Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: CD's weak error correction - artefacts on bought CD's? (Read 13232 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

CD's weak error correction - artefacts on bought CD's?

Reply #25 –
If you mean, what is my source, the particular one for the quotes is Ken Pohlmann's Principles of Digital Audio. He is writing about what is designed into the specifications, the mathematics of how it actually works, not about his personal experiences with audio. Certainly, if there are defects in the media or drive beyond design tolerances, more read errors are likely.

I've only been writing audio CD-R since early 2004, that is the limit of my personal experience. I haven't tested any of those early CDs lately but I've listened to some. It isn't possible to say, based on simple listening that there aren't some subtle, or not so subtle, differences in the music, but it is possible to be pretty darn sure there is no serious deterioration because there would definitely be no question: those won't sound like the music at all. As far as what they do sound like, they sound like they used to sound when new, at least to the extent that I can't notice anything different.

There is this theory of evolution based on mutations from random alterations to genes. It may be true, but the overwhelming majority of random alterations are noise; they are non-function and usually deadly. It is easy to understand, and demonstrate, that random changes to audio data is analogous. Can you demonstrate, or provide any found examples of, random changes that just make subtle musical changes?

If the uncorrectable error is in the least most significant bits, it will probably be a tiny noise, and not likely audible. If it is in the most significant bits it will almost certainly have a big, and very obvious impact. It will not sound good, and it isn't likely to pass as a different version of the song, it will be obvious noise -- crack, snap, pop.

Maybe somewhere in between those two extremes there might be noise that isn't totally inaudible but is subtle enough not to be an obviously. I suppose it could happen but could it happen often enough to actually make changes to the music that you might think were part of the music unless you did a close comparison to the original? And not be accompanied by a similar number of higher order bit errors that would be very obvious as faults (these re random errors, remember, not some carefully planned sabotage)? Seems unlikely to me.

CD's weak error correction - artefacts on bought CD's?

Reply #26 –
Quote from: jamie_P84 on
I certainly have numerous poor-sounding CD's in my own collection, to which the above could apply.


If a CD is mastered from a source that has hard-encoded errors, of course the new one will have the same errors (unless there has been intervention specifically to correct them).
If suboptimal ripping was employed, then new errors could be introduced.

How this would explain the existence of  'numerous poor sounding CDs'  is my question to YOU.

What constitutes 'poor sounding'?  Pops/tics?  Or something else?  Please describe.  And maybe list the names of some of these 'numerous' poor sounding CDs, and describe what makes them sound poorly to you.  Then we can tell you whether the 'poor sound' is likely to have come from the mechanisms you posit.

CD's weak error correction - artefacts on bought CD's?

Reply #27 –
Quote from: krabapple on
What constitutes 'poor sounding'?  Pops/tics?  Or something else?  Please describe.  And maybe list the names of some of these 'numerous' poor sounding CDs, and describe what makes them sound poorly to you.

No maybe, otherwise we might again encounter this type of unsubstantiated nonsense which landed in the recycle bin:
Quote from: jamie_P84 on
For comparison purposes, I recently made a number of insecure CD rips with AudioGrabber, then cleaned the discs (they were in average condition, with some fingerprints etc.) and re-ripped them accurately with EAC. There were no skips, yet on my better-sounding CD's, the improvement in quality was very noticible. Subtracting the AudioGrabber copies from the EAC ones in a WAV editor (after manually correcting the offsets) confirmed that there were indeed differences between them.

In fact, any descriptions must include samples to be compliant with both TOS #8 and TOS #9.
 

CD's weak error correction - artefacts on bought CD's?

Reply #28 –
Quote from: greynol on
Quote from: jamie_P84 on
Clearly no-one here has professional mastering experience, so I've wasted my time.
Actually there are people here with such experience

...and if people believe that, they'll believe anything.
I expect one of your fellow inmates (or ten) will pop up and agree with you, or claim that they're such a person - still won't make it true, though.