Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!philabs!micomvax!micomz!softech From: softech@micomz.UUCP Newsgroups: net.audio Subject: CD in cars and other MYTHS ! Message-ID: <163@micomz.UUCP> Date: Tue, 7-Jun-83 23:35:06 EDT Article-I.D.: micomz.163 Posted: Tue Jun 7 23:35:06 1983 Date-Received: Wed, 8-Jun-83 19:10:44 EDT References: hou5e.494 Lines: 24 I was reading all the debate about CD players in cars, and it occured to me that we all forgot one VERY important thing: Playing a CD in a moving vehicle would be about as difficult as playing a standard record (with stylus and all). The tracking system in CD players is so precise and so fragile that it would be impossible to design one small enough and strong enough to resist the G-forces involved without losing the necessary precision. Remember that the little laser beam must be kept ON TRACK and IN FOCUS at all times. Now we are talking about tracks that are only 1/20 th of a normal record groove in width, and there is no mechanical contact to do the tracking with! Its all done optically by a complex servo mechanism that analyses the shape of the laser on the record surface. Minute fluctuations due to hole centering errors or warpage of the surface are corrected by ultra-fast voice-coils that hold the focusing apparatus (remember the little devil SPINS!). A small bump on the road would easily cause several seconds of "errors", if not complete jumping of tracks. So, for all of you waiting to trade-in your old Delco... (By the way, the same goes for the Walkies fans, unless you go real easy on your roller skates...) Richard "Ears" Blouin. !philabs!micomvax!micomz!softech