fish@ihu1g.UUCP (Bob Fishell) (05/03/84)
(oo)
Having seen a recent group of articles about cleaning CDs on the
net, I began to wonder just how critical this was. I had replied
that a CD should be treated like a good camera lens, i.e., keep
fingerprints and dust off.
Anyway, I thought I'd try an experiment. I took out my least-favored
CD and proceeded to place a large, very greasy thumbprint across the
playing surface. I did this by immersing my thumb in sausage grease
left over from dinner and wiping off just the excess, so you can imagine
what this print was like. I tried to play the disc in my Technics PL-7,
and got silence. Apparently, I had messed up the surface enough to
completely shut down the error correction circuitry.
I removed the disc and cleaned it with the same lens cleaning solution
I use on my eyeglasses. The enormous print gone, the disc played
perfectly clear through. Repeating the experiment with a normal,
body-oil fingerprint, the error correction circuit had no problem
this time, and the disc still played perfectly.
Moral: error correction is good, but not magic. Try to keep the
disc clean! I think that scratches are probably the most harmful
thing you can get on a CD, but I was not about to try it. I don't
disfavor my test disc THAT much.
To Phil R. and the rest of the anti-CD crowd: try this experiment with
an analog disc and post the results to the net... :-)
--
Bob Fishell
ihnp4!ihu1g!fishron@brl-vgr.UUCP (05/04/84)
You seem to be of the opinion that Error Correction is the thing that is keeping fingerprints from destroying your audio quality. The major thing however is the laser. Focused on the substrate and not on the surface, it is less vunerable to surface crud. Ever see the dust on the lens in the photographs you've taken? -Ron