Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site hou4b.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!hao!hplabs!tektronix!uw-beaver!cornell!vax135!ariel!hou4b!mat From: mat@hou4b.UUCP (Mark Terribile) Newsgroups: net.audio Subject: Re: Sheffield CDs and why they sound bad Message-ID: <1183@hou4b.UUCP> Date: Thu, 11-Oct-84 12:54:52 EDT Article-I.D.: hou4b.1183 Posted: Thu Oct 11 12:54:52 1984 Date-Received: Sat, 13-Oct-84 03:44:27 EDT References: <46@vice.UUCP> Organization: AT&T Information Systems Laboratories, Holmdel, NJ Lines: 30 >A final comment - I like the idea of compressing CDs, but more for stereo >system protection than for ultimate dynamic range. If this is done, the >compression should be multiband and the level of compression indicated by an >explicit control track instead of by sensing the level of the compressed >output and supposedly ``undoing'' the change, as is done now. This would >reduce system distortion to levels approaching -80dB(MOL) rather than the >-40 to >-60dB(MOL) possible with today's systems (such as dbx), and could be >easily implemented by an extra control word in the CD bit stream with >appropriate sorting in the player. Of course, this would entail perhaps a >30% in playing time, about the same as 20 bit PCM but a whole lot more >manufacturable. I don't think it would have to cost 30% in play time; it would seem that the envelope used for compression would need a bandwidth of only 100 Hz or so and even 1f you used 16 bits for the compression amount, you would be taking less than 1/2 of 1% off the usable bandwidth. But for listenability reasons, especially in cars, you might very well want to be able to NOT decompress the signal. This would be most useful if the mastering engineers and the performers/writers had a say in what amount of compression was used. I like this idea, mainly because IF compression is needed, it ought to be in the hands of the artist. Let the artist decide how he will ``compose'' for the noisy environment. -- from Mole End Mark Terribile (scrape .. dig ) hou4b!mat ,.. .,, ,,, ..,***_*.