Noisy CD-Rs (again)

Hello,

I’ve encountered a problem that sounds to me very much like what leatherwood described back in August — http://club.cdfreaks.com/showthread.php?threadid=73876. In his follow-up message he wrote “the first few tracks are near perfect. Then the scratchy sound creeps in and becomes intolerable towards the end of the cdr.”

That is exactly what I’ve encountered on a couple audio CD-Rs I received from a friend. They were burned at 16X on Phillips and AT&T branded (both CMC) media, and made on a BTC 2410M burner using NTI CD Maker. The noise occurs at regular intervals, and sounds very much like a scratched LP that ‘clicks’ with every revolution. The first tracks are clean—the noise begins to become discernable and becomes progressively more prominent toward the end of the disc—the last track or two is completely unlistenable.

Now … here is the detective work I’ve done … (and this is where it begins to get weird!)
Here are the results when these discs are played on various systems.

Played on computer drives:
Lite-On LTR-52327S on my digital audio workstation (Celeron 1.7 ghz, i845E chipset) — Noise is very bad

Lite-On LTC-48161H on my office workstation (Athlon XP 2600+, VIA KT400 chipset) — Noise is very bad
Plextor PX-W1210A on same office workstation — Fairly good - noise is discernable, but subtle

Played on audio components:
Samsung DVD C621 (less than 1 yr old) DVD-CD-mp3 deck on my living room audio system — Noise is not quite as bad as with the Lite-On drives

Kenwood CD-203 (several yrs old) CD deck on my office audio system — Flawless. No discernable noise.

Hold on … we’re not yet done with the weirdness:

Thinking I might be onto something—that perhaps these discs just didn’t like being read at high speeds—I ripped one of them to WAV at 4x using dBpowerAMP’s ‘slow accurate ripping’ setting. Voila! The result was a set of nice clean WAV files—no noise. I then burned these clean WAV files to CD using my Lite-On LTR-52327S drive and Nero 6. The result was a noiseless CD that plays perfectly in ALL my drives and decks.

Here, then, are the questions:

  1. WHERE did this noise come from in the first place?
  2. WHY is it much more evident on my fast drives and DVD deck than on my slower drive and CD deck?

Is this phenomenon somehow related to drive speed and/or sampling rate? Do faster drives and DVD decks sample at a higher rate, picking up flaws that are overlooked by slower drives and CD decks? Or is there some altogether different explanation?

Any and all comments/ideas will be most welcome. THANKS in advance!

I suppose the used CD-R’s are to blame for this, since almost every player you have tested had problems reading the CD properly.

In most cases you’ll have better chances to read an erroneous CD
if you lower the reading speed.
Don’t ask me why. This is very technical (Block Error Rate, the
quality of the HF-signal, tracking, jitter, the used pickup of the CD-player) - all these parameters determine if a given CD can be read correctly).

In the case of my UltraPlex, lower reading speeds can be even worse! :confused:

Probably the noises come from the fact that not all of the read raw data could be corrected.
Stand-alone CD-players try to conceal such errors by guessing the affected samples as last instance.
CD-ROM drives normally don’t do this (at least, if they use DAE for playback).

I recommend to back up the CDs as long as you are able to extract them error-free.

The recording quality (not the resulting audio quality which
should be the same until uncorrectable errors occur) highly depends on the used media in conjuction with the burner’s firmware (which should be kept up-to-date).

Is this phenomenon somehow related to drive speed and/or sampling rate? Do faster drives and DVD decks sample at a higher rate, picking up flaws that are overlooked by slower drives and CD decks?

If you mean the sample rate of your audio material, the answer is no.
It is sampled at 44.100 Hz / 16 Bits.
Faster drives just need less time to read the same amount of data.