Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site petrus.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!bellcore!petrus!karn From: karn@petrus.UUCP Newsgroups: net.audio Subject: SR article on CD filtering Message-ID: <386@petrus.UUCP> Date: Sun, 30-Jun-85 00:41:40 EDT Article-I.D.: petrus.386 Posted: Sun Jun 30 00:41:40 1985 Date-Received: Mon, 1-Jul-85 06:43:44 EDT Distribution: net Organization: Bell Communications Research, Inc Lines: 22 The July issue of Stereo Review has a very good (for an audio magazine) article comparing digital and analog filtering techniques. It provides an overview of the two methods and how digital filtering eases the task of constructing the (inevitable) final analog filter. The conclusion? The author prefers digital filters -- not due to any audible differences in phase response, but because digital filters ought to be more reliable and may also provide a flatter amplitude response. The following excerpt is also of interest. Can anybody provide a more complete citation to the JAES article? "The upshot of all this is that it has yet to be conclusively demonstrated that any of the differences in high-frequency phase response between analog and digital output filters are audible, audiophile opinions notwithstanding. Carefully conducted tests reported in the Journal of the Audio Engineering Society show that listeners cannot detect the operation of *either* type of filter when impulses are being reproduced, even when several of the filters are connected in series! Earlier experiments showed that listeners could not detect the presence of steep-cutoff analog filters when the cutoff frequency is as high as 20,000 Hz, as in CD players." Phil