CD Tweeks...Improve Ripped SQ?

Steve (Audioengr), I'm not sure that we're interpreting the question the same way. My interpretation is that what is being asked is if playing a computer file from a computer-based source will sound any different depending on whether the physical CD that was ripped to create that file had previously been treated in one or more of the ways listed in the OP, or had not been treated. Assuming bit perfect ripping, of course.

Although I certainly agree with everything you have said in your two posts above, effects that occur when CDs are being listened to don't relate to the question as I interpreted it.

Regards,
-- Al

08-08-13: Mapman
The D/A process (which requires very accurate and precise timing to be done properly) is where pretty much all of the variability comes into play regarding resulting sound quality.

I second Mapman's comment.

Pretty much everything I have read on the subject that I consider to be credible suggests that a CD that is in good physical condition, when played back in real time by a CD player or transport, will have very few if any read errors that are not corrected bit perfectly by the player. My belief, although based on technical understanding rather than experimentation, is that the main reason some CD treatments will improve the sound quality of a CD that is in good physical condition is that the treatments can make it easier for the transport mechanism and its servos to track and read the disc, which in turn will reduce the amount of electrical noise generated by the transport mechanism that may ultimately couple into the D/A converter circuit, where it can affect jitter, and/or that may couple into analog circuitry.

That effect may occur even in the situation where the transport and DAC are in separate components, as many and perhaps nearly all DACs will be sensitive to some degree to jitter that is present in the S/PDIF or AES/EBU datastream they receive.

That specific effect is of course inapplicable to the situation where what is being played back is a computer file that has been created by ripping a CD. So provided that you rip with software that assures bit perfect accuracy, I can't envision any means by which treating the CD prior to ripping would make any difference.

Regards,
-- Al

Jim, my compliments on the thoroughness with which you established that the copy of the untreated CD and the copy of the treated CD sound different. I don't doubt that conclusion.

I'm not particularly familiar with how CD recorders/duplicators are designed, so I won't speculate on a possible explanation. But intuitively I don't find it especially surprising that on-the-fly duplication of a treated vs. untreated CD would result in different sounding copies.

However, I don't see those findings as being relevant to the situation the OP was asking about, in which what is being played is a computer file. The computer files that would be compared having in turn been produced by ripping a treated and untreated CD using software that assures both files have bit perfect accuracy.

Best regards,
-- Al

FWIW, I can only think of one means by which the sonics resulting from playback of two computer files located on the same drive could differ, when the bits comprising their musical content are identical. And assuming that possible extraneous variables such as the warmup state of the components in the system, AC line voltages, etc., are equal when the two files are played back.

That would be if a mechanical hard drive is being used, and one file is very highly fragmented, while the other file is minimally fragmented. The slightly greater amount of electrical noise that is present within the computer when the hard drive is jumping around among different locations while playing the fragmented file conceivably might result in a slight increase in jitter at the point in the system where D/A conversion is performed.

If one of those files had been created from a treated CD and the other from an untreated CD, undoubtedly some audiophiles would conclude that the difference is attributable to treatment vs. non-treatment. But of course in that situation treatment vs. non-treatment would have nothing to do with it.

Best regards,
-- Al

There is a red line between the uber skeptics and the experimentalists.

I would put it that there is a broad spectrum between the uber skeptics and the experimentalists. It is not simply a matter of being at one extreme or the other.

Also, Geoff, although you appear to realize it, let me emphasize that I do not dispute the effects that CD treatments can have on sound quality, when the CD is being played. I do, however, strongly question any claims that treatment before ripping will make any difference when a computer file is being played, assuming that the ripping software assures bit perfect accuracy. They are two completely different situations, and I would not lump them together under the "bits is bits theory."

Regards,
-- Al

09-10-13: Geoffkait
The same reasons why treated CDs sound better than untreated CDs apply to why ripped files produced by treated CDs sound better than ripped files produced by untreated CDs.

I disagree completely. Let's leave it at that, s'il vous plaît.

Regards,
-- Al