Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!decvax!genrad!mit-eddie!godot!ima!inmet!muller From: muller@inmet.UUCP Newsgroups: net.audio Subject: Re: re: West of Oz CD Message-ID: <1727@inmet.UUCP> Date: Tue, 16-Oct-84 02:36:19 EDT Article-I.D.: inmet.1727 Posted: Tue Oct 16 02:36:19 1984 Date-Received: Wed, 17-Oct-84 19:55:01 EDT Lines: 0 Nf-ID: #R:decwrl:-387200:inmet:2600110:000:1987 Nf-From: inmet!muller Oct 14 22:33:00 1984 *** Nice experiment, trying the blind comparison. A few comments, questions, and suggestions: (1) You say analog to digital sounds good, but digital to analog sounds bad. Then you ask why. Umm...seems to me that this is a bit of a generalization. As I try to answer this to myself, and as I ponder the results of your PCM test, I find lots of room for any specimen to be poorly done, but no reason to explain why A to D is ALWAYS better than D to A. (2) With regards your piano and guitar recordings, why not try the same setup, recording the same stuff into a GOOD analog tape machine? THEN do a comparison of the two recordings PCM -> VCR vs. Analog tape. You will probably hear some differences, but the audible features you describe as characteristic of digital may be present to some extent in your analog recording. What might they be? Well, maybe what you heard is exactly what your mics heard. A look at most mics' spec sheets shows definitely non-flat frequency response. They were designed (evolved?) to sound good, not necessarily have flat-looking response. Perhaps they compensate for other features of the recording medium, features which digital systems don't quite duplicate? (Can we assume there was no real loss of information in the VCR, such as lost bits that were only poorly "fixed" on playback? (I don't know much about how VCR's work.)) (3) Have you, or anyone else, dont this same PCM -> VCR test using pink noise and an analyzer? Yeah, I know, you can't really expect .5 dB precision from this, but it sounds like we are talking about more than this anyway. ... Looking objectively at your results, you have shown that the digital process itself is not really making things sound bad. So where then is the problem? It must elsewhere in the recording process, either the total composite frequency response, or the dynamic range, or non-linearities or so Thus it would be good to try the other recordings I suggested, just as another control.