[Russell Dawkins]

Lets think about this.  Each instrument or vocalist sends out a sound wave of some random phase angle which you (or the microphone) receives. Your distance from the performance affects where on the wave form the signals from the various performers shows up at you.

But it doesn't affect whether the pressure is initially positive going or negative going. The staunchest proponents of correct polarity  believe that the polarity of the asymmetry of an asymmetrical waveform is important. In fact that is the only reason for concern with "absolute polarity".

Move a few inches and the "polarity" is changed. Add to that the random scramble all the recording devices do.

To my knowledge modern recording devices do not "randomly scramble" polarity!

I doubt very much that there is such a thing as "absolute polarity" in the playback system.  The best we can do in designing playback equipment is to not screw up the recorded polarity. That scramble of wave forms on the recording contain the "where" information about the performance (and more of course).  We want you to hear what the microphones did, and not screw up phase angles and information in your playback system.

Confused? Well me too somewhat.

Frank Van Alstine

In the worst period of large acoustic event recordings (big band, choir, orchestra) which was roughly from the widespread introduction of large mixing boards in around 1962 to maybe 5 or 10 years ago, the notion of recording with mainly a stereo mic array carefully positioned out front and minimal use of spot mics was somewhat abandoned in favor of the control afforded by many spot mics. The main mics became placed way back and became the "room" mics. This is a generalization, of course, as each engineer had his/her own approach. Nevertheless, in the 60s and 70s there was a trend to more use of spot mics. This plays havoc with the sound.

Imagine, if you will the effect of a certain instrument between two, three or four spot mics being represented in each of them at differing levels with different arrival times. This in fact was (is) going on whenever spot mics are used and their output combined with a main mic pair.

All that can be done to alleviate the effect is what I do - get the best possible balance within the ensemble and between the ensemble and the room on the main stereo pair of mics, then use an absolute minimum of spots, and delay each spot by an amount appropriate to the spot's distance from the main, so that it's contribution to the mix will be time-aligned.

So... trying to judge whether absolute polarity is worth paying attention to requires as a starting point a recording made preferably with a single stereo pair of mics and moreover preferably not a spaced pair but a coincident pair, as in Blumlein. This ensures that at least the source is reasonably phase-coherent.

Some would say the speakers need to be of simple design, too, like those using broadband drivers without crossovers to the mids or at least very simple crossovers.

[daj]

As far as I know, I have not yet heard your recordings, Russell, and would be excited to do so. If it would not seem too commercial, would you mention who issues your work and where it can be bought?

[Daygloworange]

But it doesn't affect whether the pressure is initially positive going or negative going. The staunchest proponents of correct polarity  believe that the polarity of the asymmetry of an asymmetrical waveform is important. In fact that is the only reason for concern with "absolute polarity".

Russell,

I'm not sure I understand that fully. Could you elaborate on that in more layman's terms?

Yes, there are a lot of issues combining signals from spot miking and distance miking. It sometimes takes a lot of trial and error. But you can use it to your advantage sometimes and achieve some very favourable (subjective) results.

I prefer distance miking, ( XY and spaced pair)as I find that it sounds more like the instrument, but then you often have to compensate for the lack of proximity effect,and of course use more gain, which introduces more noise floor. Then you have compatibility issues track to track (when mixing and blending)with the room ambiences. It's never going to be perfect. There is always compromise, in one form or another.

Cheers

[Double Ugly]

As far as I know, I have not yet heard your recordings, Russell, and would be excited to do so. If it would not seem too commercial, would you mention who issues your work and where it can be bought?

I'm not Russell, but you may want to try Point No Point by Paul Cantelon.  Wonderful, easy listening solo piano.  One of my wife's favorites.

Russell also has a stunning orchestral recording of the Ukrainian Radio and Television Orchestra performing Romeo And Juliet, Suite No. 2, Op 64ter.  It was quite the rage around here a while back.  I suggest you purchase a copy if you appreciate well-recorded orchestral pieces.

[daj]

As far as I know, I have not yet heard your recordings, Russell, and would be excited to do so. If it would not seem too commercial, would you mention who issues your work and where it can be bought?

