Flaws in brand new cds

vbimport

#1

Apologies if this is a stupid question…

I’ve been archiving a lot of music cds lately, and I have noticed during playback that every once in a while, a disc will have a tiny little squeak at a certain, reproducible place. These “flaws” are actually easier to hear when I’m not listening for them – if I focus on the song, they can be hard to pick out, but if I have the music on while I’m doing something else, then tend to jump out on me.

I should also mention that I can hear the effect when listening on a normal cd player, to the cd on a computer with a variety of drives, or to the wav, flac, or ogg output on the computer.

I guess my question is – is this likely to represent an actual flaw in the disc, even if it’s brand new, is it likely to be present in all copies of a given release, or is it worth returning and requesting another copy?


#2

Can the same flaw be heard on the original factory cd?


#3

I have no idea; this is with cds I have purchased, so I’m not sure how to check.

(Have I stumbled across the wrong forum/resource to ask questions like this?)

I actually understand remarkably little about how cds actually work, error correction, etc., so I’m not sure that this question makes any sense, but – given that the drive I am using is producing identical rips of a given track (size and checksum is identical over multiple rips), is there any sort of central repository of checksum information for commercially available cds such that I can verify that the actual disc in my posession is correct?

Thanks for any and all help.


#4

Your fine itp…my question though was simple…if you hear the same glitch on the factory cd…yes its flawed…if not…it’s some other glitch…be it you ripping/recording…or some other quirk…just trying to help ya hoss…:slight_smile:

If your getting valid checksums…the distortion you hear is most likely in your compression…are you ripping and converting to mp3?..if so,try a higher bitrate…192-256…:slight_smile:


#5

Oh, I think I misunderstood your question.

I am hearing the potential glitch when listening to the original cd, the ripped wav, the flac (lossless) encoding, or the ogg (lossy).

I’m using cdparanoia to rip the music, and multiple runs of cdparanoia produce identical results. So I’m confident I’m accurately getting the data off of the disc.

I guess the questions I have are:

  1. is there any way to be sure something is a glitch in the actual physical cd? Without access to another copy of the same disc, I have no easy way to compare. Is there anywhere to go with, say, an md5sum of the ripped track as a wav or similar and compare with a known good value?

  2. is an actual flaw in an audio disc likely? (Say, 2 of the last 10 discs I have purchased.) Such a high error rate seems odd to me, given the needs of, say, a cd-rom for perfect reproduction, but I have no idea what kind of error correction or checksumming is inherent to an audio cd.


#6

Correct me if I am wrong.[ul]
If you are saying that you can here these glitches on both the original and the copy then it is the original at fault.

If you are saying that this only happens on the copied CD or in the ripped tracks be it mp3/ogg/wav then its the ripping software or hardware at fault.

If you are saying that the original CD produces these glitches on your PC whilst playing from the CD but does not produce them on your home CD player then its the CDrom at fault or software.

To my knowledge there is no database for what you are looking for as music CD’s have no form of error correction so one drive will copy a music track slightly differently to another drive so a MD5 checksum would be useless (but I may be wrong but I have never heard of such a site).

Try finding a good music store and buy an original CD that you already own and try to copy it and see if it produces the same problem then this would help to clarify the problem and then go back to the store and say your an idiot but you already own this CD can you exchange it for something else or for a refund.
[/ul]Hope this helps and let us know how you get on.
Also try using EAC to rip a CD track and see if that still produces the same problem.


#7

I agree with JWB…you need to determine the source of the flaw. If I read your posts correctly, you are hearing this flaw on both the factory origingal, as well as your rips.

JWB makes a good point that you need to identify if the cd is bad or if your drive mechanics may be failing. I agree with you that 2 of the last 10 discs is indeed a high error rate.

If the same cd, played in 2 different drive ( 1 your pc, 2 standalone ) I’d say cd. If it plays fine in 1 drive, and glitches on the pc…it’s your pc’s drive.

Some years ago, I had a Lite-on cd-rom…think it was a 4x (remember those days.:slight_smile: ) that was kinda cool, because it was a 4 disc cd changer. I tossed it a couple months later because the shuttle system scuffed up my cd’s so bad the were unplayable in a short time…:slight_smile: