v7.0, 20040922, me
Sunday, October 31, 9:00 am 10:30 am
Session P HIGH RESOLUTION AUDIO
Chair: Mark Sandler, Queen Mary, University of London, London, UK
P-1 A New Method of Applying High Levels of Dither to Delta-Sigma ModulatorsJames Angus, University of Salford, Salford, Greater Manchester, UK
This paper presents a new a new method of applying high levels of dither to sigma-delta modulators. In particular, it clarifies the position of the overload point in one-bit sigma-delta modulation systems and presents several overload control methods with comparisons of their efficacy. It then goes on to examine the problem of applying dither to one-bit systems and describes a new approach for applying high levels of dither. It also examines the effect of different dither probability density distributions and shows that simple bilevel dither can be effective at lower levels than other probability density distributions. It presents results that show that dither can be applied at a high enough level to be effective in one-bit sigma-delta modulation systems.
Convention Paper 6296
P-2 Scaleable Multichannel DSD CodingMalcolm Hawksford, University of Essex, Colchester, Essex, UK
DSD is a 1-bit coding scheme based upon sigma-delta modulation. In the commercial realization of this technology exploiting DVD optical disc storage, six discrete channels are accommodated each with a constant bit rate of 2.8224 Mb/s, a specification that cannot be changed within the context of the SACD release format. However, a method of embedding additional data in the DSD bitstream is shown to be feasible with the aim of increasing the number of channels to twelve. The technique retains full compatibility with SACD and only requires modest processing to decode an additional six channels.
Convention Paper 6297
P-3 Perceptual Discrimination of Very High Frequency Components in Musical Sound Recorded with a Newly Developed Wide Frequency Range MicrophoneKimio Hamasaki, NHK Science & Technical Research Laboratories, Tokyo, Japan, Kyushu University, Fukuoka, Japan; Toshiyuki Nisiguchi, NHK Science & Technical Research Laboratories, Tokyo, Japan Kazuho Ono, NHK Science & Technical Research Laboratories, Tokyo, Japan; Akio Ando, NHK Science & Technical Research Laboratories, Tokyo, Japan
Subjective evaluation tests on perceptual discrimination between musical sounds with and without very high frequency (above 20 kHz) components have been conducted. To make a precise evaluation, the test system is designed to exclude any influence from very high frequency components in the audible frequency range. Moreover, various sound stimuli are originally recorded by a newly developed very wide frequency range microphone in order to contain enough components in very high frequency range. Tests showed that some subjects might be able to discriminate between musical sounds with and without very high frequency components. This paper describes these subjective evaluations, and discusses the possibility of such discrimination as well as the high resolution audio recording of music.
Convention Paper 6298