Electronic Journal Technical Acoustics ISSN 1819-2408

Milind N. Kunchur

Audibility of temporal smearing and time misalignment of acoustic signals

language: English

received 19.07.2007, published 29.08.2007

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Erratum 08.04.2008 (PDF, 20 kb, ZIP)

ABSTRACT

Misalignment in timing between drivers in a speaker system and temporal smearing of signals in components and cables has long been alleged to cause degradation of fidelity in audio reproduction. It has also been noted that listeners prefer higher sampling rates (e.g., 96 kHz) than the 44.1 kHz of the digital compact disk, even though the 22 kHz Nyquist frequency of the latter already exceeds the nominal single-tone high-frequency hearing limit of about 18 kHz (i.e., an angular frequency limit of 113,000 rad/s). These qualitative and anecdotal observations point to the possibility that human hearing may be sensitive to temporal errors, that are shorter than the reciprocal of the limiting angular frequency (about 9 microseconds), thus necessitating bandwidths in audio equipment that are much higher than hearing limit frequency in order to preserve fidelity. The blind trials of the present work provide quantitative proof of this by assessing the discernability of time misalignment between signals from spatially displaced speakers. The experiment found a displacement threshold of about 2 mm corresponding to a delay discrimination of about 6 microseconds.

Keywords: time, temporal, align, alignment, smearing, resolution

18 pages, 6 figures

Сitation: Milind N. Kunchur. Audibility of temporal smearing and time misalignment of acoustic signals. Electronic Journal “Technical Acoustics”, http://www.ejta.org, 2007, 17.

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Milind N. Kunchur received his Ph.D. degree in Physics from Rutgers University in 1988. He is currently a Professor in the Department of Physics and Astronomy at the University of South Carolina, before which he held appointments at Oak Ridge National Laboratory and at the Wright Patterson Air Force Base. Professor Kunchur has taught a course on Musical Acoustics for many years. He is interested in understanding the human hearing mechanism and how its limits relate to fidelity in sound reproduction. He is a member of APS, AES, ASA, and SCAS professional societies. The web site: http://www.physics.sc.edu/kunchur contains further information and a list of publications. e-mail: kunchur(at)sc.edu