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Critic's Corner

some thoughts on polarity

69.200.83.8

There's been a discussion in several threads here on the issue of the audibility of polarity reversal (let's define that to mean the effect of reversing the speaker cables on each speaker, or anything else equivalent) during music playback. I've done a few little experiments with it, and I thought some inmates might be interested in the results and discussion.

I want to preface this by saying that anecdotal evidence one way or the other isn't going to add very much to this discussion. Double blind results and a theory that accounts for them are the only thing that's going to advance this issue. I think that's clear from the recent history - 50 years of anecdotal evidence hasn't gotten anyone to take this seriously.

The first question to address is whether polarity reversal is EVER audible. Many people believe it is not, but they are mistaken. Let's see how we can make it as easy to hear as possible. First of all, it's obvious that only for an asymmetric signal (meaning one which is significantly different when inverted) can we expect to hear something. On a steady pure tone, for example, polarity can not possibly be audible because the inverted signal is identical to the original, time shifted by one-half period. So let's construct a very asymmetric signal and listen for the effect there.

To do this, take any audio program (Audacity is a good free example) and generate a pure tone at, say, 400Hz. Now generate another at 800Hz, but shift the phase by 90 degrees relative to the first. Summing those two signals gives a very asymmetric waveform. If you want to make it even more asymmetric, add another signal at 1200Hz with phase 180 degrees shifted from the first (etc.). If you look at that signal, the negative parts are of higher frequency but lower amplitude than the positive parts. The DC offset is zero. Note that it's crucial that these components be harmonic - anharmonic combinations (meaning combinations of pure tones where the frequencies are not integer multiples of some base frequency) are phase incherent (the polarity reversed signal looks the same, at least when averaged over a few cycles), and so polarity reversal can not be audible for them.

Now take that summed signal, call it test1, and make a new signal which is inverted (the invert function in Audacity does that for you). Call that test2. Now download a player with an ABX comparator (foobar2000 with the ABX plugin for example) and see if you can hear a difference.

After a little practice I found that quite easy. It sounds like one tone has a higher frequency than the other. Now let's say on a particular trial A sounds higher pitched than B. Here's where it gets really interesting - my headphones (Grado's) can be rotated so that the speakers are facing outwards, away from the ears, rather than inwards. When I wear them like that, I can still hear the difference (10/10 correct on ABX), but now B sounds higher than A!

This result has several implications. First of all, it proves that the difference I'm hearing is in my ears, not to anything in the playback chain like the computer or the phones. If the difference was due to distortion in the phones, for example, inverting them wouldn't change anything.

Second, it supports the hypothesis that the reason polarity is audible is that the ear acts roughly as a half-wave rectifier - that is it chops off the part of the signal that is a rarefaction, say, but not the part that's a compression (it might be the opposite, I don't know - one could actually find out by determining which way the phones are moving and checking which way sounds higher pitched). The pitch change is evidently due to the fact that this signal, when rectified one way (keeping the positive part), will have higher frequency than when rectified the other way (keeping the negative part).

So polarity reversal is audible on certain asymmetric test tones, and the likely explanation is that the ear/brain acts to a first approximation as a half-wave rectifier.

Now the question of interest to this forum (and presumably audiophiles in general) is whether polarity is audible for recorded music. I think the answer is almost always no on a system with low distortion, but I'll come to that in the next post.

Follow Ups:

re:Polarity...a PLOT of "said" waveform - PeAK 06:28:40 07/11/07 (0)
For those who have a tough time visualizing Truthseekerprime's assymetric waveform, take a look at the yellow curve in the plot above. In the first part of the cycle, we see the 400 Hz (low frequency component) and in the second part of the cycle, we see the higher frequency 800 Hz component. Pretty neat!#$!...adds another chapter to this puzzle...
PeAK

Edits: 07/11/07
Afraid I agree with Dave Pogue, DG is easy to pick, for me - Timbo in Oz 17:10:48 06/14/07 (9)
OTOH it is IME easier to demonstrate polarity to skeptics - if;

you have recordings that are in real / simple stereo or that approach this, even spced Omnis with 2 mikes Mercury's or 3 eg. Telarcs.

A room/sytem where early reflections are in some way minimised for the listening area.

And the system is set up to maximise information from such recordings, and not add to it.

the speakers are 'coherent' / launch sound waves well.

Good diffraction behaviour by the spkrs certainly doesn't hurt. IMO &E. most boxes really are crap at this!

It also helps if the system's (room?) rise and decay speeds - at the listening area - approach a good match. Very few systems that I know well have this, mine does! ;-)! Treatment helps

Why?

Expression, getting it by us that is, along with individual timbre, are very much embedded in the attacks and decays of individual notes. (And attacks are compression rich!) As are our ability to hear the space around the music and the positions of sources in it.

I think that the difference between a compression and a rarefaction may well have been of evolutionary value to most animals. .......

Hence I like to suggest that along with using the alternative term for 'instrument note attacks' - starting transients - which IS a richer term, I also like to call them 'startling' transients! ;-)!

Warmest
Timbo in Oz
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
http://www.theanalogdept.com/systems_gallery.htm
- IOWords a LOT of waht MATTERs to humans in getting music is about asymmetrical wave forms - Timbo in Oz 17:19:18 06/14/07 (8)
  and continuous tones including that middle bit of a note - where an instrument CAN do them on any note*, don't have anything like as much importance.
  
  so, when you can get past 'test-tones that last', you might get it!
  
  *Piano notes just don't have have a continuous tone - so how can we TELL it is one, eh?
  
  Or which model / brand?
  
  THINK about it.
  
  gwarn, be brave, step out and truck on down to where music's AT, maaate!
  
  Warmest
  Timbo in Oz
  The Skyptical Mensurer and Audio Scrounger
  And gladly would he learn and gladly teach - Chaucer. ;-)!
  'Still not saluting.'
  http://www.theanalogdept.com/systems_gallery.htm
  - "Piano notes just don't have have a continuous tone - so how can we TELL it is one, eh? " - truthseekerprime 18:00:01 06/14/07 (7)
    We can tell it's a piano by the harmonic balance of the tone - not by the polarity. That much is obvious from the fact that polarity reversed piano recordings still sound almost, or perhaps exactly, like polarity unreversed piano recordings ;-).
    
    Still, when I have a chance (which may not be until almost a month from now when I return from a trip) I'm going to record some trumpet tones played with a tongued attack and see if I can hear the effect of polarity inversion.
    - Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono - Timbo in Oz 18:05:34 06/14/07 (6)
      maybe YOU can't hear AP!
      
      Harpsichords are good too.
      
      IME OOP pianos don't sound QUITE as definitely pianos as IP ones do, okay!?
      
      And, they certainly don't sound clear by comparison.
      Warmest
      Timbo in Oz
      The Skyptical Mensurer and Audio Scrounger
      And gladly would he learn and gladly teach - Chaucer. ;-)!
      'Still not saluting.'
      http://www.theanalogdept.com/systems_gallery.htm
      - RE: Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono - truthseekerprime 07:03:16 06/15/07 (5)
        
        In Reply to: RE: Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono posted by Timbo in Oz on June 14, 2007 at 18:05:34
        
        OK - why not try a blind test, then? Do you have a PC based audio system? If so you can easily do a blind test and make a very useful contribution to this discussion. If not you can still do it with a helper. The most interesting thing to know is whether polarity (on piano, for example) is audible at all in a controlled test; if so, is it the attack of the note or the sustained part, or both? You could test that for example by making a recording with just the sustained part. It's also useful to know what kind of audio system you're using - if you're using LPs the results are somewhat less interesting due to the harmonic distortion that introduces.
        
        RE: Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono - unclestu52 22:15:36 06/15/07 (1)
        
        In Reply to: RE: Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono posted by truthseekerprime on June 15, 2007 at 07:03:16
        
        Don't forget that the piano is actually a percussive instrument which has hammers hitting the cluster of three strings. The initial wavefronts are very assymetrical. Also because the three strings are not tunes precisely identical, the harmonic structure and the interaction of the three is slightly different if the notes are sustained.
        
        As previously stated try the Holly Cole Trio's 'Don't Smoke in Bed' CD. It made TAS's recommended list of recordings. It's a simple (well relatively) recording of a voice, bass and piano. The voice and bass are inverted in polarity in respect to the piano.
        
        I can hear this inversion quite readily and I do not claim to be a 'Golden ear'. This common CD should lay rest the concept if polarity is audible with music, at least if your speakers are relatively phase and time aligned (sorry, for me polarity is just a subset of the larger phase issue and simply restricted to the case where it is 180 degrees out).
        
        Stu
        
        RE: Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono - truthseekerprime 11:14:55 06/16/07 (0)
        
        In Reply to: RE: Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono posted by unclestu52 on June 15, 2007 at 22:15:36
        
        Well I now have a CD which someone earlier recommended as having easily audible polarity inversion. Unfortunately I'm going to be traveling for the next three weeks, but I'll experiment with it when I get back.
        
        there's NO sustained part in a piano note, did you not get that! - Timbo in Oz 12:36:10 06/15/07 (2)
        
        In Reply to: RE: Some people can't hear stereo ever I've met 3,a nd they could only hear AP on phones on mono posted by truthseekerprime on June 15, 2007 at 07:03:16
        
        There's NO sustained part in the notes of lots of instruments! harpsichord, clavichords, cymbals, drums, .....
        
        And, I don't need to do a blind test, I know I can hear it, and that it makes a difference.
        
        Warmest
        Timbo in Oz
        The Skyptical Mensurer and Audio Scrounger
        And gladly would he learn and gladly teach - Chaucer. ;-)!
        'Still not saluting.'
        http://www.theanalogdept.com/systems_gallery.htm
        
        You're the one with the problem in accepting AP - do bear that in mind - Timbo in Oz 13:01:03 06/15/07 (1)
        
        In Reply to: RE: there's NO sustained part in a piano note, did you not get that! posted by Timbo in Oz on June 15, 2007 at 12:36:10
        
        And I don't have a problem with science, and I could probably write a book on hypothesis testing.
        
        I've ahd an AP switch in mys system since the early 90's and was swapping spkr leads until then, and got sick of it. So, ..... how many tests is that? eh?
        
        Statistics was part of my career, and I am a sceptic about its use, to the extent that I questioned the use and reports of several groups in Government, and was proved right, ever done that in your career?
        
        We already have blind test results that show AP is audible.
        
        IME it is most audible on live broadcasts of acoustic concerts on FM, usually simply miked, often in real stereo. Or on tapes made in simple stereo. Noting that a direct broadcast like that is only slightly more processed that such a tape.
        
        Warmest
        Timbo in Oz
        The Skyptical Mensurer and Audio Scrounger
        And gladly would he learn and gladly teach - Chaucer. ;-)!
        'Still not saluting.'
        http://www.theanalogdept.com/systems_gallery.htm
        
        "We already have blind test results that show AP is audible. " - truthseekerprime 11:13:44 06/16/07 (0)
        
        In Reply to: RE: You're the one with the problem in accepting AP - do bear that in mind posted by Timbo in Oz on June 15, 2007 at 13:01:03
        
        Reference, please? Unless it's to test tones - I've done that myself and there are plenty of references.
        
        Look, it's not that I'm doubting your credibility, it's just that to advance this subject anecdotal reports are next to useless. The reason is that we simply have no idea what it is that makes AP audible - is it distortion in the audio system, is it attacks of notes, is it sustained tones, is it some combination, is it only audible with certain types of speakers, etc. etc. etc. There is simply no way to nail all that down without careful, controlled tests which isolate the possible causes.
RE: some thoughts on polarity - truthseekerprime 17:38:03 06/09/07 (2)
Thinking about how to make recordings that preserve at least some of the original polarity of the sounds, I realized the situation isn't quite as bad as I had thought.
Let's use the term "ambient mics" to refer to microphones which record at once more or less all the intruments/vocals being produced (is there a better term for that?), as opposed to "monitor mics", which record only the sound of a single instrument. That might be either because they are situated very close to one instrument, because the engineer simply records the electrical signal of an amplified instrument rather than using a mic, or because the recording was made in a studio where each instrument was acoustically isolated and recorded separately.
A problem arises when the tracks from two or more ambient mics which were more than a short distance apart are mixed. In that case there will be a set of time-delays from each instrument to each mic, proportional to the distances between that mic and the instrument. Since in general all those time-delays are different, there is no way to time-align the tracks so as to preserve the proper attack transient from all the sound sources at once. It would be possible to time-align on ONE source, but only one. Furthermore even one source is problematic when the polarity of the sound depends on the angle from the listener to the instrument. For example a plucked string produces a different leading edge when plucked towards a mic than when plucked away, so mixing mics situated on opposite sides of the string will produce a sound which may not correspond to any real sound that string could produce.
Clearly all these difficulties can be avoided by using only two mics - one per channel. However that has many disadvantages - for example it means the recording will be very sensitive to the placement of the mic if there are any room modes in the recording space, and it prevents engineers from being able to adjust the harmonic balance and relative loudness of instruments as they would like.
It seems that many of these difficulties can be overcome by using only one ambient mic per channel plus any number of monitor mics. Each monitor mic, because it records only one instrument, can be separately time-adjusted so that it is in time with the ambient mic. There still might be a problem with angle-dependent polarity, but it could be minimized with proper placement of the monitor mics (you'd want them located along the line between the instrument and the ambient mic). Combining monitor mics with one ambient mic should allow a large degree of control over the balance etc.
Of course it still remains to be demonstrated that it's worth going to all this trouble...

