Bit perfect copies

Thanks for the information chanifin. Would you have the web address of Eaxact Audio Copy?
FC

Check out www.etree.org for links to EAC and other software.

No such thing as bit perfect. To make my point Stereophile had an article about BMG's quality. As you may recall, BMG remarkets CDs to clubs. Stereophile did a comparision between the original CDs from RCA, Mercury and other companys and the BMG pressings. Result was the BMG CDs were digital perfect but didn't sound as good.

To cut this long story short. The bits layed down were identical as will be those you make at home in general. The problem is the timing. The jitter and phase of the bits as they clock into the D/A add distortion to the sound. CD burners are not as good as BMG's so you will be degraded even more.

How do you overcome this? You don't.

I don't think I follow what you're saying - clocking the bits (samples) into the D/A comes well after the reading of the disc, so how does the source (CD vs. CDR) affect the quality at the point of putting it into the DAC? Are you suggesting that a CDR gets read "wrong" despite being bit-perfect where the CD gets read "right"? I also don't understand the concept of "bit phase". Would all these issues go away if the whole CDR was read into RAM before playback began?

I'm very open to the concept that CDRs are somehow inferior to the original CD, though it hasn't been my experience and runs counter to my technical understanding (which undoubtedly could be enhanced). I don't think Stereophile saying CDRs "didn't sound as good" really establishes much as there is an inherent bias there - if it really is possible to make 50 cent copies of CDs that are indistinguishable from the original (using a cheap computer no less), that's not good for Stereophile's business. I'm not saying their viewpoint can't be right, just that it doesn't mean much coming from them.

To answer the original poster's question, I'd use a computer and some easily obtainable freeware or shareware to make the copies. Cheap, easy and effective. -Kirk

Kthomas I agree with you about cheap and effective. But not perfect. There is jitter introduced at all stages of the digital to analoge process. For the digital to digital I was not referring to the error encoding of the original being changed. I'm actually talking about clock in the CDR that governs the placement of the copied bit on the cdr media. When it is not dead on perfect (parts per billion or less) The the decoded signal on playback has phase errors in the analog signal. Ideally even if you had an imperfect clock that would repeat its errors reliably and it was used to burn the CDR and play it back you would have no error in phase in the analog output. But you don't.

Also one other issue. No player reads every bit perfectly from the original play. That's why we have error encoding built in to the process. So you have to read every bit perfectly (typically 700K of them) and then place them back on the CDR without a signal one out of place. If the CDR has a flaw in its manufacture or the laser varies in intensity or location.//error.