Barry Willis

For the 109th convention of the Audio Engineering Society, the main floor of the L.A. Convention Center was transformed into a bazaar of new tools for audio professionals—but the panel discussions upstairs were where the real action took place. On Friday, September 22—just an hour before researchers Dr. Stanley Lipshitz and John Vanderkooy of Ontario's University of Waterloo presented a paper offering a mathematical proof for the "imperfectability" of one-bit delta-sigma recording systems—Sony Corporation issued a clarification of the technical standards for its Direct Stream Digital technology, the basis of the Super Audio Compact Disc. DSD, it now appears, is a one-bit technique as it applies to consumer playback systems, but uses a multi-bit PCM quantizer [presumably within a delta-sigma converter negative-feedback loop; see an article on this subject in the forthcoming November issue of Stereophile—Ed.] at the recording and mastering ends of the business. (The Lipshitz/Vanderkooy paper is available as AES preprint #5188.)