I'm not Russell, but you may want to try Point No Point by Paul Cantelon.  Wonderful, easy listening solo piano.  One of my wife's favorites.

Russell also has a stunning orchestral recording of the Ukrainian Radio and Television Orchestra performing Romeo And Juliet, Suite No. 2, Op 64ter.  It was quite the rage around here a while back.  I suggest you purchase a copy if you appreciate well-recorded orchestral pieces.

Thanks, Double.

[Doublej]

Has anyone read Clark Johnsen's book, The Wood Effect: Unaccounted Contributor to Error and Confusion in Acoustics and Audio on the subject?

[peakrchau]

Has anyone read Clark Johnsen's book, The Wood Effect: Unaccounted Contributor to Error and Confusion in Acoustics and Audio on the subject?

No, but you can read about the interesting shouting matches on this issue by Clark Johnsen with HP(TAS), Peter Aczel(Audio Critic), and RH(stereophile) that has led to some of the ill-will between these print magazines in the Letters to the Editor section of Issue 18 from 1992...(1.5MB PDF file/67 pages)...worth the download time for a few belly laughs and  parallels to this thread.

PeAK

[daj]

Has anyone read Clark Johnsen's book, The Wood Effect: Unaccounted Contributor to Error and Confusion in Acoustics and Audio on the subject?

No, but you can read about the interesting shouting matches on this issue by Clark Johnsen with HP(TAS), Peter Aczel(Audio Critic), and RH(stereophile) that has led to some of the ill-will between these print magazines in the Letters to the Editor section of Issue 18 from 1992...(1.5MB PDF file/67 pages)...worth the download time for a few belly laughs and  parallels to this thread.

PeAK

Priceless. Dr. Corey's response, in particular. Man, I see this has been going on for a long time, but it's fresh to me, because  I pretty much ducked out of audio in the late 1970's to escape the family thing. Since returning a couple of years back in late middle age, I've been having some trouble orienting myself within the remodeled landscape, which as I should not be surprised, seems to have had little immunity to the troubles of our society at large. Anyway, thanks for the link, PeAK. Made my day.

[Russell Dawkins]

As far as I know, I have not yet heard your recordings, Russell, and would be excited to do so. If it would not seem too commercial, would you mention who issues your work and where it can be bought?

I'm not Russell, but you may want to try Point No Point by Paul Cantelon.  Wonderful, easy listening solo piano.  One of my wife's favorites.

Russell also has a stunning orchestral recording of the Ukrainian Radio and Television Orchestra performing Romeo And Juliet, Suite No. 2, Op 64ter.  It was quite the rage around here a while back.  I suggest you purchase a copy if you appreciate well-recorded orchestral pieces.

Thanks for that, Jim.
Here's a link to the main thread about that recording:
http://www.audiocircle.com/index.php?topic=20071.0

As to the link Jim provided to the Paul Cantelon information, please be advised that the sound samples are particularly bad and unrepresentative of the real thing (mono, distorted). In reality, the recorded sound is realistic and recorded, again, in Blumlein with a stereo ribbon microphone (Speiden SF12 on the orchestra, Royer SF12 on the piano).


To clarify, DayGlow, I will give you my interpretation of the absolute polarity factor.

Note that I am not an Engineer but a "recording  engineer" i.e., I don't have an engineering degree. I have a lot of respect for what that capital "E" represents, and when someone wants to credit me on a disc I prefer "recordist", but if they want to say "engineer" I make sure a lower case "e" is used.

The waveforms of single instruments are asymmetric to varying degrees. The trumpet, for example, tends to be more than most. This means the waveform will show unequal distribution of energy above and below the zero line, counter-intuitively (to me!). If the waveform is inverted, then this energy distribtution will be inverted and there are those (like Clark Johnson - I have his book) who say this is audible and inferior.
Presumably, the same applies to the much more complex waveform of an orchestra.

I have always taken it seriously and determined whether each piece of equipment I put my signals through inverts or not, just as a matter of good practice, even though it may transpire that there is, in fact, nothing to it. I don't want to put recordings "out there" that are in inverted polarity and later discover that it does matter.