Edits: 06/09/07
- RE: some thoughts on polarity - unclestu52 23:04:11 06/15/07 (0)
  You are heading towards the correct analysis and are asking some very precise questions.
  
  When I became aware of polarity issues, I scoured the racks purchasing LP's (I'm an old fart) with recording information on them. You can learn a lot from them. Merc's, as previously pointed out, use simple three mike recordings. The first three stereo RCA's, LSC 1806, 1817, and 1893 use a two mike set up. Later recordings employ up to 6 or 7 mikes for spotlighting.
  The early Decca use the famous Decca tree. Kavi Alexander who has the Waterlily label uses a single stereo mike, and he has done extensive work for Audio Quest as well as Vandersteen label. A careful scrutiny of these recordings and an analysis will reveal anomalies and differences with the various set ups ( and other issues also such as the gain riding on the Decca's).
  
  If you haven't also tried it, please try listening to Ray Kimber's microphone technique: even the four channel demos are quite remarkable. He also is attempting to correct for the playback situation where usually the speakers are roughly 10 to 12 feet apart.
  
  One of the central issues is that most playback systems are normalized for the listener's favorite music and concept of sound. Take Harry Pearson of The Absolute Sound. He is on record as stating he admires the sound of Carnegie Hall and frequently attends concerts there. However, if a recording of the Chicago Symphony recorded at Symphony Hall is played back on his system it should not sound like Carnegie. A truly neutral system sounds, well, like the recording, no more nor less.
  
  I still remember when I first set up a fairly neutral system. I was stunned at the information presented. Dave Wilson's 'Winds of War and Peace' always sounded a bit strange to me. After getting a neutral set up, I could tell that the players were facing each other and set up in the traditional 'U' shaped arrangement (confirmed much later by an observer at the session). On the famed Eastman Wind Ensemble recordings, I could tell that the players were also not arranged in the orchestral 'U' shaped formation but sitting in staggered rows. A picture of their formation can be seen in the Civil War sets put out by Mercury.
  
  Curiously with modern multimiked pop recordings, particularly the 'jazz' ones, there is a better chance of getting the various mikes in correct phase, since every instrument is individually miked. The problem becomes that producers use polarity inversion to accentuate certain instruments or voices. Casual listeners will not pick much of this up and merely right off the inverted parts as due to inadequate performers. The sound should be much more up front since the mikes are typically clipped onto the instruments themselves.
  
  As for an classic example of the problem of mixing mikes at various distances from an ensemble, the latest recordings of the Philadelphia by Ondine are quite revealing. When I visited Verizon Hall I noted something like 17 mikes suspended from the ceiling with a lot of spotlight mikes over the orchestra center section (the woodwinds and brasses). Mixing all of these in real time and since the mikes for the string sections (being a much larger ensemble) are placed further away leads to a jumbled 'phasey' recording.
  
  I have an acquaintance who plays in the Philadelphia, and is naturally quite proud of the organization. He was devastated when I told him that the quality of the ensemble as judged from their recordings was only so-so. Indeed, when I finally got a chance to hear them live, I was stunned by their precision and ability to play together. You can not hear that quality in their recordings, unfortunately.
  
  Stu
- If this is the case, - Dave Pogue 05:11:45 06/12/07 (0)
  why does the label which is often the poster child for multi-miking -- DG -- exhibit the most obvious (to me at least) and consistent polarity? With very few exceptions in my collection, DG LPs, R-R-tapes, and CDs were recorded in "inverted" polarity. They are always my demo rcordings when illustrating the phenomenon to a "polarity newbie." Your argument seems to make much sense, but ...
  
  On the other hand, Mercury Living Presence recordings, famed for their minimum-miking ALSO exhibit this (inverted) polarity quite consistently.
Some interesting tests, but this is all irrelevant. Give me the ability to switch and I will decide myself. - Norm 06:43:34 06/06/07 (49)
Given the opportunity to switch I have heard differences that I would like to always have available. If people hear differences and want the capability to have the choice, would you deny them the choice?
- Give it up, Norm; he reverts to photo-in-the-freezer, the default position on his audio-mind's Commodore. - clarkjohnsen 11:42:31 06/06/07 (46)
  Ridicule keeps his circuits from shutting down whenever he espies other people talking about things he can't hear or understand.
  
  clark
  - I would have expected you to be a staunch supporter.. - rick_m 14:15:34 06/06/07 (45)
    of anything that helps to understand and further the cause of absolute polarity.
    
    Clark, you have turned yourself inside out to promote this cause, and I think you've done some real good. However the next step is surely to promulgate a body of knowledge and opinion sufficient to get both the folks that record and engineer the music and the consumers who listen to it to insist on a system-wide solution.
    
    IMHO the best hope for that is to try and nail down what's going on enough to do some effective arm twisting at both ends. Surely this is at least an attempt to move in that direction...
    
    Rick
    - Thank you! "The next step is surely to promulgate a body of knowledge." - clarkjohnsen 09:44:11 06/07/07 (2)
      That's a damn good idea! However, I had it already back in 1982; after five years of research I came out with a book (or a really long monograph) entitled The Wood Effect, which gathered all known information on the subject through 1987. The proofs of an audible Absolute Polarity were incontrovertible (one would have thought).
      
      It was received with gratifying acclaim.
      
      But did that do anything to change minds set on the contrary?
      
      Or bring the topic into closer focus among writers and audiophiles?
      
      Or cause some standards to be set (granted, a tricky proposition)?
      
      Would you care to guess?
      
      With 4,000 copies in print and numerous favorable magazine reviews one hoped for more immediate results.
      
      However, there are some, perhaps many, who have finally seen the light. Recently a copy went for a whopping $98 on eBay (or was it Amazon?) and I quickly got a call and an embarrassingly complimentary letter from the proud new owner, who was actually a recording engineer. He said the book confirmed everything he had suspected, and that his studio would henceforth undertake to be sure to regularize the polarity of all their output.
      
      I should have sent him flowers. Maybe I still will!
      
      So the message seeps out, albeit slowly. Some day I'm sure polarity will be recognized as the primo inter pares audio phenomenon I've always said it was. Until then, we who find it a highly audible factor are doomed not only to be dismissed most ungraciously by the forces of darkness, but also to fend for ourselves when it comes to correcting for our mixed-up tapes, LPs and CDs -- never mind the Net and the radio!
      
      As for setting "standards", rotsa ruck in this iPod-diminished world. Even back in the Nineties I made some effort with an ad hoc AES Committee on Polarity to convince them this was an acoustic-based phenomenon, hence any approach to a standard had to be based on that factor. Although an AES member of good (and long) standing, I was rather huffily instructed that what I proposed was irrelevant. I replied to the contrary etc. etc. Recently I reviewed our fruitless correspondence and came to the same conclusion as back then: Absolute Polarity was an impossible concept for the AES. Thus I dropped my effort. Finally, the weak and even more confusing "standard" they wrote was never adopted, a wise decision indeed.
      
      Nor have I ever updated or reissued The Wood Effect; although much new evidence is available (and I did once write a new, possibly more helpful intro), I cannot see my way clear to assuming that such an expensive effort would at last turn the tide. But, again, I do sincerely thank you for your interest in the Cause.
      
      clark
      
      PS Almost missed this: You moot a "system-wide solution". I have it! Anyone care to fund the project?
      - Twenty years may be enough... - rick_m 13:13:40 06/07/07 (1)
        
        In Reply to: RE: Thank you! "The next step is surely to promulgate a body of knowledge." posted by clarkjohnsen on June 07, 2007 at 09:44:11
        
        to soften the resistance! If you are still interested...
        
        Besides the medical allegories, there are numerous examples in science and engineering. I think the bottom line is that human thought, such as it is, has a lot of momentum and that pride easily perverts reason. Rarely does the creator or publicist of a new idea profit from it socially or monetarily. Actually they are usually scorned as crackpots and heretics and banished to the fringes of polite society if not prison. Ending up broke and bitter is common.
        
        Eventually however, the seditious thoughts they launched have echoed about sufficiently that the clever marketing maven or businessman can act upon them often reaping enormous profit and praise by commercializing the work done earlier by another. That's my historical take on it. 'Taint fair, but that's usually the way it goes.
        
        On the other hand you're not broke or dead yet and your name is well linked to this concern. It isn't REQUIRED that the originator die and then spin in his grave when everyone else comes around, it's merely typical.
        
        Beyond the passage of time and dispersion of your notions, two factors that suggest that the time may be ripe for this to take hold are iPods and aging baby-boomers.
        
        I'm at the leading edge of the latter and I'm here to tell you that when I was growing up and young that everyone I knew really cared about stereos and sound quality. Now that we are shed of the kids and almost shed of the jobs we'll have time for the important things, such as our stereos.
        
        At the other end I think your view of iPods is inverted. More youngsters with good hearing are now listening to stereophonic music on equipment good enough to reveal intrinsic technical quality than ever before in history.
        
        So... you may feel too bitter and burned-out to lead the charge further, but if you encourage and prod others to action, you may yet see your hope realized. Meanwhile, thanks for helping us enjoy better sound.
        
        Regards, Rick
        
        Thanks for the inspirational message -- in marked contrast to my various antagonists. - clarkjohnsen 09:40:07 06/08/07 (0)
        
        In Reply to: RE: Twenty years may be enough... posted by rick_m on June 07, 2007 at 13:13:40
        
        And yes, of course I'm still interested!
        
        Regarding "science" we seem to be in agreement: Take a gander at the URL below.
        
        And of course, "the pioneer takes the arrow".
        
        The proposition that, ah, young people today are again interested in stereos, I do find doubtful however. I can name only one: Josh Ray of sonicflare.com
        
        Am I bitter? Yes! But not about the non-recognition of polarity. As Mahler once said, "My time yet will come." And so it did.
        
        What *bothers* me though, is an audiodom that goes slavering after all sorts of expensive gew-gaws while virtually ignoring what they can do for themselves at home; in this connection they are supported by all the magazines (except Positive Feedback), which teach them only the craft of connecting new components together.
        
        And here they are offered Better Sound for Free -- and they don't believe it! Because they don't have to -- buy it!
        
        As you know I'm also at the forefront of tweak applications, which are indeed sold, although mostly they are not costly -- which means, again, they lack cachet.
        
        As for those poor fellows yammering at me about double-blind tests, my "refusal to accept definitions" (heck, I made the definitions!), my despair at enacting "conventions" (as though any such would do something to rectify the millions, billions maybe of hours of music already recorded), and my exasperation at their rude behavior (which I rarely bother to answer) -- well, they just can go home and ignore reality can't they?
        
        Yet withall, the answer to all the above is so simple! I remain astonished that no one seems to have arrived there.
        
        Again, thanks for the nice words. Hey! Want in on the ground floor of a great new business? I have no plan...
        
        clark
        http://www.audioasylum.com/audio/general/messages/48/482817.html (Open in New Window)
    - RE: I would have expected you to be a staunch supporter.. - unclestu52 19:42:31 06/06/07 (41)
      If you appoint yourself the 'guru' of polarity, you can not tolerate any one else who may explain phenomena better than you can. CJ can not sell his books if he is knocked off his pedestal. It is a very simple matter of economics, it seems. Keep the public confused and you can sell more books.
      
      As for promulgating change and a step forward, that is also against the economic interests of CJ. After all, his book does not even attempt to create a solution.
      
      I have been very disillusioned by his stance. He attacks every attempt to ameliorate the problem. He denies all definitions, but does not establish any of his own. He will criticize any one who disagrees, but he will also attack others who support his very position (that polarity is audible). His is a very perplexing position, and a frustrating one since many critics seem to back him up (of course maybe they'd just rather not argue with him, a position I can understand seeing his responses on AA). He hovers on the edge, recognizing that there is an issue, but cannot solve the problem or even propose an attempt at a solution.
      
      Very frustrating.
      
      Stu
      - RE: I would have expected you to be a staunch supporter.. - TomLarson 20:07:15 06/06/07 (40)
        
        In Reply to: RE: I would have expected you to be a staunch supporter.. posted by unclestu52 on June 06, 2007 at 19:42:31
        
        I don't think he's primarily concerned with selling books. In fact I asked him to sell me one some time ago and then never heard back with a definitive "send me the money". My bet is that he's much like Gordon Holt in this regard--much better at audio writing than audio profiting (if that's a word).
        
        RE: "don't think he's primarily concerned with selling books" - tlyyra 03:47:45 06/09/07 (1)
        
        In Reply to: RE: I would have expected you to be a staunch supporter.. posted by TomLarson on June 06, 2007 at 20:07:15
        
        Correct, there are also all these intelligent chips, colorful marbles (all lost by now?), CD grinding (or was it sanding?) techniques, and green ink pens with the help of which we can lift the sonic performance of those sound carriers almost to the elevated levels of 78 rpm vinyl, as evident to any "trained listener."
        All on offer by this "tweako guru extraordinaire" (as promoted by his friend Bill Gaw at PFO), even if appearing like a salesman might be unbecoming a prophet of true and great calling. But no doubt the time of such epoch-making, paradigm-shifting breakthroughs yet will come, too, as did that of Mahler! (Sorry, clarkjohnsen, I find that analogy you draw between the success of your personal business projects and the trajectory of this great composer not just a bit ridiculous but indeed quite offensive.)
        TL
        Two Great Prophets of the 20th Century. Now only, one of them needs to return the world to a premodern stage to get recognition, not help it advance f (Open in New Window)
        
        Edits: 06/09/07
        
        RE: "don't think he's primarily concerned with selling books" - TomLarson 15:13:45 06/09/07 (0)
        
        In Reply to: RE: "don't think he's primarily concerned with selling books" posted by tlyyra on June 09, 2007 at 03:47:45
        
        Well, I think a bunch of those things you mention refer to reviews of products. Not the same as a monograph for one. And if you are anti-tweak you're in the wrong hobby. Because for 500 bucks (including Insigna speakers) you can buy a nice receiver-based two channel system at Best Buy that 90% (or more) of American listeners would say sounded just fine--playing cd's not lps, no tweaks, lamp cord speaker wire, interconnects suppied with the dvd player etc. You can rail agains cd stoplight or whatever it is, but at what point do you stop? I'll bet it's way after the average music lover stops. And so what's the point? You don't think his reviews of those products were accurrate? What reviewers do you trust? And on what basis.
        
