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"Different players have different features and it is with these that I find sonic differences can arise.
For example, if one were to adjust the playback level or apply on-the-fly sample rate conversion or any other process, sonic differences in the "engines" would manifest themselves.
I've said before that I have taken files I ripped using iTunes (all my CDs are ripped to .aif format with iTunes' error correction turned on) and compared them directly with the masters used to create the CDs from which the files were ripped. What I found was the files, in every case, were identical.
I could place the ripped file and a master file into my mastering software, synchronize them perfectly, invert the polarity of one file, then listen to the results of the two combined files. (This is called a null test.) the results contain only what is different between the files. They can then be amplified to see (and hear) what is different between the files. If the files are identical (perfectly identical), the result would be a null, i.e., the result would contain nothing at all.
That is exactly what I've gotten with all the files I've ripped into iTunes and compared against the masters used to create the CDs from which the files were ripped. In other words, the rip is the equivalent of the master. As a result, this leads me to think any departure is by definition, a departure from the master - regardless of whether anyone *likes* it more.
Yet, folks tell me they hear differences in the applications with just straight playback. I have a number of different "server" apps on my machine and though there have been times I *thought* I heard a difference, further testing has shown me that I can't reliably do so and the apps are in effect, sonically equal - at least to my ears, so far.
I've also used my gear to capture the output from the different apps playing the same file, from a point just ahead of the DAC chip in my converters, then performed null tests on each of the files against the master as well as against each other. In every case, a null was achieved.
Do I think sonic differences are impossible? No. I just haven't heard any yet and have not been able to conceive of a mechanism by which sonic differences might arise. Of course, sonic differences don't require my being able to conceive of a mechanism for their existence. ;-}
So, I keep listening but so far, the only differences I've experienced are not sonic. (I do not apply processing of any kind when listening and I adjust level in the analog domain.) Where some other apps *do* have an "advantage" is when playing files of different sample rates. With iTunes, to hear a file at its native rate (my preferred way to listen), I must quit the program, open Audio/MIDI Setup and adjust the sample rate to that of the next file I wish to play, then re-launch iTunes to play the file. Some of the other programs will switch sample rates automatically to follow the native rate of the file being played.
On a related note, I have heard differences between different CDs created from the same master, i.e., containing identical *data*. However, it should be remembered that when playing a CD, there are a lot of processes that occur just to get to the data. (There are no "ones and zeros" on a CD but instead, nine different length "pits" from which the data must be decoded.) When these CDs are ripped to the computer's hard drive, all the sonic differences disappear. I've never heard a CD, even among the very best pressings, that I've found indistinguishable from the master used to create it. The story changes completely when the CD is ripped to the computer. On the computer, it effectively *is* the master.
Best regards,
Barry
Soundkeeper Recordings
Barry Diament Audio "
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