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
There was a thread recently, where they thought the copies actually sounded "better". (CDR's don't use aluminum as the substrate, it's a photosensitive chemical layer). I don't think there are any simple answers to your questions! It's definitely not as simple as reading "either ones or zeros", either..........................Peruse The Complete Guide to Highend Audio, familiarize yourself with the finer points, and then e-mail a few high end digital manufacturers for their thoughts on this (but don't ask dumb questions, and don't hound them too much).
Hi Jeff; I'm surprised to see your comments re: poor quality CD copies. I have a Pioneer W739 CD-R and my experience has been just the opposite-- I actually get better quality music on the CD-Rs, eg more crisp, more clear, and more dynamic. The differences are not dramatic, but they are noticeable. There was another thread here on AudiogoN that concurred with my observations, and Ramstl postulated that because the CD-Recorder actually burns the pits into the CD-R blank rather than pressing them, they may have sharper edges that are more easily read by the laser mechanism of the player. I am curious to know what aspects of music are lacking or overdone on your copies, and what kind of CD-Recorder you are using. I've used Maxell and Memorex CD-Rs with excellent results. I'll look up the Audio magazine article you refer to. Craig
Craig, I definitely do not believe that the edges are crisper on a CD-R. You have to understand that a CD-R is made while it's spinning, and CD's are stamped. It would be that the stamped ones have the crisper edges (all things being equal...which they aren't). AND, CD-R's use a photosensitive chemical layer, and the holes are bound to have LESS defined edges than the stamped pits, if anything. There might be other advantages, but seculating about it won't get you anywhere. Talk to some experts, and see what they have to say. And carry a CD-R to one of your friends with an electron MICROSCOPE, and compare it with a stamped CD. I think the holes in the chemical layer are bound to have some "wiggle" around their edges, just as photographic film has a grain...but that alone wouldn't necessarily cause poorer sound quality (these wiggles would be very small, compared to the hole the laser burned), and there are complex issues to consider here, that none of us are qualified to discuss...other than subjective opinion and observation........................Right now, it's just like anything else on here...Whatever you like, do it that way, and be happy. Personally, I have no opinion as to whether a copy sounds better, or worse (the CD-R's I have are copies of originals that I did not own, which is the whole point of CD-R in the first place). I'm just happy with the "tweaks" I do to both CD-R's and CD's, and enjoy both.
In response to those that believe the copies they make sound better, I reply that it is impossible. It is only possible to be as good. How can you possibly make it better? How can you upgrade onto your copy what never existed on the source. Now, with that said, I believe the copy can sound better if it is played back on better equipment. Example: If I record from my Meridian 508.24 to my Nakamichi ZX-9 cassette, I could put that CD into a inferior CD player than my Nak and the cassette will sound better than the CD it was recorded from.
I should have mentioned when I posted this originally, the burner I use is an external Yamaha SCSI burner hooked up to my laptop. This set up is great for a computer, but it's entirely possible that a unit intended for audio use would provide better results. Another guy I know, using a different CD burner, discovered the same disappointment, and he's not an audiophile by any means, but he is an engineer and will likely get to the bottom of this mystery. In any event, there is a very real audible differences between the orginal CD and the copied CD's I've made, I think simply ignoring it and enjoying the music isn't bad advice...Jeff