        Thanks! And you are correct, I am poor at "profiting". On the other hand... - clarkjohnsen 09:56:10 06/07/07 (37)
        
        In Reply to: RE: I would have expected you to be a staunch supporter.. posted by TomLarson on June 06, 2007 at 20:07:15
        
        ...I seem to be mighty good at attracting churlish antagonists! One of the worst even claims I want to "keep the public confused [so I] can sell more books." Right! A book that attempts to allay confusion. And further: "He denies all definitions, but does not establish any of his own." That one is especially risible, as I have also been criticised here (by the way-more-polite Ted Smith) for a far too rigid set of definitions of phase and polarity. Just goes to show, you can't please everyone -- but I can survive just fine if I displease only the rude ones.
        
        As for getting you a copy, I must confess: I organized, then misplaced a whole list of names and addresses. If you would (privately) resupply same, I'll be sure to act promptly.
        
        Also see my longer note somewhere near above.
        
        clark
        
        Before I criticized you - unclestu52 02:45:02 06/08/07 (36)
        
        In Reply to: RE: Thanks! And you are correct, I am poor at "profiting". On the other hand... posted by clarkjohnsen on June 07, 2007 at 09:56:10
        
        you would always say the answer was in your book and the definitions plainly presented. Twenty years later, there is still much confusion, and no movement forward towards any solution. As a matter of fact, at first you said there were NO conventions for the establishment of polarity. Even after others pointed out references available in the 'net' which clearly define polarity, you refuse to accept those definitions. Yet, you still have to postulate a definition of your own, at least to your satisfaction (I've only seen you shoot down any attempt by others to do so). You can continue to wave the flag, but in terms of a solution or establishing a a movement towards resolution, I would point out that twenty years (after publication) obviously has not helped the issue any.
        
        It is very disappointing to witness. If I am rude in pointing out certain evident facts, so be it. But please remember, you were the first to call me names and no amount of asterisks can conceal what you meant, not when you provided the first and final letters. Your attempt to turn the facts against me is childish, but I guess if you repeat it often enough, some may believe you.
        
        So now, how long before you propose a solution for the definition of polarity and a solution for it's manifestations? Or is it as you have stated before, saying that it is all a mess anyway so why bother? And if we shouldn't bother, why should we even read your book which has no solution or a real definition (the AES proposal at least defines the movement of a microphone diaphragm and the vector of the electrical pulse to start!). Two decades and there has been little progress in enlightenment for the average listener.
        
        Stu
        
        Just wondering, have you read the book? nt - TomLarson 19:16:19 06/08/07 (35)
        
        In Reply to: RE: Before I criticized you posted by unclestu52 on June 08, 2007 at 02:45:02
        
        Yes ( nt ) - unclestu52 01:15:26 06/10/07 (1)
        
        In Reply to: RE: Just wondering, have you read the book? nt posted by TomLarson on June 08, 2007 at 19:16:19
        
        Stu
        
        RE: Yes - unclestu52 01:46:00 06/10/07 (0)
        
        In Reply to: RE: Yes ( nt ) posted by unclestu52 on June 10, 2007 at 01:15:26
        
        I had stumbled on polarity issues independently of reading Clark's book. I came to his attention after writing a short article for my customers, and one of them apparently sent the article to Martin DeWulf, who asked me if he could publish the article in his Bound for Sound Newsletter. I gave approval and from there the article was passed on ultimately to Clark.
        
        In all generosity, he actually sent me a copy of the book for free.
        
        Stu
        
        Should we read the book? - tlyyra 04:38:19 06/09/07 (32)
        
        In Reply to: RE: Just wondering, have you read the book? nt posted by TomLarson on June 08, 2007 at 19:16:19
        
        From "Bibliography" in Greiner and Melton 1994:
        "R.C. Johnsen, The Wood Effect (privately published monograph, 1989, 98 pp.). This monograph use quotes and paraphrases of anecdotal accounts of the audibility of polarity. It also gives the strong and personal observations of the author on this and other issues about audio reproduction which are highly controversial. There is no bibliography."
        Now, anyone with a serious interest in the subject matter would most certainly pass by an account of this kind when searching for references. This is a description of a pamphlet and not of anything that might be helpful for research purposes, and the description is by two of the researchers with the most distinguished record in exactly this field.
        Put that against the author's truly messianic claims that this pamphlet "explains everything" about the topic and that the "proofs" it offers (just how it can do that, based on paraphrases of anecdotes, is not clear to me) are "incontrovertible," and you are in a position to make up your mind about sending that check to Clark Johnson's home address or perhaps not minding being labeled by the author as belonging to "the forces of darkness" if you decide not to do that.
        On the other hand, it's nice to have some entertainment during the private moments at home, but that's another kind of choice.
        TL
        
        Edits: 06/09/07
        
        RE: Should we read the book? - TomLarson 09:05:52 06/09/07 (31)
        
        In Reply to: RE: Should we read the book? posted by tlyyra on June 09, 2007 at 04:38:19
        
        My ONLY point was, where I come from, bitching and complaining and deriding a written document that you have not read is absurd and of no value, intellectual or otherwise. I don't know if you SHOULD read it...hell, that's your choice. But if you HAVEN'T read it, you have no grounds (except irrational ones) to criticise it. If word of mouth tells you it's crap, don't read it. If an author's comments (besides what's in the book) sound like crap to you, don't read it. I guess you are quoting from some published opinion of the book. Great. It's called a secondary source and as long as all you're doing is ranting on a web site, that's great. (I wouldn't recommend research for you) That's all.
        
        RE: Should we read the book? - truthseekerprime 09:47:46 06/09/07 (30)
        
        In Reply to: RE: Should we read the book? posted by TomLarson on June 09, 2007 at 09:05:52
        
        It is telling that serious and professional researchers on the subject dismiss that book out of hand as a bunch of anecdotes and personal opinions unsupported by any evidence. And it's not surprising, given the statements of its author on this board - which speak very clearly for themselves.
        
        It's evident that if the issue of polarity in music is to be taken seriously, a serious attempt to study it will have to be undertaken. The first task is to determine if, when, and why polarity is audible in music. Only once that has been established will it be possible to move forward.
        
        Formulating a standard for preservation of polarity during recording and mixing is only possible if we can understand which aspects of it are audible and need to be taken into consideration. For example, does this putative audibility arise from transient "attack" tones at the beginning of notes, or from steady tones, or both? Knowing that is utterly essential, because (for many reasons) it is highly advantageous to mix down multiple tracks into one channel. It MIGHT be possible to do some mixing and preserve the characteristics essential to polarity, but only if those characteristics are understood first.
        
        Compromises must always be made in the artificial reproduction of sound. One doesn't want to sacrifice realistic or desired harmonic balance (which is CLEARLY audible) for absolute and rigid adherence to preservation of phase/polarity. Instead one should find a compromise, but that's not possible until the factors are understood.
        
        RE: Should we read the book? - TomLarson 11:04:58 06/09/07 (29)
        
        In Reply to: RE: Should we read the book? posted by truthseekerprime on June 09, 2007 at 09:47:46
        
        It IS surprising to me that as far as I can tell, a good number of the most vocal critics of the book have not read it. That is what seems absurd, all of the pseudo-intellectualizing aside.
        
        Oh they huff and they puff... and they blow themselves silly. You're right: Typical web ranters. nt - clarkjohnsen 12:54:40 06/10/07 (0)
        
        In Reply to: RE: Should we read the book? posted by TomLarson on June 09, 2007 at 11:04:58
        
        xd
        
        "a good number of the most vocal critics of the book have not read it." - truthseekerprime 11:22:31 06/09/07 (27)
        
        In Reply to: RE: Should we read the book? posted by TomLarson on June 09, 2007 at 11:04:58
        
        I haven't criticized (or read) the book, so I guess you're not referring to me. Greiner and Melton did read it, however...
        
        Quoting someone who doesn't like it is pretty lame in my opinion. nt - TomLarson 15:08:08 06/09/07 (26)
        
        In Reply to: RE: "a good number of the most vocal critics of the book have not read it." posted by truthseekerprime on June 09, 2007 at 11:22:31
        
        What about quoting the author's statements on this forum... - truthseekerprime 15:47:42 06/09/07 (25)
        
        In Reply to: RE: Quoting someone who doesn't like it is pretty lame in my opinion. nt posted by TomLarson on June 09, 2007 at 15:08:08
        
        ...those are more than enough to totally destroy his credibility on this.
        
        In any case, at least for my part I really don't care - I'm interested in the physics and audibility of polarity inversion, and solid theory and experiments related to that. Based on the evidence I doubt the book contains any of that, and I'm not going to go out of my way to find out.
        
        RE: What about quoting the author's statements on this forum... - TomLarson 17:35:32 06/09/07 (24)
        
        In Reply to: RE: What about quoting the author's statements on this forum... posted by truthseekerprime on June 09, 2007 at 15:47:42
        
        So be it. What's strange is that the simplest way to determine the audibility of polarity is to listen for yourself. No physics, no research, no "solid theory" no nothing.
        
        The "author" is perfectly happy having any of his statements here quoted. - clarkjohnsen 13:06:02 06/10/07 (1)
        
        In Reply to: RE: What about quoting the author's statements on this forum... posted by TomLarson on June 09, 2007 at 17:35:32
        
        They all happen to be correct.
        
        clark
        
        RE: The "author" is perfectly happy having any of his statements here quoted. - TomLarson 14:00:49 06/10/07 (0)
        
        In Reply to: RE: The "author" is perfectly happy having any of his statements here quoted. posted by clarkjohnsen on June 10, 2007 at 13:06:02
        
        Case closed!!!!!!!!!!!!!!!
        
        True, but limited. - rick_m 22:07:06 06/09/07 (21)
        
        In Reply to: RE: What about quoting the author's statements on this forum... posted by TomLarson on June 09, 2007 at 17:35:32
        
        Hi,
        I think you find out if it's true for you, your system and that one disc.
        If I'm not happy with the sound of a disc on my main system, I can just push a button and invert the signal. Most of the time it will improve it, sometimes dramatically. Again: With certain discs, I can improve my enjoyment of the sound by pressing the button. Fact Hercule! But the extant question is why?
        I think it's well worth understand better as I suspect that flipping the polarity is a gross attempt to solve what is in all likelihood a complex problem. But I appreciate having at least that much control and believe that I owe Clark for my knowing about it and probably for having the switches on the equipment.
        But even better would be to actually fix it, and to tackle that requires a detailed understanding of the mechanisms. I've read that distortion and tweeters make a difference in hearing it and my experience tentatively supports that.
        So, just listening should allow you to make the best choice (if there's a difference) between playback polarities, however it really doesn't speak to the underlying causes.
        Rick
        
        Edits: 06/09/07
        
        "I owe Clark for my knowing about it." Thank you! Then my work here is almost done. - clarkjohnsen 13:07:52 06/10/07 (0)
        
        In Reply to: RE: True, but limited. posted by rick_m on June 09, 2007 at 22:07:06
        
        But how does one reach the buffoons who won't or can't listen?!
        
        clark
        
        RE: True, but limited. - TomLarson 07:08:06 06/10/07 (19)
        
        In Reply to: RE: True, but limited. posted by rick_m on June 09, 2007 at 22:07:06
        
        Huh...well, CJ at least has given a reason or set of reasons about polarity and sound. The fact that some speakers show it up more etc etc is a problem at the reproducer end of the equipment chain and that is a different set of questions in my mind. I think from what Ive read online in the old PF he says it's a disk by disk thing and is complex vis a vis number mics etc in the recording studio. I've got the book on order and plan to read it. What I get from most of the anti-CJ posters on aa is they haven't read it and have no plans to attempt to. It's that sort of attitude that takes away any credence they may have, as far as Im concerned. If you flipped the switch (if most people did) and never heard anything, that might be a different story.
        
        "If you flipped the switch... and never heard anything..." It's all in the book! - clarkjohnsen 13:10:09 06/10/07 (0)
        
        In Reply to: RE: True, but limited. posted by TomLarson on June 10, 2007 at 07:08:06
        
        I warned about switches, as well as about loudspeakers. Many of them seem to have negligible effect, I can't explain why.
        
        clark
        
        "The fact that some speakers show it up more...that is a different set of questions in my mind" - truthseekerprime 09:07:22 06/10/07 (14)
        
        In Reply to: RE: True, but limited. posted by TomLarson on June 10, 2007 at 07:08:06
        
        Look - how do you know it's a different set of questions? How do you know you don't have something in your system that adds significant even-order distortion, thereby enhancing asymmetry in the signal and making polarity audible? How do you know that a polarity choice that sounds good to you might not sound bad to someone else on their system?
        
        You don't know that, and you can't without careful testing. That's what makes anecdotal reports of audibility useless unless and until they can be understood in a broader context.
        
