CD Copies...why do they sound worse?


I had a theory that I haven't discarded yet that not all CD blanks are equal in terms of composition. Yes, they all are made of aluminum and polycarbonate, and when you burn a CD you are creating small holes, or dents in the blank. There is the red book standard that must be adhered to, but as in anything else, I'm sure there are better grades of aluminum and poly available, you get what you pay for. Since the laser reads the digital stream by optically scanning the surface of the CD and interpreting either a one or zero, you'd think it's a go/no-go operation. The original and copies do not sound the same, even to the uncritical ear. I thought for a while it may have had something to do with the relative quality of the CD blanks I was using to copy, in other words, the pressing plants simply use a better grade of master CD's. My friend has a contact and we were able to acquire bulk CD blanks from Saturn Disc that makes CD's. No difference, copies still aren't right. I guess we can eliminate the CD blanks for now. Here's where things get a little outside normal thinking in my twisted logic: we know there are error detection and correction schemes used in intrepreting the data on the CD, employed when the bit being read isn't immediately recognizable to the player. Is it possible the home-made copy that was burned using a cheap consumer grade burner, contains more errors? Are the pits burnt in the CD either irregular in shape or depth? Does the laser in these consumer grade CD burner introduce errors? If so, the EDAC is pretty busy, and doesn't always get it right, which would explain a general lack of quality due to latency delays in the data stream while the EDAC does it's work, and in the process is bound to mis-interpret zeros and ones, there is no 100% accurate EDAC. To me, this is a good place to start in terms of understanding the obvious differences in sound quality.
jeffloistarca
Ejlif: Pacific Pro Audio in Seattle, Wa. 1100 Virginia St. Suite # 202 Seattle, Wa 98101 (206)264-9386 Garth is who I deal with. Or go to the apogee web site for a dealer near you' Good Luck, John
Ejlif: I guess I should mention that I'm using a Sony XA7ES (was there flagship until this year) for the source and an Otari CD burner that In purchased from Pacific Pro Audio in Seattle. When I play these back on either the sony or the meridian it is very difficult to tell much difference. When I make an anolog copy (record or tape) the cd copy sometimes sounds better. If you are using a computer to burn with or downloading from the net, I haven't talked with anyone who has had much luck making high quality copies without a huge investment and lots of tinkering.
In my humble opinion the CDR's sound worst because of jitter. The big companies have higher standards then any of the burners. There was a big article in Audiophile about 3 years ago about why the BMG CDs sounded worse then the original company pressings. A detailed comparison was make at the bit level and no differences were detected. Jitter was all that was left. It seems to fit this situation to a T.
Your answer may be found in this article. http://www.stereophile.com/shownews.cgi?790