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Old 11th February 2012, 02:34 AM   #1
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Default 30 Years of Digital and the 92% Solution

Dear Music-Loving Audiophiles:

Please read the information at: http://www.AbsolutePolarity.com .

George S. Louis, Esq., CEO
Digital Systems & Solutions
Website: www.betterfi.com
Phone: 619-401-9876
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Old 11th February 2012, 03:43 AM   #2
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Perhaps you ought to place your disclaimer ("The ideas expressed on this website are the opinions of the author and therefore their value and truth should be determined by the readers for themselves.") at the TOP of that page.

Anyway who cares about random "mistakes" in absolute phase when the music is phase-random to begin with? I mean random random is still random!

The very first line of that article is nonsensical. It reads: "Reproduced music is in absolute polarity when its compressions and rarefactions are in sync with the compressions and rarefactions of the original performance." So what? If the mics were moved just marginally certain frequencies would be inverted onto the recording anyway. If you move your head a tiny amount during playback of the most "phase-perfect" recording on the most "phase-perfect" music system (even if you wasted your time calibrating it all with a microphone like some of the manufacturers get you to), the polarity is going to invert into your ears at certain frequencies. MUSIC SOURCES ARE PHASE-RANDOM. Even the sound from a single violin is phase random as it reflects off different surfaces of the instrument. Apart from the tiny blip during changeover, I cannot hear so-called 180 degree "absolute phase" (polarity) reversals and the approach of certain highly regarded digital equalisers and crossovers to achieve alleged phase perfection is nothing but marketer's emphasis of the irrelevant. The only place that phase "correctness" is audible is at the crossover frequencies of your speakers. What you hear is the summed amplitude response. If phase is out around the crossover points, the levels will suffer. Even if linear phase digital crossovers are used, so what? The source on the recording is random. A LW 24dB/octave crossover for example can invert polarity in the middle of the midrange band (compared to the input signal). If you press a 180 degrees flip button on your CD player the crossover output is gonna be inverted somewhere else instead.

Even with headphones (no crossovers) you and I will not perceive a polarity reversal on a played music source. Forget triangle waves.

Why should we read your commercially motivated scientifically deficient nonsense? You are selling "CD dampers" and throwing the word "Platinum" about for goodness sakes!

Oh, I forgot: The ideas expressed in this post are the opinions of the author and therefore their value and truth should be determined by the readers for themselves.
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Old 11th February 2012, 04:00 AM   #3
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Default 30 Years of Digital and the 92% Solution

Dear Ian,

You've misunderstood what acoustic polarity is about. No matter where you sit the leading edges of the acoustic wave that your ears pickup as sound has the same polarity. 12db x-overs do inverter polarity by 180 degrees (+90 degrees and -90 degree relative to each other) in the at their x-over frequency, therefore to avoid cancelation at of the highpass and lowpass drivers output at an around the x-over frequency the highpass and lowpass side of the x-over speaker's drivers must be connected in opposite electrical polarities which makes the highpass and lowpass drivers 180 degrees out of phase with each other in the center of their passbands. However, 4th order x-overs put their highpass and lowpass drivers 360 degrees out of phase at the x-over frequency so no reversing of the electrical polarity of the highpass and lowpass drivers is required even though compared to lower order x-overs there's more group delay. Therefore, if possible no x-over or first order x-overs (6db, that are +45 degrees and -45 degrees that adds up to zero degrees) is the only transient perfect x-over.

It seems to me that you haven't read the entire monograph. Many much more technically knowledgeable and astute music-loving audiophiles and audio engineers than I am haven't raised the objections that you have.

Respectfully submitted,

George S. Louis
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Old 11th February 2012, 05:40 AM   #4
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When opening lines seem bogus, I see little requirement to read on. Your last one is a case in point. Thank you. No further interest here.
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Old 11th February 2012, 06:17 AM   #5
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Dear Ian,

I suppose it's too much to ask that you do some homework on what absolute polarity is all about and how crossovers function. You don't have to take my word for the truth of what I state, simply ask any audio engineer or electronic engineer for their opinions, and if they can prove me wrong I'll listen corrected. But none so deaf as those who will not hear and in the land of the deaf the one eared man or woman is king or queen.

Respectfully submitted,

George S. Louis
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Old 11th February 2012, 07:12 AM   #6
benb is offline benb  United States
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It appears you were making a similar argument five years ago when you revived this seven year old thread by making posts #16 and #17:
Audibility of Absolute Phase

As said earlier in that thread, the claim of audibility might or might not be true (or more diplomatically, it might be true for some and not for others), but since it's easy enough to check that polarity is maintained through the whole signal path, it's done as a matter of course "just in case."

Maybe ten years ago there was a claim on rec.audio.pro of polarity audibility with a 20Hz sawtooth wave. A .wav file was generated with a couple seconds of "positive" sawtooth and a couple seconds of "negative" sawtooth. I downloaded and listened, and while I could tell the discontinuity at the point where it changed from one to the other, I couldn't hear the difference.
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Old 11th February 2012, 07:27 AM   #7
godfrey is offline godfrey  South Africa
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Hi George
I have no problem with the idea that absolute phase reversal is audible, but I'm surprised at your finding that it is reversed 80 to 90% if the time. I would have expected that some labels make an effort to get it right these days, and that the rest would be random.

I notice that you came to this conclusion after "determining the polarity of over 3,500 CDs", but I'm curious as to how you did that. Was it purely subjective, as in "this polarity sounds better than that polarity", or were you looking e.g. for telltale known waveform "fingerprints" of certain instruments?

On a related note, there's some interesting examples of asymmetric waveforms here: Asymmetric musical waveforms. Of particular interest is the violin example about 2/3 of the way down the page. I can't help wondering if that was due to an editing accident, or due to the violin actually producing a reversed waveform.
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Old 11th February 2012, 07:53 AM   #8
godfrey is offline godfrey  South Africa
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Quote:
Originally Posted by benb View Post
...old thread...
Audibility of Absolute Phase...
Reading through that, I found this interesting comment:
Quote:
Originally Posted by float View Post
[snip]
The most amazing difference was on a Paco Pena solo guitar piece, where switching polarity actually changed the tonality of the guitar. I could liken it to the difference between strumming up or strumming down. I guess the greatest benefit of getting the absolute phase correct is with instuments with lots of leading edge information and simply mic'd recordings.
That seems to tie up with speculation here about the inverted violin waveform:
Quote:
An interesting possibility is that in one case the note was ‘up bow’ and the other was ‘down bow’ since we may expect the direction of bowing to be significant.
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Old 11th February 2012, 06:32 PM   #9
benb is offline benb  United States
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It's notable that instruments have different tone at different angles and distances (which makes microphone placement so important in a good recording). It would be interesting to do a polar plot of waveform (or characteristics such as asymmetry and crest factor) versus angle of the instrument with respect to the microphone.
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Old 11th February 2012, 06:40 PM   #10
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Dear Music-Loving Audiophiles:

At the link Polarity Think Piece: A Speculation Regarding Perception of Detail | UltraBitPlatinum.com to Polarity Think Piece: A Speculation Regarding Perception of Detail, I describe how I test by listening and more about the audible differences between in and out of absolute polarity. I also describe a totally objective test of the audibility of relative polarity with music samples.

Respectfully submitted

George S. Louis
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