        There's a pretty basic and important point here - we know that polarity is audible, in the sense that the ear can sometimes distinguish between compressions and rarefactions. We also know that musical sounds are not symmetric, and therefore if that asymmetry is large enough we can hear it. But we don't know whether that ever happens when the sound is reproduced cleanly, or only when the equipment adds distortion, or which sounds are the ones where it's audible, or whether it's transient tones or sustained tones that matter, or which polarity will sound most realistic to us, etc. etc. etc.
        
        Until those questions are answered it's just plain impossible to proceed. And they cannot be answered by listening to your stereo and noticing a difference - you have to control for all the other factors so you can isolate the root causes. No engineer - and it's engineers that build audio equipment and make recordings - is going to take this seriously until that's done. And rightly so, because there is no way they can do anything without some solid guiding principles.
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - TomLarson 13:53:49 06/10/07 (4)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by truthseekerprime on June 10, 2007 at 09:07:22
        
        Huh again...seems like your line of "argumentation" would apply to each and every aspect of hifi...analogue vs digital...tubes vs solid state...whether cables are audible, whether turntables contribute to the sound.. on and on and on....So what's so special (for you) about polarity? What I can and cannot know is not something that you get to determine by fiat.
        
        "What I can and cannot know is not something that you get to determine by fiat." He can try! - clarkjohnsen 08:20:09 06/11/07 (0)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by TomLarson on June 10, 2007 at 13:53:49
        
        Oh, he can try.
        
        And especially, can he scold!
        
        clark
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - truthseekerprime 14:22:46 06/10/07 (2)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by TomLarson on June 10, 2007 at 13:53:49
        
        What's special for me about polarity? I guess there are several reasons I'm interested in it. One is that I care about sound more than I do about electrical engineering. Cables, tubes versus solid state, analogue versus digital - those are all issues related to how best to put together a machine for accurately reproducing sound. I consider that an engineering problem, and I'm happy to let other people worry about it. Polarity I see as more fundamental.
        Another reason is personal experience - binaural recordings played through a consumer grade computer soundcard over cheap headphones sound far more real to me than the best audiophile stereo setups playing good quality traditional recordings (and I heard a ~$200,000 system recently). All those ludicrously expensive wires, ridiculously priced amps, fancy speakers, etc. can't even come close. I've never heard a stereo system that I couldn't immediately identify as such from down the hall - and yet over those headphones the illusion is so vivid I can be startled by a strange voice behind me. Why?
        I don't know the answer, but I don't think it has anything to do with vacuum tubes or cryogenically treated speaker cables. And I don't like wearing headphones much, so it would be nice to figure out why.
        
        Edits: 06/10/07
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - TomLarson 15:40:24 06/10/07 (1)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by truthseekerprime on June 10, 2007 at 14:22:46
        
        There is a bootleg lp from the 70's some time from I think an afternoon concert in Freso (maybe it was Reno) where Dylan starts singing "The Idiot Wind" and someone--presumably one of the guys on the mixing board--can be heard to say, "Oh shit, the polarity is reversed". There is a loud buzz, a moment of silence and then Dylan starts in again...
        
        Good story! See, there are those who through their obstreperousness would hide the truth from us. nt - clarkjohnsen 08:21:48 06/11/07 (0)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by TomLarson on June 10, 2007 at 15:40:24
        
        w
        
        "How do you know...?" "How do you know...?" "How do you know...?" And now, the answer: - clarkjohnsen 13:25:59 06/10/07 (0)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by truthseekerprime on June 10, 2007 at 09:07:22
        
        "You don't know."
        
        That's good to know, Teach.
        
        Say, where did you get your license to instruct?
        
        I mean, you're telling people who know more than you do about the subject, what they should be thinking. What school of education has given you the certificate to speak like that?
        
        It's just that, I wouldn't want to send my kids there, so I need to know .
        
        clark
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - unclestu52 11:48:05 06/10/07 (7)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by truthseekerprime on June 10, 2007 at 09:07:22
        
        It is interesting to examine test reports from Stereophile magazine, particularly the impulse tests and square waves (when they have them). You'll see that many, if not most, speakers display large time delays between drivers and often reverse shooting spikes. Not good, particularly when you are striving to hear relatively smaller differences in sound (in the sense that taking, say a vocal in reversed polarity, is not really going to totally disrupt the cognisant perception of the words).
        
        Couple this 'misaligned' drivers type of execution with a front mounted port or a passive radiator, or even a woofer firing on the side and you have compounded the problem if not merely added to the potential to do so at certain frequencies.
        
        These distortions actually cloud the audibility of polarity and phase. I liken it to the old Instamatic Cameras. You never had to focus because it never was in focus to begin with. With a good SLR, you know if the picture was in or out of focus immediately at viewing the prints.
        Although he never mentioned polarity issues, at one point in time Ray Kimber was also dabbling with speaker crossovers as well as with recording techniques. When I asked him about this, his reply was that was where the majority of problems seemed to be occurring in the audio chain. Odd (well not really) that it would occur at the extreme wends of the chain.
        
        There are single stereo mike recordings so that ameliorates the issue of heavy multimiking and the phase issues that can occur there. There are single driver speaker systems too, and while there are phase shifts at the frequency extremes, I am wondering if much of the appeal of such systems is the fact that polarity is maintained, for the most part,
        throughout the mid range for most designs.
        
        A simple test would be to measure and record a complex (OK two frequency)
        waveform through a single driver system and then compare it to a multiple driver system. Actually a single impulse test would also work fine, in my thinking.
        
        As you have pointed out, since the brain does major filtering and correlation, that can not be eliminated from the equation. However, if you are interested and wish to confirm the facts from a scientific point of view, the above procedure will probably go a long way in the search for a solid foundation.
        
        I honestly wish I lived closer to you in order to aid the investigation. We have our differences in thinking, but you have demonstrated quite eloquently the desire to investigate and to learn and to establish a solid empirical body of proof. I learn a lot from my mistakes, but you seem to be willing to take the procedure one step closer to resolution through your own experimentation and not simply rely on evidence from the past.
        
        Good luck and carry on,
        
        Stu
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - TomLarson 13:58:20 06/10/07 (6)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by unclestu52 on June 10, 2007 at 11:48:05
        
        The list of problems you invoke regarding speakers that according to you (if Im reading this right) make determinations of polarity difficult if not impossible should also make any other distinctions equally impossible. If the hi end speakers we listen to are in the class of instamatic cameras, we are in trouble,,,, cause there aint no nikons around that the average audiophile just hasn't heard about, given that he shops, in your picture at target....
        
        Sigh - unclestu52 22:45:16 06/12/07 (0)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by TomLarson on June 10, 2007 at 13:58:20
        
        Like I say, learn what Stereophile's measurements are really revealing rather than just reading the text.
        
        Think again now. If perfect frequency response and perfect timing, phase and polarity were the goal of every speaker system, shouldn't there be a convergence at a certain price, say at $50K? At a $100K, there ought to be, I would think, or rather, I would like there to be.
        
        Speaker manufacturers, to a large degree, are not interested in designing a truly neutral speaker system. You can regard them as being good chefs: capable of creating an interesting product but aimed specifically at a certain market and taste. They are interested in capturing a certain market sensibility, and because music is subjective, there are many flavors to sonic 'tastes.'
        
        A phase correct speaker need not be expensive: take the Vandersteen line, and the now defunct Ryan Acoustic line. If accuracy is your goal, then phasing and time alignment is of importance. If not, then polarity won't mean anything and is of no importance at all. If most listeners are not aware of the effects of polarity and phasing, then a truly neutral speaker system would be difficult to acquire by most.
        
        Why do listeners constantly harp about system 'synergy'? You can measure most electronics and pretty much predict how they should sound. There exists a barrage of tests which one can perform on most electronics. Yet those identical tests performed on a speaker will come to very different conclusions by most reviewers. I've heard many an electronic engineer grumble that the tests with what is deemed acceptable results for speakers would have them laughed out of business almost immediately if their electronics displayed the same results.
        
        Now, if you were to say to me that polarity is of no consequence, then fine, speaker phase and timing errors are of no importance. But if you told me that you are also looking for sonic realism and neutrality, and can not seem to find it in many products, then an understanding of the phenomena is of crucial importance at both the beginning of the chain and at the end. If you dismiss the importance of determining the causality of the issues but still proclaim that polarity is an issue, then enlightenment is not to be had, no matter how long and loud you exclaim. That is the gist of my dissatisfaction with CJ. There exists no program for change and/or enlightenment.
        
        Now, in making those statements above, I have probably made a lot of enemies, or at least been placed on many 'black' lists. Perhaps a reviewer needs to be more 'diplomatic' in order to retain his job and still be welcomed at CES and other audio functions. There certainly exists a certain commercial value in denying the effects of phase and polarity. If you spent even, say, $25K on a speaker, and then discovered it had design flaws, how would you feel?
        
        Stu
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - truthseekerprime 11:48:22 06/11/07 (3)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by TomLarson on June 10, 2007 at 13:58:20
        
        Not necessarily. What unclestu is pointing out is that speakers by their very nature distort phase information. Any driven oscillator - mechanical or electrical - vibrates out of phase with an applied driving force. There is a time delay between the force being applied and the response - which is nothing but plain old inertia. That time delay is a function of frequency, which means the time-domain response of a speaker is typically very different from the signal driving it.
        
        Speakers are designed to produce as flat as possible a frequency response, with little regard for phase response. There's a very very good reason for that - we are close to deaf to phase distortions, but very sensitive to frequency response distortions. A speaker with terrible phase response may still be very resolving in many other ways - there's no reason to expect it to be "out of focus" for anything other than phase information.
        
        This is yet another reason why worries about polarity can't go anywhere without a better understanding. What aspects of time-domain distortion should we worry about? Which are audible? How do they affect the illusion of real acoustic sound we're striving for?
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - TomLarson 17:47:28 06/11/07 (2)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by truthseekerprime on June 11, 2007 at 11:48:22
        
        If at least some state of the art speakers produced right now aren't up to the task, then nothing will be. I don't know which ones, but you seem to dismiss them all. And I still find that absurd. In the world of hi end audio, especially in its upper reaches, the "instamatic" label just doesn't apply.
        
        RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" - truthseekerprime 20:55:38 06/11/07 (1)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by TomLarson on June 11, 2007 at 17:47:28
        
        All speakers distort phase by inducing time delays, but some are much worse than others. The best in that regard are single-driver speakers without crossovers, like headphones. Actually as of pretty recently it's become possible to compensate for time delays using digital signal processing, but there aren't many systems that incorporate that.
        
        I don't have much use for their reviews on the whole, but Stereophile does take pretty thorough measurements. Look at figure 7 here - that's the response of a $65,000 speaker to a step function. See what I mean?
        
        http://stereophile.com/floorloudspeakers/507peak/index4.html
        
        Here's a single driver speaker with no crossover - that's about as good as it gets.
        
        http://www.stereophile.com/standloudspeakers/107fuj/index4.html
        
        Finding some that don't cut it doesn't mean that none do. - TomLarson 22:00:25 06/11/07 (0)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by truthseekerprime on June 11, 2007 at 20:55:38
        
        But enough is enough. Hope you find the "hard science" or whatever it is you claim to be looking for.
        
        "If the hi end speakers we listen to are in the class of instamatic cameras..." Oh MAN! - clarkjohnsen 08:18:31 06/11/07 (0)
        
        In Reply to: RE: "The fact that some speakers show it up more...that is a different set of questions in my mind" posted by TomLarson on June 10, 2007 at 13:58:20
        
        Suddenly I feel a chill wind...
        
        No wonder those dudes are unable to command the resolution (and not a huge lot is needed) to obtain polarity awareness.
        
        Or, as you suggest, much awareness at all.
        
        Pity these comments appear so far down the thread. Why don't you introduce it as a new topic huh? Huh?
        
        clark
        
        RE: True, but limited. - rick_m 09:01:41 06/10/07 (2)
        
        In Reply to: RE: True, but limited. posted by TomLarson on June 10, 2007 at 07:08:06
        
        Actually, I haven't read the book either... However I'm such an old geezer that I used to belong to OTS and got the paper PF. I either heard about it there or in Stereophile. Whichever, I don't think I've ever seen a reference to it that didn't mention CJ, he has done a yeoman's job of rousing the rabble.
        
        I would love to understand it in more detail. I'm an electronics guy and I like to see correlation between wiggles on the scope or spectrum and what I hear. When you get the book let me know if it has anything quantitative in it, if so I'll spring for a copy.
        
        This whole thread has really sparked my interest in reexamining this issue. I'd grown complacent with merely pushing the button...
        
        Regards, Rick
        
        Imagine that! We have an inquisitive soul! Certainly a pleasant change. I mean... - clarkjohnsen 13:17:02 06/10/07 (1)
        
        In Reply to: RE: True, but limited. posted by rick_m on June 10, 2007 at 09:01:41
        
        ...someone with a soul!
        
        One has to worry about my old-maidish, persnickety antagonists -- constantly instructing me as to this and that. I don't hear any music in their voices, and they all seem out of phase. ;-)
        
        clark
        
        How do you know you're in correct phase? (NT) - unclestu52 12:41:24 07/11/07 (0)
        
        In Reply to: RE: Imagine that! We have an inquisitive soul! Certainly a pleasant change. I mean... posted by clarkjohnsen on June 10, 2007 at 13:17:02
        
        Stu
- RE: Some interesting tests, but this is all irrelevant. Give me the ability to switch and I will decide myself - truthseekerprime 07:40:51 06/06/07 (1)
  Of course I wouldn't. It's none of my business what people do with their systems, nor would I want it to be. If someone thinks their system sounds better when they put a photo of it in the freezer, that's fine with me too. But I'm interested in finding out what the basis is for that belief - is it a real physical effect which one can quantify, or is it psychological?
  In this case we know there is a real effect at least for certain special cases, and I want to know how far that extends.
  
