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Green-'ening' CD's

In another post on CD of marking CD's. In particular, he mentioned that marking CD edges increases the read error rate. He concludes this is bad.

While I don't doubt the accuracy of the investigation, nor the assessment that increassed error correction means a deviation from the intended signal, I do question if this is bad, per say. I base this on the audible improvements that many note by employing this tweak.

I hypothesize that the increased error read rate acts as a dither effect - something used in the Rotel 991 (?) and some other players with a positive sonic effect. Even if my hypothesis is rejected (probably by the next post :), it is still odd that a decrease in signal integrity leads to improved sonic performance (according to many). I would be curious what the group thinks about this.

Best,
mprime
6 responses Add your response
david_d
83 posts
 

Hi Mprime!
I use it on my CD's (and it must not be exclusively green, black works also) with positive results.
As far as i know it has to do with absorbing unwanted light reflections of the laser beam. Less (of these unwanted) light reflections through the Compact Disc and the Laser can do it job better - to (over)simplify things. It actually sounds pretty logical to me and "explains" the sonic gain. I've also seen article's that support this...
Best regards!
nrchy's avatar
nrchy
2,124 posts
 
I would not disagree with Seans conclusion, but I have to say my experience was different. I have found anywhere from a big improvement to no difference at all. I have never experienced a decrease in sound quality.
Different results do not mean anyone is wrong! Experience is experience, and it isn't a right or wrong area. In my experience Sean know more than most of the people posting here!
eldartford
4,262 posts
 
Error "correction" means that after the process is done the information is identical to what was there before the error occured. Therefore inaudible. Audible effects will exist only when the error rate exceeds the capability of the encoding scheme, and some kind of "fall back" interpolation process is used. If that is happening, you need a new disc or a new player, or both.
mprime OP
92 posts
 
Bomarc,

I'm inclined to take you up on #2 :-) Not looking for *only* a technical explanation as I know there may not be one. Still, there are plenty of bright folks who are part of this forum who's opinion I'd like to hear. If it is a 'dither effect' then there are some interesting conclusions/implications which may be drawn.

This sure isn't intended to be flame bait :-(

Best,
bomarc
501 posts
 
Well, there are three possible explanations:

1) Sean's technical explanation is wrong.

2) Some audiophiles prefer an error-corrected signal to the "original."

3) Some audiophiles imagine an improvement that isn't really there.

I would guess that the increase in error rate would be minor, but I haven't tested this. On the other hand, there is no other known or even scientifically plausible reason why marking CDs should have any effect whatsoever on the signal. (Your dither theory being a fine counterexample.)

You're asking for a technical explanation. There is no technical explanation. If you believe that marking your CDs makes them sound better, then mark them. Leave the science to the scientists.
mprime OP
92 posts
 
Don't know what happened to the first line of my post. Meant to be:

In another post on CD treatments, in particular, marking the edges of CDs with a green pen, Sean mentioned that such markings can increase the read error rate. He concludes this is bad....

Rest reads as above.

Strange
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