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General Asylum General audio topics that don't fit into specific categories. |
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General Asylum General audio topics that don't fit into specific categories. |
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In Reply to: RE: Cricket Polarity Tester posted by georgelouis on March 15, 2009 at 20:12:20:
Do you have a waveform for the Cricket test signal? A scope trace will do. Or a mathematical formula. Or a list of sample values. If you have one of these, then it is a simple matter to verify that a WAV file contains the correct polarity of the test signal. Any audio editor will do this. Or you can take a hex dump of the file, if you are suspicious of the editor. Then you burn a CD-R from the WAV file. Then you rip the CD-R. You will get the same polarity on the rip. Indeed, you will get the identical samples, possibly shifted a few milliseconds in time if your burner and ripper aren't calibrated. The computer software and hardware are not inverting the polarity on the disk. There has never to my knowledge been a single report of polarity inversion in this gear, because it is operating with bits, not even signed numbers at the level at which it operates. (Incidentally, at this level of bits polarity is important, because CDs and DACs operate with 2's compliment arithmetic and the maximum positive value is +32767 while the maximum negative value is -32768. Thus an unintended polarity inversion in the digital domain would potentially create an arithmetic overflow.)
The reason why CD players invert or don't invert polarity is an accident of their design. For example, two players that have unbalanced outputs might have opposite polarity even though all their digital processing and DAC chips are identical, if one has an output buffer that inverts polarity and the other one doesn't. Another example would be two DACs with balanced output. These could have identical internal circuitry and differ only in the wiring of the pins at the output connector. There is no standard that says what constitutes "correct" polarity for the analog output of a CD player. There is nothing wrong with a player that you say "inverts" polarity or has a "mislabeled" polarity button.
How do you know that a CD is "inverted"? Are you determining this by your listening tests as to what sounds "right" or "good"? If so, how do you know that a sound that you don't like isn't what was intended by the mastering engineer? Indeed, how do you know that his playback wasn't inverted as an accident of his speaker wiring, again because there is no standardization? If your reference is to the microphone output, then how do you reconcile this to recordings made with ribbon microphones (or other mics with figure 8 patterns)? How do you know which side of the microphone was facing the musician? What if a ribbon microphone was placed between two singers? Which artist deserves correct polarity? Assuming you are 100% consistent in your judgment of polarity, what is the basis for your saying that certain recordings are inverted and others are not? Why couldn't a different authority reach the exact opposite conclusion on the same recordings, if for example, his speakers were wired differently? Why would you be 100% right and he 100% wrong? Would it take a holy war to resolve the dispute?
I'm not objecting to the effort you've put in sorting recordings into two bins, nor minimizing the usefulness of these results. I would have no problem if you called the categories "George-A" and "George-B". It is the implication that one set of recordings is correct and the other isn't that I object to.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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Follow Ups
- That all true believers break their eggs at the convenient end. - Tony Lauck 03/16/0908:02:36 03/16/09 (1)
- RE: That all true believers break their eggs at the convenient end. - georgelouis 12:07:13 03/16/09 (0)
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