  Edits: 06/06/07
  - I know it is not psychological although that too is quantifiable. The interesting question is why producers - Norm 19:02:10 06/08/07 (0)
    care so little and of course how to make a inverting switch without another amplifying stage.
Some very good thoughts on polarity! - unclestu52 21:41:58 06/04/07 (3)
I believe you have hit the nail directly on the head on several points in explaining the phenomena. I believe your reasoned thoughts go much further than most comments in explaining the audibility of polarity changes. To be sure, I had never really considered the ear as being the cause of the 'half wave' rectification you describe, although I was definitely aware of the perception of it.

As for the audibility of polarity in actual music, it is audible, simply because the vast majority of sounds are asymmetrical, particularly in their attacks. It is primarily audible in the wind instruments and the percussion. You can measure a definite difference by using a peak reading SPL meter.

If you have every played a wind instrument or know their sound well, there is distinct difference between a tongued attack and a breath attack. In a tongued attack, the player uses his tongue to stop the air column from being actuated, while a breath attack has the player simply exhale till the air movement excites the air column. I played too long not to be able to discern the difference, but I can understand a layman who would be unfamiliar with the concept and thus not be able to hear it.

I do not hear it as a pitch change, however, but I do hear the overtones generated as being in a different 'mix'. If the overtones are generated from the same initial starting point, then the initial compression waves of the overtones are overwhelmed by the fundamental tone. Inverted, the harmonics slightly lead the fundamental. This is something I hear particularly in the held tones of a piano, as the strings are allowed to 'ring'.

Despite some disagreements from others, I find your post a most welcome addition to the subject of polarity and one that provokes more thought and an advancement on the subject.

A sincere thank you,

Stu
- RE: Some very good thoughts on polarity! - truthseekerprime 12:14:02 06/05/07 (2)
  Thanks, Stu. Actually I play a brass instrument, so I know quite well the difference between a breathed and a tongued attack. When I get a chance I'll try recording both and see how the waveforms look.
  - RE: Some very good thoughts on polarity! - unclestu52 12:49:57 06/05/07 (1)
    While you can record both attacks, I would suggest just recording a tongued attack and playing it back with the polarity correct and then inverted. Just that intial attack will be audible, at least for me, and that would settle the issue of polarity being audible in music.
    
    Stu
    - RE: Some very good thoughts on polarity! - truthseekerprime 14:06:13 06/05/07 (0)
      OK, I'll give it a shot. I agree that if that's audible it more or less settles the issue. I'll also try it with a good trumpet music CD, as my recording abilities/equipment are not exactly state-of-the-art.
      
      However Greiner and Moulton tried this under near-ideal conditions with clarinet, trombone, and some other wind instruments - and the results were all negative.
RE: some thoughts on polarity - truthseekerprime 10:41:27 06/04/07 (20)
By the way - I mentioned this in passing in my post - but (as Axon has emphasized elsewhere) reflections off hard surfaces invert the phase of sound waves. Yet another reason why even the concept of absolute polarity in recorded music is meaningless, especially when one considers that the listening room will have its own set of reflections.

This doesn't mean polarity reversal can't audible, but it's yet another reason that there can't be such a thing as a "correct" polarity choice, either during mastering or during playback.
- "Reflections off hard surfaces invert the phase of sound waves." Really?! - clarkjohnsen 09:34:46 06/05/07 (6)
  Stanley Lipshitz would beg to differ with you -- and I have it from him in writing!
  
  "Yet another reason why even the concept of absolute polarity in recorded music is meaningless." Substitute the *opposite* word -- "meaningful" -- and my out-of-phase antagonist would have it right. Al last.
  
  clark
  - Ask him about reflections off openings in the room... - truthseekerprime 12:16:39 06/05/07 (5)
    ...and if you didn't know they existed, learn something about waves.
    - That wasn't the topic and you know it. You were WRONG; admit it, don't weasel out. - clarkjohnsen 12:23:26 06/05/07 (4)
      You say you seek the truth, but when you find it contradicts your views you change the subject.
      
      clark
      - I'll admit I was wrong, if that makes you feel any better. -nt - Axon 21:24:37 06/05/07 (0)
        
        In Reply to: RE: That wasn't the topic and you know it. You were WRONG; admit it, don't weasel out. posted by clarkjohnsen on June 05, 2007 at 12:23:26
        
        .
      - Umm.... - truthseekerprime 12:31:49 06/05/07 (2)
        
        In Reply to: RE: That wasn't the topic and you know it. You were WRONG; admit it, don't weasel out. posted by clarkjohnsen on June 05, 2007 at 12:23:26
        
        ...did you bother to read anything I wrote? Yes, I was wrong about that, and I admitted it already. I based it on a major physics website which was flat-out incorrect. After being challenged on it, I though about it, checked a more authoritative reference, realized my error, and posted a correction. If you'd like I'll explain why the error was probably made in the first place, but I'm sure you're not interested.
        
        You see (unlike some people) I make mistakes occasionally, and even learn from them. You might find it useful to think about that - but I know you won't.
        
        "Did you bother to read anything I wrote?" Regrettably, yes. - clarkjohnsen 12:54:30 06/05/07 (1)
        
        In Reply to: RE: Umm.... posted by truthseekerprime on June 05, 2007 at 12:31:49
        
        The most obstreperous, boring... But indeed, a couple of hours ago, buried down in the thread, was your admission.
        
        clark
        
        At the very least,, - unclestu52 18:45:30 06/05/07 (0)
        
        In Reply to: RE: "Did you bother to read anything I wrote?" Regrettably, yes. posted by clarkjohnsen on June 05, 2007 at 12:54:30
        
        he could admit an error. I do not recall any incident where you have admitted an error, and even pointing out an error in spelling got a vigorous defense.
        On the subject of polarity, you have been your worse enemy, making an admission that polarity is audible a stigma upon the person admitting that he can hear it. A bit of humility and a bit of cooperation would advance the issue a lot further. A good dialogue, rather than one liners, would further the understanding also. If you can not or choose not to engage in a serious dialogue, then no advancement is really possible. Name calling and insults are no way to stage a dialogue.
        
        I find Truthseeker to be much more open minded and open to new ideas than many others. He will go much further than you ever will to establish the audibility of polarity.
        
        That is the pitiful reality of your attempt at arguments. And that view is shared by many, many others.
        
        Stu
- RE: some thoughts on polarity - rick_m 19:50:34 06/04/07 (12)
  Hi,
  
  You said that "reflections off hard surfaces invert the phase of sound waves", which doesn't seem correct to me. I rather thought hard surfaces had a higher acoustic impedance than air and therefore reflect sound in-phase, not inverted.
  
  Rick
  - reflected waves - truthseekerprime 21:21:45 06/04/07 (11)
    It's true that a dense surface like a wall has higher acoustic impedance than air, but that means a wave in air that reflects off that surface will have inverted polarity.
    
    Look here for example:
    
    http://www.physicsclassroom.com/Class/sound/u11l3c.html
    http://www.kettering.edu/~drussell/Demos/reflect/reflect.html
    
    or here for some great animations:
    
    http://www.gmi.edu/~drussell/Demos/waves/wavemotion.html
    - RE: reflected waves - rick_m 23:28:29 06/04/07 (10)
      Thanks for the interesting links. Finally figured out how to turn on animation in the browser and that perked them up. I'm thinking that this one you referred to: http://www.physicsclassroom.com/mmedia/waves/free.html kinda applies here. Although it's showing a transverse impulse hitting an open end, I think the same condition applies to a longitudinal wave hitting a closed end. If you take the vertical displacement in the animation as the pressure of the longitudinal wave it looks good.
      
      I believe confusion ensues when trying to think of longitudinal waves using a transverse mental model. I pawed around on the web and found a site that seems to apply, check out:
      
      http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reflec.html
      
      They even have a scheme to visualize the phase of longitudinal waves with a string analogy.
      
      Here's one that also applies although it's sonar: http://interactivesonicspaces.interfaculty.nl/ferenc_teglas/reflection.htm
      
      I'm hanging on to my belief that sound waves do NOT invert when bouncing off of solid objects.
      
      So, can we infer that this means that absolute polarity is twice as important when listening in a reflective environment?
      
      Regards, Rick
      - "I'm hanging on to my belief that sound waves do NOT invert when bouncing off of solid objects." - truthseekerprime 07:59:23 06/05/07 (6)
        
        In Reply to: RE: reflected waves posted by rick_m on June 04, 2007 at 23:28:29
        
        Your belief is correct - what I said before was wrong. I apologize for that - one should never believe anything one reads on the internet, including this sentence... in fact I'm going to email the administrator of that site. It's pretty inexcusable to get that wrong on a website devoted to helping high-school kids learn physics!
        
        Now, how can we see what happens to sound waves bouncing off a barrier? The easiest way is to simply visualize a compression pulse traveling towards a wall. If no energy is absorbed into the wall, the pulse must bounce off with the same amplitude. And because the number of air molecules is preserved during the bounce, the reflected pulse must also be a compression pulse.
        
        More formally you can just solve the equations of motion, subject to the boundary condition that the air displacement at the wall is zero. That boundary condition is like a fixed end string, for which the reflected pulse is inverted. In other words there's a node in the displacement at the wall. But the pressure is the derivative of the displacement with respect to position, and so the reflected pressure wave has the same polarity as the incident wave, and there is an anti-node of pressure at the wall.
        
        What does this mean for the issue at hand? Well, as I mentioned before, the moment there is more than one source of sound and more than one mic per channel you can't preserve polarity when you mix the mic channels. Furthermore the polarity of sound waves generally changes as a function of position. For example the polarity of a dipole radiator reverses as you move in a circle around it - so reflected waves from one side are of opposite polarity as reflected waves from the other. So only if we record one monopole radiator with one mic is there a correct phase which it makes sense to preserve, at least as far as I can see.
        
        Wow! I'll own up to being wrong too. - Axon 21:23:17 06/05/07 (1)
        
        In Reply to: RE: "I'm hanging on to my belief that sound waves do NOT invert when bouncing off of solid objects." posted by truthseekerprime on June 05, 2007 at 07:59:23
        
        I read back on what I had originally written on HA about room reflections, and in hindsight, I completely misunderstood what I was responding to, as well as getting my references wrong. Glad to know that the situation is more nuanced than I had thought.
        
        Thanks Rick and truthseekerprime!
        
        Ah shucks... - rick_m 22:35:34 06/05/07 (0)
        
        In Reply to: RE: Wow! I'll own up to being wrong too. posted by Axon on June 05, 2007 at 21:23:17
        
        I haven't read your postings on the subject, but am pleased that you found our exchange helpful. But as my psych prof used to say, "there's no stars in being right and no stigma in being wrong". I only happened to notice that it seemed backward because I'm used to working with RF transmission lines.
        
        My thanks to you both for the gracious responses, it's great fun being able to kick things around and learn from one another.
        
        Long Live Home Audio!
        
        Rick
        
        I agree... - rick_m 09:04:47 06/05/07 (3)
        
        In Reply to: RE: "I'm hanging on to my belief that sound waves do NOT invert when bouncing off of solid objects." posted by truthseekerprime on June 05, 2007 at 07:59:23
        
        I noticed our postings crossed in the mail, as it were. But our stories are the same.
        
        Multi-miking is the bane of recording. I think suffering all the problems that ensue with a single microphone are worth it. Frequency response is way overrated in my book as I believe that impulse response is far more important to ultimate satisfaction. As you've stated, it usually gets lost in mix-downs.
        
        As far as reflections go, I don't think that they nullify the importance of correct phase. As you mentioned earlier, consider binaural recording, you end up recording the reflections, but you would also hear them if you were there. Mixing together Mics. from various places is unnatural and wipes out essential temporal information if their levels are anywhere close.
        
        Regards, Rick
        
        RE: I agree... - truthseekerprime 12:44:52 06/05/07 (2)
        
        In Reply to: RE: I agree... posted by rick_m on June 05, 2007 at 09:04:47
        
        It's certainly true that binaural recordings played through headphones have by FAR the most realistic soundstage I've ever heard. It's really eerie how realistic they sound, even on medium to low quality phones.
        I think the future is probably sophisticated digital processors which compensate for the listening environment and speaker system and adjust the phase etc. appropriately. Suppose we replace CDs with a new digital format that contains information about the recording venue, including multiple tracks recorded by mics at different positions (that information is usually kept by record companies so they can make new mixes and re-release them). There would be a digital pre-amp that calibrates itself once to the speakers and the listening room with a few measurements, and then processes the recording based on that information and the information in the digital file so as to produce the most realistic result at the listening position.
        Not simple, but well within reach of current technology, I would say.
        
        Edits: 06/05/07
        
        RE: I agree... - rick_m 16:32:53 06/05/07 (1)
        
        In Reply to: RE: I agree... posted by truthseekerprime on June 05, 2007 at 12:44:52
        
        I believe you correct both in the potential direction and that it's within reach of current technology. I suppose we would record everything as dry as possible and convolve it with the forum coefficients upon playback. But how many people care enough to bother? Surely not the music business. Plus the additional processing, if not done to "audiophile" standards could degrade the final result.
        
        Perhaps a simpler approach would be to just standardize on binaural (with defined polarity of course). There are orders of magnitude more people listening with headphones now than there were 20 years ago and they could get great sound with no processing. Our home stereos could concentrate on delivering that sound to our ears sans headphones.
        