As to personal experience, my only two encounters with it happened about ten years ago. On a few orchestral recordings (Blumlein) with no spot mics on the orchestra but a couple on the chorus, I began noticing that if I physically wired past a processor I was using a small amount of (an SPL Vitalizer) it always sounded distinctly better than even the hard wire bypass within the device, even allowing for the addition of switch contacts. This was a pro-level German made box used across the country by the CBC as a replacement for their BBEs.
Some investigation revealed that my part of the production run of this box inverted the polarity, whether bypassed or not, so presumably the advantage I was hearing was due to correct vs inverted absolute polarity.

The second instance concerns the D/A converters in a couple of different DAT machines I owned, The Tascam DA 30, a pro recorder, and the semi-pro portable DAP 1, made by Casio, it was said. The popular buzz at the time was that the AD converters of the DA 30 were superior, as they should be for a "pro" device, but the D/As on the DAP-1 were superior, which they sounded to be. That is, the DAP analog outs sounded better.

Then I took a close look at the manual for the DA 30 and discovered that the balanced outs were pin 3 hot, which meant that if you were using pin 2 hot as your convention, it was inverting polarity. Inserting an inverting cable (pin 2 on one end to pin 3 on the other and vise versa; pin 1 to pin 1 of course) re-established the expected pecking order.

[Russell Dawkins]

Here are some pictures of asymmetrical waveforms:

http://www.st-and.demon.co.uk/AudioMisc/asymmetry/asym.html

and a whole slew of other references I don't have time to pursue:

http://tinyurl.com/2735wn

[peakrchau]

I've devised a test for "Absolute Polarity" comparing songs with  their "flipped" data tracks when then are both burned  to CD-R.

"For the record, if i swap the reverse the connections of both speakers, i can hear one condition/polarity sound "better". Some have called this "Absolute Polarity". Some claim that something else has changed, instead, giving rise to this audible difference. For now we will not pursue this 'something else' "

With this new technique, I do not hear the change that is introduced by flipping polarity at the speaker connections. More information at this LINK

PeAK

[beachbum]

i voted yes, on my marsh p2000t preamp there is a note on the back of the preamp, try wiring speakers both ways, the preamp is wired out of phase, the best sound was wiring out of phase, or in phase due to the manufacturer wired the unit out of phase, quite confusing, anyway with black on red much better sound,

[peakrchau]

...the best sound was wiring out of phase... with black on red: much better sound.

What you are hearing is exactly what the original experiments did and hypothesized that this had to be due to the "polarity" because nothing else seems to have changed.

The recent experiments that can perform a "like" experiment changing the polarity, but do so in the "data domain" and surprisingly, the same sort of differences attributed, earlier, to "polarity" do not seem to be audible.

To read some more go to this link pointing to an overlooked mechanism referred to as directionality.


PeAK

[NewBuyer]

To read some more go to this link pointing to an overlooked mechanism referred to as directionality.
PeAK

Very interesting read peakrchau, thanks for including that link. 

So from what I gather in this thread, it seems that every link in the chain (from mic to driver) can contribute not only absolute phase polarity issues that may be frequency-dependent, but also cumulative phase-delay issues that may also be frequency-dependent.

Meaning that by the time you have listened to the recording on your own system, no matter how carefully you have tried to consider all of these variables when assembling your system, you really cannot have any idea if what you are hearing is what the recording actually sounded like at the time of recording.

Now I am wondering, do different individual listening room geometries contribute to any of these relative phase-shifts as well, by the time the sound meets the eardrum? What about small changes in speaker position or even orientation (on any of the 3 axes of rotation)? Or the frequency-dependent time-smear effect that I understand the filters in an oversampling DAC will contribute?

Perhaps tube gear introduces enough euphonic distortion to fool the brain into not noticing (as much) all these mangled phase distortions.

Or who knows, maybe it is pointless to even worry about all this stuff. I state this speculation from the standpoint of a learning person here, not trying to conclude anything or argue for a specific position.