Friday, October 10 4:00pm 6:00 pm
Session D High-Resolution Audio
D-1 Perceptual Discrimination between Musical Sounds With and Without Very High Frequency ComponentsToshiyuki Nishiguchi, Kimio Hamasaki, Masakazu Iwaki, Akio Ando, NHK Science & Technical Research Laboratories, Tokyo, Japan
We conducted subjective evaluation tests to study perceptual discrimination between musical sounds with and without very high frequency components (above 21 kHz). In order to conduct strict evaluation tests, the sound reproduction system used for these tests was designed to exclude any leakage or influence of very high frequency components in the audible frequency range.
Most of the sound stimuli used for the evaluation tests were newly recorded by the authors to maintain the highest quality for proper sound reproduction. The subjects were selected mainly from professional audio experts and musicians. The results showed that we can still neither confirm nor deny the possibility that some subjects could discriminate between musical sounds with and without very high frequency components.
D-2 Parametrically Controlled Noise Shaping in Variable State-Step-Back Pseudo-Trellis SDMMalcolm Hawksford, University of Essex, Colchester, Essex, UK
Progress is reported in parametrically controlled noise shaping Sigma Delta Modulator (SDM) design. As this SDM structure (introduced by the author at AES 112th Convention) can obtain a higher SNR than normal SDM structures, Philips Research Laboratories have questioned whether further improvement could be obtained using techniques inspired by the Trellis SDM. Simulations are used here to illustrate the performance of a parametrically controlled pseudo-Trellis SDM, which is believed to be the first disclosure of its type. The technique uses a variable state step back approach to moderate loop behavior that is shown to achieve robust stability in the presence of aggressive noise shaping and high level signals. Comparisons are made with traditional SDM structures and LPCM systems.
D-3 A Universal Interface on Cat-5 Cable for High-Resolution Multichannel Audio InterconnectionMichael Page, Gary Cook, Peter Eastty, Eamon Hughes, Mike Smith, Sony Oxford, Eynsham, Oxford, UK
Super Multichannel Audio Connection (SuperMAC) is an enhancement of the existing Multichannel Audio Connection for Direct Stream Digital (MAC-DSD) to support PCM audio formats, extending the unique benefits of the technology to a universal range of studio audio applications. The link provides full duplex multichannel audio connections for DSD or 24-bit PCM at sample rates up to 384 kHz, plus high-quality clock signals and auxiliary data. It features error correction and deterministic latency as low as 45 microseconds, and the connection medium is a standard structured wiring cable. The specification is being submitted to the AES Standards Committee with a view to open standardization.
D-4 The Effects and Reduction of Common-Mode Noise and Electromagnetic Interference in High-Resolution Digital Audio Transmission SystemsJon Paul, Scientific Conversion, Inc., Novato, CA, USA
High-resolution digital audio systems are susceptible to various sources of electromagnetic noise from the environment, especially crosstalk from adjacent cables. The noise can induce errors and increase jitter in the recovered clock signal. We discuss the most important noise sources and their characteristics. Next, we analyze the noise susceptibility of typical transmitter and receiver circuits. Test results are provided for a system with induced common mode noise. The paper concludes with design and application considerations.