        Actually for me, just simple stereo or even mono, can be very satisfying if it's recorded and mastered well. Wish more were...
        
        Regards, Rick
        
        RE: I agree... - unclestu52 23:46:54 06/05/07 (0)
        
        In Reply to: RE: I agree... posted by rick_m on June 05, 2007 at 16:32:53
        
        It is interesting that you two are questioning the microphone techniques. I do believe it further advances an understanding of the issue of polarity.
        
        In the case of many 'pop' recordings, I believe you'll find your first statement to be true. Mikes are set up very close to, and actually within the instrument at times. Mikes are within a drum kit, and are often clipped to the bells of the various instruments, and thus they are often actually employing what you are advocating (in saying that the recording should be 'dry' as possible.
        
        As far as orchestral recordings or large scale ensembles, the distance does become critical. Binaural, or single stereo mikes are very good and avoid most issues. Decca, as you are probably aware of, used a 'tree', a 'T' shaped jig upon which the various mikes were mounted with different patterns depending on what was required. Here, the mikes employed were roughly about 3 to 4 feet apart at the maximum.
        
        TSP (truthseekerprime) is very correct in stating that the distance between the mikes present a potential problem in recreating a phase correct experience. Audio wavelengths can be very long, over 30 feet in length and also very short. Here a cue can be determined by the average distance between a set of human ears: say about 6 inches or so.
        
        However, the situation of recording live is somewhat ameliorated by the triangulation of the placement. In the case of the Decca 'tree' the mikes are placed, say, 40 feet away from the ensemble. While the mikes may be a slight distance apart from each other, they are roughly equidistant from the ensemble itself. The result is manifested in the sound obtained: things are more coherent and more consonant with what you hear in real life. Use of a cardioid pattern will eliminate a certain amount of crosstalk between the mikes, which can help.
        
        In contrast, listen to the Decca recorded Phase Four albums. They are heavily multimiked and the perception is that you are sitting within the orchestra. Many of the classic RCA's have similar sound, though maybe not as apparent. The highly lauded RCA Reiner/Scheherazade (TAS super disc list) falls in that category. I believe only the first three stereo recordings were minimally miked: The Reiner/Zarathustra [LSC 1806], the Fiedler/Gaite Parisienne [LSC 1817]and the Munch/Daphnis and Chloe [LSC 1893]. These are minimally miked recordings and sound very different from other RCA's which typically use 6 to 7 mikes.
        
        In the case of the Scheherazade, the listener can hear anomalies in the three dimensional soundstage presented. The various solo instruments zoom to the foreground and when their solo is over, retreat back into the orchestral mix.
        
        The most interesting microphone technique currently employed is the one designed and utilized by Ray Kimber. His operating principle was to try and recreate the typical loudspeaker set up but to avoid the phase issues by having mikes set up say 10 to 12 feet apart, the typical distances most speakers are placed apart.
        
        It is not an inexpensive set up, but it has fascinating results and is very realistic. The set up is only available at Weber State auditorium, IIRC, but the recordings there are superb, although not all the University's music students may be quite deserving of the quality of the recordings. In addition, Ray employs several other 'tricks' in order to get very realistic recordings. I've seen him advertise the sample discs he has on AA with all proceeds going to the Weber State Music program. If you have not heard his recordings I would highly encourage you to try them. The technique obviously will not be universally adopted, but they remain as a fascinating experiment in the recreation of a live event, and a very realistic one at that.
        
        Stu
      - RE: reflected waves - truthseekerprime 05:18:38 06/05/07 (2)
        
        In Reply to: RE: reflected waves posted by rick_m on June 04, 2007 at 23:28:29
        
        I'll sit down later today and calculate this. For the moment, read this from the link in my previous post, which very emphatically states that sound waves reflected off of hard surfaces are polarity inverted:
        
        http://www.physicsclassroom.com/Class/sound/u11l3c.html
        
        These principles of free and fixed end reflection can be applied to sound waves. Though a sound wave does not consist of crests and troughs, they do consist of compressions and rarefactions. If a sound wave is traveling through a cylindrical tube, it will eventually come to the end of the tube. The end of the tube represents a boundary between the enclosed air in the tube and the expanse of air outside of the tube. Upon reaching the end of the tube, the sound wave will undergo partial reflection and partial transmission. That is, a portion of the energy carried by the sound wave will pass across the boundary and out of the tube (transmission) and a portion of the energy carried by the sound wave will reflect off the boundary, remain in the tube and travel in the opposite direction (reflection). If the end of the tube is "open" or uncovered such that the air at the end of the tube can freely vibrate when the sound wave reaches it, then the behavior at the boundary resembles free end reflection. There is no inversion of the disturbance when reflecting off the open end (uncovered end) of a cylindrical tube. That is, if a compression is incident towards an open-end, it will reflect and return as a compression. Similarly, if a rarefaction is incident towards an open end, it will reflect and return as a rarefaction. The opposite occurs if the end of the tube is "closed" or covered up. If the end of the tube is "closed" or covered, then the air at the end of the tube is fixed and cannot freely vibrate when the sound wave reaches it. In this case, the behavior at the boundary resembles fixed end reflection. There is inversion of the disturbance when reflecting off the closed end (covered end) of a cylindrical tube. That is, if a compression is incident towards an closed end, it will reflect and return as a rarefaction. Similarly, if a rarefaction is incident towards an closed end, it will reflect and return as a compression.
        
        The behavior of sound waves at open ends and closed ends will become important Lesson 5 during the discussion of musical instruments. Many musical instruments operate as the result of sound waves traveling back and forth inside of "tubes" or air columns. These waves reflect at either a closed end or an open end of the air column; and the fact that inversion occurs at a closed end will have a huge impact on the numerical pattern of frequencies produced by such instruments.
        
        RE: reflected waves - rick_m 08:31:33 06/05/07 (1)
        
        In Reply to: RE: reflected waves posted by truthseekerprime on June 05, 2007 at 05:18:38
        
        Well, he may be emphatic, but then so are politicians... I still think he's got it backward. Imagine an audiophile's wife getting to the mailbox first and opening the Visa bill. Seeing what his new preamp cost, she trots into the listening room and shoots him.
        
        The pistol causes a rapid increase in the room's air pressure which propagates as a positive wavefront. When it strikes a wall (a high Z), it can't go any further and the pressure builds up at that point which in turn produces a positive wavefront which propagates outward back into the room. It reflects in phase.
        
        In her haste she left the door open so when the positive wavefront going in that direction reaches it, it can escape and most of it does rapidly decreasing the net air pressure and causing a negative wavefront to propagate back into the room. It's a low impedance and reflects out of phase.
        
        The moral is that high impedances reflect in phase, low impedances out of phase and that a new preamp can have hidden costs.
        
        Regards, Rick
        
        You're correct - see my post above - truthseekerprime 08:59:50 06/05/07 (0)
        
        In Reply to: RE: reflected waves posted by rick_m on June 05, 2007 at 08:31:33
        
        x
"50 years of anecdotal evidence hasn't gotten anyone to take this seriously." Seriously? You're a laff riot. - clarkjohnsen 09:55:58 06/04/07 (14)
"Anyone"? Anyone?!

Richard Heyser

Stanley Lipshitz

Peter Tappen

David Stodolsky*

John Atkinson

Bert Whyte

Tim di Paravicini

John Curl

Peter Butt

Ed Long

John Roberts

James Boyk

Peter Moncrieff

Neil Levenson

Dave Wilson

Harry Pearson

Stephen Temmer

Doug Sax

Lars Fredell

___

Oh one could go on and on, but clearly these gentlemen's views do not matter to James Johnston nearly so much as do those of... James Johnston.

Like Tom Larson, I wonder what his point is -- apart from excusing his apparent inability to distinguish polarity.

clark

* "Monaural phase effects can significantly affect the quality of a perceived sound... [From our experiments] it is concluded that absolute phase error is more detectable than 11.5% intermodulation distortion."

-- IEEE Transactions on Audio and Electroacoustics , September, 1970. (A peer-reviewed journal outside the ken of our soi-disant "truthseeker", who also refuses to seek out the one sourcebook on this vital audio topic.)
- A very simple question - unclestu52 12:17:05 06/08/07 (0)
  In examining all the names you have mentioned, and since many participate on this site, why do you believe that very, very few of them lend their support to your position?
  
  Lars wrote an article for a magazine, now defunct. I am not aware if he participates here. John Curl says he can hear polarity, but what of the others? I have not really seen Harry Pearson mention it in his reviews and at one time I had and still have every issue up to the point that Harley became editor and there was a change in format. Klaus points out polarity issues evident with Sterophile's test reports, but no one there comments about the effect on sound. Why is this, you suppose?
  
  Perhaps your antagonists are correct: polarity is not audible. The list of names and many of their writings seems to justify their statement (out of respect, let us EXCLUDE those who have passed on, as they are not here to defend themselves). Many have read your book, too, or at least that is what is said. Is there a lack of understanding, and, if not, why is there a general sense of apathy among most reviewers and writers?
  
  In light of this general malaise afflicting the 'movers and shakers' of the audio community, how does your position and explanations fit in to promoting knowledge and understanding?
  
  Rude Stu
- RE: "50 years of anecdotal evidence hasn't gotten anyone to take this seriously." Seriously? You're a laff ri - truthseekerprime 10:23:05 06/04/07 (9)
  Every published source you pointed me to sa far FAILED to find evidence for polarity audibility in music, despite your claims. I'm not going to waste my time with more. The quote you give above is (not surprisingly, coming from you) very vague - it might refer to phase distortions rather than polarity reversal, it might refer to test tones rather than music, it might refer to two null results, neither of which is statistically significant (but one closer than the other).
  - RE: "50 years of anecdotal evidence hasn't gotten anyone to take this seriously." Seriously? You're a laff ri - john curl 13:30:01 06/04/07 (1)
    Truthseekerprime, try it for yourself. That Is ALL that matters in reality. If you CAN'T hear any difference, then for you, it is not important. I personally hear very little difference, BUT I often hear a difference. Some music is more obvious than other music. Usually asymmetrical waveforms like some human voices or musical instruments are more obvious. Trash from a MP-3 player might not be as much, EXCEPT to a well trained listener like Clark.
    As far as provable reality is concerned: I cannot PROVE to you that the Earth goes around the Sun. It doesn't appear that way when I go outside. It is much the same thing. IF you want absolute proof, don't come to a website such as this and expect it.
    - RE: "50 years of anecdotal evidence hasn't gotten anyone to take this seriously." Seriously? You're a laff ri - truthseekerprime 13:59:00 06/04/07 (0)
      I have tried it. That's what my posts were about :-).
      
      No one is asking for absolute proof - just reasonable discussion. In the case of the earth around the sun, there's a pretty good theory, and that's what makes us confident we know what we're talking about. The issue here is to try to develop a theory, so that we can answer questions like why is polarity sometimes audible, what makes it more so, is there a notion of correct polarity, why do some people hear it and some not, etc.
  - More lies. To them it was *all* about music, every name named. - clarkjohnsen 10:30:40 06/04/07 (6)
    "It might... it might... it might..."
    
    But it WASN'T.
    
    This errant poster is grasping at the straws of false hypotheses... but who can blame him, it's all he has left -- virtual dust in the wind.
    
    clark
    - caught yet again - truthseekerprime 12:09:57 06/05/07 (2)
      The minute anyone investigates any quote you give to support your case, it falls apart.
      
      If you wanted to convince the world that absolute polarity is meaningless and to be ignored, you could hardly do a better job. Congratulations!
      - By now you've figured out ... - Dave Pogue 12:47:57 06/05/07 (0)
        
        In Reply to: RE: caught yet again posted by truthseekerprime on June 05, 2007 at 12:09:57
        
        ... that Clark would rather whine, posture, and pontificate than actually contribute anything useful to a polarity discussion. But he's entitled, 'cause he "discovered" it, as he'll never let anyone forget.
      - More lies, followed by more and more lies. Is it congenital, or constitutional, with you? nt - clarkjohnsen 12:14:59 06/05/07 (0)
        
        In Reply to: RE: caught yet again posted by truthseekerprime on June 05, 2007 at 12:09:57
        
        fc
    - Why is it, - unclestu52 21:16:36 06/04/07 (0)
      since Dave Wilson can hear polarity inversion, that he mixes polarities with his speakers?
      
      Stu
    - RE: More lies. To them it was *all* about music, every name named. - truthseekerprime 10:34:21 06/04/07 (1)
      And I'm supposed to take your word for that? Sorry, but you've lost all credibility after twice misrepresenting research on this subject, and I simply don't trust what you have to say about it.
      - "You... misrepresent[ed] research on this subject." A TOTAL LIE. - clarkjohnsen 10:46:35 06/04/07 (0)
        
        In Reply to: RE: More lies. To them it was *all* about music, every name named. posted by truthseekerprime on June 04, 2007 at 10:34:21
        
        And an actionable calumny. This poster, besides being a serial prevaricator, clearly does not wish to learn from his betters, or from anyone.
        
        How very... jj!
        
        clark
- God, Clark, get a grip. He's not jj. -nt - Axon 10:20:15 06/04/07 (2)
  .
  - Elsewhere it was stated, without contradiction, that he is. Anyway... - clarkjohnsen 10:24:29 06/04/07 (1)
    ..that doesn't change a thing I said.
    
    clark
    - RE: Elsewhere it was stated, without contradiction, that he is. Anyway... - truthseekerprime 10:35:39 06/04/07 (0)
      I simply don't bother to contradict all the false things you say - I realized rather quickly that it was pointless, and I have better things to do with my time...
My favorite audiophile hobby quote: "We argue so violently because the stakes are so low." - Enophile 19:44:50 06/03/07 (10)
Hi,

I enjoyed your post.

