🚀 go-pugleaf

Kit-pui Wong wrote:
> 
> Some people with "golden ears" claim that there are great
> differences between an original CD and its digital CDR copy.
> 

I haven't heard anybody here claimed themselves to have a pair of 
"Golden ears". And it doesn't need a "Golden ear" to hear it.

Many cheap CD Recorders cannot make a good copy of the original, I
know my Ricoh is not good in doing so. I've heard some from Plextor
and they are much better than the ones from my Ricoh. Some people
said Yamaha is also very good.

> Is there any **theoretical** ground about the difference ?
> In digital world, information on CD are always O's and 1's.

Yes, theoretically. But there are a lot of uncertainties in practise.
I also want to live in the ideal world, but the ideal world does not
exist up till now.

> A digital copy of an audio CD should store the same stream
> of 0's and 1's and therefore produce exactly identical
> output.
> Then, what makes the differences (if any) ??
> 

Not always the case for audio format. There are always errors on the
disc that need to be corrected, I would believe different patterns of
errors give different sounding CDs.

Do you ever heard of the block error rate ? Some manufacturers are 
producing very low BLER for their CDs, some much higher.

Here is a nanoscopic view of a CD and some descriptions on the 
errors.

http://www.digmbh.de/AppNotes/ODT/ODTMain.html

And that's from my limited knowledge, certainly, I don't exactly know
why, but I can reliably hear a difference between CD and CDR from my
CD Recorder in blind tests.

Felix