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

Showing 3 responses by garfish

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
Hi Hunter; When I first got my Pioneer W739 CD recorder, I was convinced that CD copies actually sounded BETTER than originals (actually different, and a sound I liked), but I am willing to back off that original assessment and now say that the copies sound just as good. The main reason I got a CD-R was to make compilation CDs. I have made a set of four CD-Rs that I call "Blues and Soul, Nice and Slow". This set was made from 50-60 different CDs chosen from my blues and soul collection of about 250-300 CDs. To select the songs, determine recording levels and do a perfect job of recording these songs on 4 CD-Rs took me weeks. I have 15-17 songs on each CD for a total of 70+ minutes of music per CD, or 280 minutes of MY FAVORITE blues and soul songs. My point: I bought all of the original CDs and recorded them on the (more expensive) consumer audio/music CDs, and I do not consider this "stealing", in fact I created something musical that didn't exist before, and I would place a value on each of these CDs of around $100.-- to me. These compilations do not exist anywhere else in the world, and IMO this is the real value of CD-Rs. I have done other compilations but nothing approaching the complexity of these blues CDs. I occasionally "burn" a copy for use somewhere else or for my daughter-- something she wouldn't buy any way. CD-Rs really are effectively no different than cassette recorders, which I also have. I am not, and refuse to "whine" about this. Respectfully. Craig.