For me, the issue is pretty non-threatening, either way.

We can choose gear that offers polarity switching, if we like, and then, we can play with the switch and decide which sounds "better."

I say better, because our goals are often idiosyncratic rather than definitive.

If someone says he can hear that difference, great! His hobby just got more enjoyable.

It's when the issue crosses over from being one fun aspect of a multifaceted hobby into being someone's universally applicable fetish that must be acknowledged with every audio observation that it can become a social headache.

It's the same with people of faith who claim that only their own fetishized way of "objective" worship is the one true path - they all take a specific personal opinion and then demand everyone worship at the same altar. It doesn't make sense in either realm.

It's also a bummer when someone with a pet audio fetish keeps boiling discussions of other aspects of the hobby down to his own fetish, every freakin' time. Audio doesn't lend itself one trick ponies.

"Polarity" and "comb filtering" often get turned into monomaniacal issues, to the detriment of discussing important things, like how pictures in freezers affect our audio gear!

(Purely a joking example of a controversial issue.)

Thanks for your post, it was fun to take the time to think about what you said.

Oh, and back to the subject at hand:

I've got gear that will switch, and there are discs where I can readily discern a difference. For some music playback, the switch will sound like the speakers are better "coupled" (for want of a better word) to the room. I feel like there is better transient "oomph" and imaging seems to become more forward and "sharp." Plus, these “findings” follow me from system to system when I try it at home. However, sometimes, I can be "in the mood" for the opposite setting on the same disc! I guess "better" can vary from situation to situation.

(I listen to Apogee two-way ribbons on one system, electrostats on another, and Lowthers on another, so maybe my preferences are a little "polarity influenced" as evidenced by my search for speakers with minimal crossover "issues.")

Also, I often wonder of the switches are doing only what they claim to be doing and not just adding a dB or two of gain or introducing some other anomaly that I am calling "polarity!"

I'm so cynical, I don't even trust the switches to be accurate!

OK, that's enough. Thanks again for the post. Happy listening!
- Uh--that's a steal from Henry Kissinger, believe it or not.... - Bill Leebens 18:24:53 06/07/07 (0)
  ...commenting once on university politics, Kissinger remarked that such things often became unbelievably vicious "because absolutely nothing is at stake."
  
  FWIW.
  
  Cheers, Bill
- Good Post -I agree NT - lancelot 07:46:34 06/04/07 (8)
  NT
  - Switches are not to be trusted. nt - clarkjohnsen 09:29:51 06/04/07 (7)
    a
    - All switches or just some? And how do you know which ones? nt - KlausR. 09:41:34 06/04/07 (6)
      .
      - how do you know which ones? - unclestu52 21:47:05 06/04/07 (4)
        
        In Reply to: RE: All switches or just some? And how do you know which ones? nt posted by KlausR. on June 04, 2007 at 09:41:34
        
        Hi Klaus:
        
        I remember asking you the mode of your polarity switch. Your reply was that you didn't know.
        
        If you open your unit up, you ought to be able to do a simple trace to the switch. If the traces trigger a relay which is connected to pins 2 and 3 of your XLR outputs, you got a good polarity switch.
        
        Stu
        
        RE: how do you know which ones? - KlausR. 05:01:39 06/05/07 (3)
        
        In Reply to: RE: how do you know which ones? posted by unclestu52 on June 04, 2007 at 21:47:05
        
        I asked the designer and here is what is used to invert polarity(see link).
        
        Klaus
        Polarity inverter (Open in New Window)
        
        RE: how do you know which ones? - unclestu52 16:51:59 06/05/07 (2)
        
        In Reply to: RE: how do you know which ones? posted by KlausR. on June 05, 2007 at 05:01:39
        
        It'll take me a while, as I can read French, but not German. The block diagram is of no use as it doesn't seem to identify the polarity switch location or waht is being switched.
        
        Stu
        
        RE: how do you know which ones? - KlausR. 00:42:12 06/06/07 (1)
        
        In Reply to: RE: how do you know which ones? posted by unclestu52 on June 05, 2007 at 16:51:59
        
        It's basically a circuit that converts non-balanced to balanced. In the 3rd paragraph it says that it can also be used in the non-balanced mode for the purpose of e.g. phase inversion.
        
        Klaus
        
        RE: how do you know which ones? - unclestu52 03:05:43 06/06/07 (0)
        
        In Reply to: RE: how do you know which ones? posted by KlausR. on June 06, 2007 at 00:42:12
        
        In the block diagram, the input IC is shown as a voltage amp feeding what I assume is the volume control. From there, the signal is fed to another IC developing a +/- signal, which is then fed to another op amp per leg and then to the output. If the unit simply switches the +/- outputs of the second op amp, the switch will be OK. If it also works by switching the utputs to pin 2 and 3, it'll be OK,too. If it bypasses the output IC's, then there are electrical differences and this may null a proper polarity comparison.
        
        Sorry, I am an old man and my eyes are not what they used to be, so I can't really read the numbers off the IC's and other components. The block diagram shows no polarity switch location and indeed the function of jumper 4, 2, and 1 are not located either. I see no relays on the board, so I am assuming polarity switching is accomplished by switching the jumpers.
        Using the circuit in a non balanced mode doesn't quite make sense since the polarity is referenced to ground and can not really be inverted (the first IC). Once the signal goes through the volume pot and is outputted from the second op amp it is technically in a balanced mode.
        
        Of course I could be dead wrong, as I can't read the German. Reminds me of driving through Germany and trying to make sense of some of the road signs. Things are just whizzing by here.
        
        Stu
      - I listen. nt - clarkjohnsen 09:57:01 06/04/07 (0)
        
        In Reply to: RE: All switches or just some? And how do you know which ones? nt posted by KlausR. on June 04, 2007 at 09:41:34
        
        s
RE: some thoughts on polarity - truthseekerprime 15:23:19 06/03/07 (1)
Now for the issue of the audibility of polarity inversion in music.

First, I have been unable to find any peer-reviewed published evidence that demonstrates audibility for musical selections. Instead, controlled tests done with very high-fidelity and low-distortion (usually ESL type) loudspeakers, playing mono tracks in acoustically isolated environments, and using musical selections chosen by the researchers to have the greatest asymmetry in the waveforms (so as to make polarity as audible as possible) have failed to find audibility except for a very few special cases. Those cases were essentially individual tones played by a single acoustic intrument. If other evidence exists, please comment.

There is some anecdotal evidence that polarity can be audible in music, particularly when LPs are used as the source. One interesting possibility is that polarity is or can be audible on such systems because they themselves add a significant amount of asymmetric distortion. LPs in particular are susceptible to that - the needle moving up is not necessarily equivalent to the needle moving down, and so asymmetric waveforms can be made even more so by added distortion. Therefore the first task, if audibility can be demonstrated with music in some audio system, is to determine whether the effect comes from distortion in the playback chain, or whether it was present in the original recording. There are a number of tests that could be done to check this.

If audibility of polarity inversion can be demonstrated, the next question is whether there is any such thing as absolute polarity - in other words, is there a polarity choice which is in some sense higher fidelity or superior to the other. For the case of test tones, where polarity is demonstrably audible, there is clearly no such choice.

Now consider the case of a single acoustic source recorded with a single microphone. In that case one could control the polarity throughout recording and mastering and playback, so as to ensure that a compression wave generated by the original instrument corresponds to a compression wave generated by the speakers in the listening room. Presumably this could be regarded as the "correct" setting for polarity.

However there are two major problems that arise the moment we consider a more realistic situation. Suppose there are two mics separated by some distance which an engineer will later mix down into one track. Suppose also there is more than one source of sound (either because there are two instruments/voices, or because of reflected sound in the studio). In that case it is simply impossible to make a polarity choice that corresponds to the original polarity. The reason is that because the two mics are separated, they will be out of phase on nearly all components of the signal (recall that audio frequency sound waves have a wavelength which is of order a few inches), and will not receive the leading impulse of sound at the same time. With more than one sound source there is no way to time-align the arrival of both sources. Recall also that the phase or polarity of a sound can be inverted upon reflection off a surface, or in the case of a dipole radiator by simply moving 180 degrees around to the other side of the instrument. Therefore there is no way to time-align or phase align the two mic tracks in such a way that the mixed track preserves the original polarity in any sense, nor do audio engineers even consider doing so (as far as I know).

The second problem is with stereo - even if only two mics are used, one for each stereo track, unless the speakers are positioned exactly as the mics were in the studio, the signal that arrives at the listener's ears will suffer from phase distortions (although in this case it might still be possible to preserve at least some of the polarity information).

The only way I can see to make a recording that preserves polarity or phase is to make a binaural recording (two mics about as far apart as your ears, one for each track) played back through headphones. Maybe some sort of standard for dual-mic recording could be developed that would make it possible to arrange something like that for stereo playback through speakers, but so far as I know there are no such recordings in existence now.

Therefore I reach the tentative conclusion that polarity is not an issue to be concerened with for musical playback using extant recordings. I don't attempt to impose this conclusion on anyone else - if you believe polarity makes a difference in your system, that's absolutely fine with me. However I welcome constructive comments, criticism, and suggestions from anyone, but anecdotal evidence or flames (polarity is obviously audible, you must be deaf, blah blah) will be ignored.
- RE: some thoughts on polarity - TomLarson 17:02:52 06/03/07 (0)
  I imagine straightforward statements by posters who say they can hear polarity effects on a wide range of current recordigns, both cd's and lp's won't do anything for you, huh? Because there are lots of posts here which say just that. So I don't get the point of your posts.
Audibility will depend almost entirely on the speakers used. - Dave Pogue 14:53:18 06/03/07 (19)
"Low distortion" per se will have little to do with it, IMHO.
- can you clarify? - truthseekerprime 15:26:21 06/03/07 (18)
  Do you mean that some speakers will react asymmetrically, thus producing a distorted copy of the signal for which polarity is easier to hear, and for those speakers it's audible? Or do you mean that most speakers are not high fidelity enough and hide the effect?
  
  In my experiments with test tones I haven't found the speakers to be a major issue - I can hear the effect (with some difficulty) even on my laptop's speakers, but it's easiest through headphones.
  - RE: can you clarify? - Dave Pogue 16:22:34 06/03/07 (17)
    We're going over old ground here. Most speakers will not reveal audible polarity diferences largely because (1) they are not polarity coherent and/or (2) they have complex crossovers. For instance, to expect ANY speaker that has its midrange driver wired out of phase with its other driver(s) to reveal polarity differences -- on music -- is silly. The audibility of polarity via test tones is not the issue and, AFAIK, never has been.
    - There is a lot of misinformation about difference between polarity and phase. - Presto 11:47:13 06/04/07 (4)
      So... we're saying that a "polarity coherent" speaker has drivers that are corrected in the same polarity? So what?
      
      A 4th order linkwitz riley (LR) has all drivers connected with the "same electrical polarity" (which is POST crossover). But it has far greater group delay (which is NON constant) than a 2nd order LR which has the tweeter polarity inverted. This is due to a 180 degree phase shift imparted by the 2nd order CROSSOVER at Fc (crossover point). The further away from Fc we go, the less a "polarity flip" is the correct answer.
      
      The 4th order seems better because the tweeter is not flipped ("polarity coherent" as they are referred to in this thread"). But this is only because the crossover imparts a 360 degree shift. Although this seems 'more correct', the crossover + driver phase shift will result in greater parallax error due to greater group delay than the 2nd order. (greater rate of change of phase w.r.t. frequency).
      
      3-way 3rd order butterworth is a neat example. LF section imparts 270 degree LAG, HF section imparts 270 degree lead. The net resultant difference between HF and LF filters is 180 degree - again, calling for a driver inversion, this time the midrange.
      
      The only crossover/driver combination that is allegedly "phase coherent" AND "polarity coherent" (coherent is a poor choice of words for polarity really) is the 1st order acoustic which imparts a 90 degree shift between LF and HF sections. This phase shift is constant w.r.t. frequency - thus the system would have a constant group delay, and thus, perfect step response (aka zero parallax error).
      
      The trouble with 1st order "acoustic" crossovers is how we manage to deal with the 12db/octave (2nd order) roll-offs of woofers (as band bass devices) and tweeters (as high pass devices). Very often 1st order speakers have a 1st order ELECTRIC crossover - not a 1st order acoustic. Due to the shallow slopes of the 1st order, the rolloff of usually all drivers in the system are going to overlap with the crossover regions, resulting in acoustic slopes as high as 3rd order.
      
      I find it very curious (downright suspicious actually) as to why the "perfect polarity brigade" will always mention that speakers need to be "phase coherent" or "polarity correct" but will rarely (if ever) volunteey WHAT SPEAKERS SPECIFICALLY they are talking about. It's always "you need the right speakers" but never "you need THESE speakers".
      
      Myself, I would like to see a consortium (of some kind) of speakers that the perfect polarity people would deem to be adequate for this task. Or at least tell us what speakers THEY have that enables them to hear the polarity effects they are describing.
      
      Since speakers are so critical for this to work, I've always wondered why they stop at "you need the CORRECT speakers" but never go on to say which speakers meet their criterion.
      
      Saying all that, this does not mean I am opposed to the idea (concept if you will) that changing the polarity of an asymmetric waveform would have an audible effect. The "story" that our ears act as rectifiers, or simply respond differently to compressions than rarefractions, is a good one. This would require much more understanding of the relationship between the mechanics of the human hearing system, the brain, and how we perceive sound. It's not enough to look at speaker wiring and stop there IMHO.
      
      Three things are for certain:
      
      1) 1st order electric does not guarantee 1st order acoustic.
      2) Polarity of drivers is meaningless without examining crossover toplogy.
      3) Uniform polarity is not an indicator for group delay and phase shifts.
      
      Until we have established a list of speakers that work for demonstrating the effects of polarity, I think "who hears what" becomes a rather mute point... does it not? Sure, basic "types" of speakers have been mentioned or recommended - but what DEFINES and differentiates these "types" of loudspeakers is still largely obfuscated by misapplication of terminology - people having different definitions for the same words.
      
      Cheers,
      Presto
      - A very short list - unclestu52 21:24:54 06/04/07 (0)
        
        In Reply to: RE: There is a lot of misinformation about difference between polarity and phase. posted by Presto on June 04, 2007 at 11:47:13
        
        Ryan Acoustic speakers (not all are perfect, but most models are very good)
        
        Vandersteen Audio
        
        Original Quad ESl 57's.
        
        Martin Logan full range electrostatic model (Sorry I forgot the name).
        
        Sonance Symphony 622C
        
        There may be others, but these are a few I have actually heard and lived with.
        
        Your point is a good one, as too many do not realize the range of phase exhibited by most speaker designs. In addition I find that designs with front mounted ports or radiators also throw out an audible signal which is out of polarity to the driven speaker.
        
        Stu
      - RE: There is a lot of misinformation about difference between polarity and phase. - truthseekerprime 12:26:57 06/04/07 (0)
        
        In Reply to: RE: There is a lot of misinformation about difference between polarity and phase. posted by Presto on June 04, 2007 at 11:47:13
        
        My understanding is that the Gallos don't use an electronic crossover at all, apart from a low-pass filter at 125 Hz for the woofer. This is possible presumably because Gallo was able to choose the drivers so that their mechanical characteristics suffice to keep the frequency response level.
        
        This does NOT mean the speakers are phase or time coherent - driven damped mechanical oscillators have phase delays just like their electrical counterparts. Exactly how great those delays are in this case I'm not sure, but it seems like they must be pretty large (otherwise the frequency response would be very far from flat and you'd need a crossover). Maybe there's a review somewhere that measured the phase response?
      - RE: There is a lot of misinformation about difference between polarity and phase. - Dave Pogue 12:06:46 06/04/07 (1)
        
        In Reply to: RE: There is a lot of misinformation about difference between polarity and phase. posted by Presto on June 04, 2007 at 11:47:13
        
        I assume you mean "connected" rather than "corrected" in the first paragraph and didn't read my post indicating that I use Gallo Reference 3 speakers.
        
        Beyond that, as a borderline technical illiterate who wouldn't even have ventured into this topic except for my "extremely polarity sensitive" speakers (again, quoting a Gallo tech guy), I am not equipped to comment. I definitely would like to see a list of speakers that demonstrate the effect unequivocably, as mine do.
        
        Thanks to all for the "real world" examples. - Presto 11:19:42 06/05/07 (0)
        
        In Reply to: RE: There is a lot of misinformation about difference between polarity and phase. posted by Dave Pogue on June 04, 2007 at 12:06:46
        
        You see, gents....
        
        As of late I've been spending a lot of time pondering (and trying to learn about) the potential effects of phase anomalies (and ways to circumvent these problems.)
        
        An interesting questions is: IF phase coherence is necessary for revealing the effect of inverted polarity, then what ELSE are non-phase-coherent speakers hiding??
        
        HMMMMMMMMMMM...
        
        Happy news if you use digital sources... by using a technique called "forward-reverse processing", it's now possible to use algorithms to literally remove the phase errors introduced by loudspeaker drivers and crossovers.
        
        With passive components, we're limited to drivers that can behave with a 1st order acoustic design which is a very very short list indeed. With digital phase correction, even steep slope crossover algorithms (as required for ribbons for example) could be used.
        
        The trick is to put together a system that performs the DSP in a manner that is transparent enough for even the most discerning digital-phile.
        
        Convinvcing vinylholics to digitize their beloved recordings to apply digital phase correction? I'm not going to approach the lynch-mob with THAT kind of suggestion.... perhaps someone ELSE will volunteer to "share the good news"... :o) As for now, the main selling feature of an "all passive" front end is that it is an ALL PASSIVE front end!! :P
        
        Who knows. Maybe one day, DSP will have the bitdepth, transparency and jitter rejection to be able to not only make polarity identification possible, but also correct the phase errors that make hearing such effects impossible in the first place.
        
        Ah, dare to dream. BACK TO MY LAB!! Bwah ha ha ha ha...
        
        But I do plan to get a record spinner thingamabob here quite soon...just to be able to enjoy digital free music. Music that was never a one OR a zero.
        
        Cheers,
        Presto
        
        Cheers,
        Presto
    - RE: can you clarify? - truthseekerprime 20:52:17 06/03/07 (11)
      Right - I forgot to add crossover phase distortions to my second post on the reasons why this is unlikely to matter for anything most people care about.
      
      But the careful experiments researchers have performed were done with ESL speakers or single driver headphones to avoid this problem. Essentially every possible advantage (except for added distortion) was given to the listeners, and yet they were still unable to hear polarity inversion on music. So if it's there, it's either very very subtle or it's there because of distortion somewhere in the audio chain.
      - Polarity and ESLs - Dave Pogue 04:23:15 06/04/07 (10)
        
        In Reply to: RE: can you clarify? posted by truthseekerprime on June 03, 2007 at 20:52:17
        
        I heard a pair of large ESLs (Sound Lab) just last week and polarity changes were inaudible. In fact, the owner had disabled the polarity switch on his preamp in part because he couldn't tell any difference, suggesting to me at least that there are some ESLs that are not polarity-coherent.
        
        On the other hand, my Gallo Reference 3s are "extremely polarity sensitive," according to a tech rep at Gallo who responded to my rather mystified query. I had never heard polarity changes before getting these speakers, which are polarity-coherent by design and have no crossover at all between mids and highs and a minimal one between woofer and mids.
        
        The published list of record labels in articles in the old Fi and Ultimate Audio magazines are excellent starting points, I find, for determining which records/CDs/tapes are in "normal" and which in "inverted" polarity. Would that it were not so. It's a pain in the neck to switch speaker cables (my only way of doing this).
        
        BTW, as others have pointed out, some discs were made in mixed polarity or with, say, a vocalist recorded in one polarity and the instrumentation in another. I can put the vocalist in the foreground or background on these by switching speaker cables.
        
        Yes, it's subtle, but once you hear it you can't NOT hear it. to my regret.
        
        RE: Polarity and ESLs - truthseekerprime 06:51:14 06/04/07 (9)
        
        In Reply to: RE: Polarity and ESLs posted by Dave Pogue on June 04, 2007 at 04:23:15
        
        Well, I was planning on auditioning the Gallos soon, so maybe when I do I'll give it a shot. Any suggestions on a particular CD you find the effect especially obvious on?
        
        The Gallos do have a crossover, it's just low order (which means smaller - but non-zero and still significant - phase shift). Another thing people sometimes forget is that any mechanical driver will by itself induce a frequency-dependent phase shift (look up driven damped harmonic oscillator), even with no crossover. The only way I know to produce truly phase-coherent sounds is to correct for all the phase anomalies with digital signal processing.
        
        In my experience it's almost always easier to hear subtle effects like this with headphones, where these issues are mostly ameliorated, so that's what I've used primarily in my own experiments - and I have not been able to hear the effect of inverting a musical track.
        
        recordings - unclestu52 21:55:12 06/04/07 (0)
        
        In Reply to: RE: Polarity and ESLs posted by truthseekerprime on June 04, 2007 at 06:51:14
        
        Try the following:
        
        Holly Cole trio "Don't Smoke in Bed" The voice and bass are inverted a but the piano is in correct polarity. TAS recommended the Canadian pressings for superior sonics, but the polarities are simply reversed on the Canadian pressing.
        
        If you like vocals, Mary Black's CD's are usually inverted, at least all the ones I heard (some 8 titles or so).
        
        The Michael Crawford album is interesting. His voice is inverted, but in the duets with Barbara Bonney (the only reason I purchased the disc), her voice is inverted to Crawford's. I do believe he uses an Aphex Aural exciter however.
        
        What kind of music do you listen to, BTW?
        
        Stu
        
        Okay, here's the test CD. - Dave Pogue 09:53:45 06/04/07 (4)
        
        In Reply to: RE: Polarity and ESLs posted by truthseekerprime on June 04, 2007 at 06:51:14
        
        Elgar and Bax violin sonatas by Tasmin Little and Martin Roscoe. GMNCO113 (GMN = Global Music Network label). Highly recommended in an old "Listener" magazine. I bought it, thought the violin sound was wiry and astringent and the piano was clanky. Put it aside. Just switched the speaker cables a few minutes ago and ...
        
        voila.
        
        So THAT'S what the reviewer was talking about. Surprised I didn't think of this earlier but, really, I try not to focus on the polarity thing unless stimulated by something like this thread. I've already switched back and forth three times this morning.
        
        But if you can't hear the effects of polarity switching with this disc there's something amiss with your speakers (not polarity coherent) or your system's resolving power or (sorry) your ears.
        
        RE: Okay, here's the test CD. - truthseekerprime 20:19:17 06/04/07 (2)
        
        In Reply to: RE: Okay, here's the test CD. posted by Dave Pogue on June 04, 2007 at 09:53:45
        
        OK - that CD is on its way. Is there any particular track or section of a track I should listen to where it's especially obvious?
        
        I can even try it on the Gallos, as there's a dealer around the corner. But if phase coherence is the isssue, phones win hands down over just about any speaker.
        
        With respect to speaker-listening, - Dave Pogue 03:12:18 06/05/07 (0)
        
        In Reply to: RE: Okay, here's the test CD. posted by truthseekerprime on June 04, 2007 at 20:19:17
        
        with the Gallos or any other coherent speakers already listed, you have to learn to listen for the effects and they may not be immediately obvious, eliciting an "Is THAT all it is?" reaction. If it WERE really obvious, speaker designers wouldn't routinely wire their speakers in mixed polarity with complex crossovers and every linestage/preamp would have a polarity switch.
        
        But then again, you have to ask yourself why DO some preamps and CD players have such a switch if it doesn't do anything audible?
        
        Any track will do. - Dave Pogue 02:56:39 06/05/07 (0)
        
        In Reply to: RE: Okay, here's the test CD. posted by truthseekerprime on June 04, 2007 at 20:19:17
        
        Just start at the beginning. Also, if you have any of the Mercury Living Presence classicals (CD or LP), I find all of them so far to be "inverted." Listened last night to the Bloch Concerto Grossi (CD/LP) and the CD of Howard Hanson conducting Barber, Piston, Griffes, et. al. (#434 307-2) With the Mercurys, I hear distinctly less wiriness, brightness, and edge with the speaker cables connected red to black (+/-) at both speakers.
        
        OK, I'll try to get hold of that. - truthseekerprime 10:24:05 06/04/07 (0)
        
        In Reply to: RE: Okay, here's the test CD. posted by Dave Pogue on June 04, 2007 at 09:53:45
        
        x
        
        This just in. - Dave Pogue 08:13:38 06/04/07 (0)
        
        In Reply to: RE: Polarity and ESLs posted by truthseekerprime on June 04, 2007 at 06:51:14
        
        Was listening to a Doris Day/Andre Previn Trio CD called "Duet" originally recorded a LONG time ago and became increasingly aware that she sounded just a bit ... muffled. Switched speaker cables and she opened up nicely. This is NOT fun. Can't explain it by label -- this one was originally on Columbia LP, now on Sony Special Products CD. Again, it's to some extent a learned thing -- I wouldn't even have noticed it a while ago and I'm sure the difference is totally inaudible via most speakers.
        
        RE: Polarity and ESLs - Dave Pogue 07:29:17 06/04/07 (1)
        
        In Reply to: RE: Polarity and ESLs posted by truthseekerprime on June 04, 2007 at 06:51:14
        
        How do you do the inversion with headphones if you don't have a polarity switch on your preamp/linestage? or maybe you do.
        
        For me, the most audible polarity changes are on LPs and reel-to-reel tape. If you're sure you have it right in the first place (i.e., "normal" or "non-inverted"), then try something on Deutsche Gramophon or London/Decca or Mercury Living Presence, which should sound slightly "off" until (in my case) switching speaker cables.
        
        As noted, it can be very subtle until you lock on to a veiled or duller sound that becomes more open and clear when you switch. Sometimes it's the other way around -- sounding too bright/edgy when played back in the wrong polarity. To demo this effect to others, I have a r-r tape on DG of Martha Argerich playing Prokofief and Ravel piano concertos that I considered virtually unlistenable before playing it in "inverted" polarity. Still no world-beater, sonically, but an easily audible improvement.
        
        I've often wondered whether recordings remain (or are kept) in the same polarity when transferred from LP to CD and SACD because the effect can be so much more pronounced on LP and tape, in my experience.
        
        RE: Polarity and ESLs - truthseekerprime 10:26:24 06/04/07 (0)
        
        In Reply to: RE: Polarity and ESLs posted by Dave Pogue on June 04, 2007 at 07:29:17
        
        I don't currently have a pre with a polarity switch. For the experiments I'm doing now, I take a WAV file ripped from a CD, invert it using audio software, and then listen using a squeezebox 3.

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