I regularly check my backup copies on CD-R (used for playback in my car etc.) for errors using EAC and comparing with checksums. Today I heard a click in a rip from a CD-R copy of Bob Marley - Greatest hits, but no error was reported in EAC, so I loaded it into CEP to view the waveform. When zooming in I noticed jitter. Here's a screenshot:

graph by CoolEditPro

green: original CD
red: copied CD-R, jitter is clearly visble.

I always thought that this can't happen and I'm not completely sure how this is possible, maybe it's related to burnproof kicking in when the PC was under heavy load during burning - I have no idea... But it seems like there might be some truth in audiphile claims that CD-R sound different sometimes.

Kinda off-topic, but how did you manage to make CoolEdit show samples instead of time indices on the x axis?

This is my question too. As each sample represents a defined point in time how can the time base be distored in a ripped file? I would think you could only see jitter at the raw analog RF laser signal or the D/A clock of a soundcard/CD player.

Urgh! I didn't noticed this post until resurrected by GenjuroXL (BTW, just right click on the "Time display" in CE/Audition and you can select between different time scales, amongst which "Samples").

Tigre... i'm confused...

I've always thought that jitter is a concern only at the A/D and D/A interface, where the "time" component gets in. There is also a concept of jitter at the CD physical level (spatial precison of pits/lands placement) and the Red Book gives guidelins on the maximum acceptable jitter of that kind, but I think that a violation of that parameter will cause some kind of read error which eventualy will be corrected or not, but should have no influence on "audible" jitter which should be solely due to imperfection in the clock of the D/A converter.

There is also something strange in your CE graph. In CE sample points are precisely spaced, based on sampling frequency, like the green ones in your graph. How did you managed to get the other red waveform overlapped with the green one? How does it comes that its samples are not evenly spaced?

Hmmmmmmmmmmmmmmm..... is it already April, the 1st where you live???


Cheers!

Sergio

Thanks smz, that answered my question

You're welcome, GenjuroXL!

Sergio

Wow, nice one .
From the number of the post, proving that it was actually created days ago, not on april the 1st, I assume that you edited some kind of old off topic message, and moved it into a new thread with a new content and a new title

Congratulations, you discovered it. Thanks to GenjuroXL for helping... I'll move this to OT now since 1st April is over now here.