the author's own polarity convention, which is relative to the first record for which he determined the correct polarity."
No! Never, ever said that that polarity was "correct". In fact I pointedly avoided that.
"It would have been better if he had determined the absolute polarity of his own system before he began marking his collection."
Ah! Poor Ed... Over and over the point was made that systems do not possess their own "absolute polarity". Yet by way of excuse, people still do make that error.
At least Audio printed a huge color picture of the cover!
Did you catch John Cockroft's review in Speaker Builder? "I have become a disciple of Mr. Johnsen's dissertation." He grasped all the points that Ed Long missed.
Likewise David Shavin: "R.C. Johnsen has fired a barrage at the audio-recording industry. A combination of moral outrage, hard work, and intellectual acumen, mixed with wit, humor, and even street-theater antics, makes this 98-page book a rare and refreshing exposé, guaranteed to miss the audio industry's puff sheets."
On the other hand, John Atkinson reviewed it in Stereophile: Excellent, superb, a tour-de-force. But perhaps you'd rather concentrate on the negative?
clark
c
> On the other hand, John Atkinson reviewed it in Stereophile:
"Excellent, superb, a tour-de-force."
My September 1988 review is reprinted at www.stereophile.com/asweseeit/988awsi/index1.html .
Scroll down the page to the section on Absolute Phase.
John Atkinson
Editor, Stereophile
From the Stereophile review by JA:"Work by Stanley Lipshitz in the late '70s (footnote 9), using carefully organized double-blind testing, confirmed that a reversal of absolute signal polarity will be subtly audible on music to a 99% confidence limit! (Indeed, it is one of the few things that can be reliably detected with double-blind testing.)"
This statement is just... false. That's not what Lipshitz demonstrated - he showed that absolute phase was audible with 99% confidence, but using test tones (which everyone can hear the difference on) and musical selections (which evidently no one could hear the difference on). Combining data with 100% success with data with 50% success gives a very high confidence that there's an effect if you do enough trials, and that's what happened there.
And the bit about DBT at the end is rather silly.
s
You said that your book was lauded in Audio Magazine, when reading E.E.Long's review, I don't get that impression. That was the very point I was trying to make.Obviously also DDD Shanefield has got it wrong being "polarity deaf" ? Again, someone who did not laud.
Btw., did you write a letter to the Editor to clarify all those issues you are mentioning here and now?
Klaus
.
No, why should I, everybody is entitled to have an opinion about your book.However, JA is misleading the reader when paraphrasing from Lipshitz' AES`paper on phase distortion : "Work by Stanley Lipshitz in the late '70s, using carefully organized double-blind testing, confirmed that a reversal of absolute signal polarity will be subtly audible on music to a 99% confidence limit."
Whereas the Lipshitz paper states the following: "The authors have demonstrated the TWO-TONE experiment described above to numerous people on different systems. No one has ever failed to hear the timbral change with phase, and discern the polarity reversal on this signal with unvarying accuracy. Indeed, in a double-blind demonstration to 11 members of the SMWTMS audio group, the accuracy score was 100% on the summed 200-Hz and 400-Hz tones over loudspeakers, and overall, including musical excerpts, the results on the audibility of the polarity inversion of both loudspeaker channels were 84 correct responses out of 137, this representing confidence of more than 99% in the thesis that acoustic polarity is audible."
I suggest that the original text is radically different from what JA writes in his "as wee see it". Deliberately or not, JA is providing misleading information to the reader.What was the score of that part of the DBT where musical excerpts were used?
Klaus
So "subtly" it can't even be heard:
See link for the actual results of the study Atkinson was referring to. With music the score was 60 / 113 = 53%. That can reflect the result of mere guessing and provides of course no proof whatsover of any audibility; rather the opposite in all likelihood is the case.
That is, unless Atkinson is referring to another study by Stan Lipshitz that I'm unaware of. Barring that, why grossly misstate the results?
TL
...the audibility of Absolute Polarity on music. You choose to ignore his record here. Why?Of course we all know why!
It contradicts your erroneous case.
Also you continue to ignore Dr. Heyser. Why?
Because you have to!
Nor have you provided us yet with a scientific definition of "convincing" and "solid".
Looks rather hopeless, having a rational dialog with someone who dismisses the evidence.
clark
What were the scores of that part of the DBT where musical excerpts were used? THAT would be evidence that is interesting and relevant for consumers. THIS seems to be the only evidence obtained by Lipshitz, however, without a score, what do we know about the value of that evidence? I do not ignore his record, just tell us what the score was and we talk further!
Since we are speaking of presenting misleading information, tu quoque, filii:In your AES convention paper, page 13:
"The authors have demonstrated the TWO-TONE experiment described above to numerous people on different systems. No one has ever failed to hear the timbral change with phase, and discern the polarity reversal. Indeed, in a double-blind demonstration, the accuracy score was 100% [on a two-tone test] over loudspeakers, and overall, including musical excerpts, the results on the audibility of the polarity inversion of both loudspeaker channels represented confidence of more than 99% in the thesis that acoustic polarity is audible."
What you have omitted here is that, overall, only 84 out of 137 reponses were correct. How many response were correct when musical excerpts were played?
Further, in a letter to Audio Magazine 1994 that passage was further reduced to:
"In a double-blind demonstration....including musical excerpts, the results on the audibility of the polarity inversion of both loudspeaker channels represented confidence of more than 99% in the thesis that acoustic polarity is audible."You didn;t even mention that part of that confidence was based on TEST TONES.
What evidence? There's that Lipshitz SMWTMS audio group DBT of which the score is not known and that's about it.
I don't count all those experiments where artificial signals were used for obvious reasons. I don't count your own experiments for the reasons outlined before.
Klaus
Sufficient to say, their experiments satisfied them as to the efficacy of Absolute Polarity in bringing us all "Better Sound for Free", and they did not hesitate to trumpet this discovery to the world from every location they commanded.Pity the world won't listen.
clark
Do you have a Cassandra complex, Clark?
Clark, try and read carefully what I write.B.F.Muller, "Third World: The Scientific Subjectivist, Audio Amateur, vol. 11, p.64 (1980 Jan.).
Lipshizt, A little-understood factor in A/B testing, Boston Audio Society speaker, vol. 6, (1978 March)
Lab books indeed!
Klaus
> You said that your book was lauded in Audio Magazine, when reading E.E.Long's review, I don't get that impression. That was the very point I was trying to make.Hey, they gave it two pages and a color photograph.
> Obviously also DDD Shanefield has got it wrong being "polarity deaf"? Again, someone who did not laud.
Dan Shanefield is one of only two people on record (so far as I know), besides yourself, who dismiss absolute polarity. Besides which, Dan has been outright rude to my face -- not a pleasant person.
I notice that you have nothing to say about Atkinson, Cockroft, Heyser et al. Perhaps just as well, for you.
> Btw., did you write a letter to the Editor to clarify all those issues you are mentioning here and now?
No. I was advised that Ed Long was their golden boy at that time and they wouldn't print it. Besides, the review sold a few hundred copies, and who am I to disagree with success?
Klaus
You did not adress the components-in-the-crossover issue. What about those?Your "evidence" is not convincing because of the flawed experiments. Read the old thread and you'll find all the arguments.
Klaus
...yourself. And a rather haughty self, at that.We still await a scientific, or better a numeric, basis for your assertion. You're the so-called "scientist"! Come on, act like one.
The evidence is overwhelming: The polarity call for any track on any medium remains consistent through any arrangement of gear, capacitors, wire etc. Were those the operative agents, no such consistency would prevail.
You're snatching at defeat, again. Give it up.
clark
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