Applied Acoustics 36 (1992) 327-333 Technical Note Teleconferencing System Using Head-Related Signals* J. E. West, J. Blauert: & D. J. MacLean§ AT & T Bell Laboratories, Murray Hill, New Jersey 07974, USA (Received 22 November 1991; accepted 2 March 1992) ABSTRACT Teleconferencing over electroacoustic transmission systems, using signals picked up by microphones located in the ear canals of natural or artificial heads, is examined. Such systems can, to a large extent, provide natural spatial separation of sound images when listening over earphones. The earphones must be adjusted to the transfer function of the individual listener's external ears. Without the desired transfer function or filter, errors in spatial perception occur, such asfront-to-back reversals or elevation of the perceived sound image. We describe a system which automatically achieves the desired filtering by the arrangement of the play-back transducers or earphones, and by the proper selection of the microphones. The earphones are arranged on the listener's head in such a way that they stimulate the external ears similar to a frontal-plane sound wave. As pick-up transducers, the system uses small electret condenser microphones that can be inserted into the ear canal of natural or artificial ears. 1 INTRODUCTION Head-related electroacoustic transmission systems 1-4 provide an impress- ive spatial separation of the sound images. This is achieved by a careful * Based on work carried out during a sabbatical stay by Blauert at the AT&T Bell Laboratories in 1976. ~/Present address: Lehrstuhl f'dr Allgemeine Elektrotechnik & Akustik, Ruhr-Universit~it Bochum, D-30 Bochum 1, Germany. §Present address: Rt. 7, Box 463, Franklin, North Carolina 28734, USA. 327 Applied Acoustics 36 (1992)----~ 1992 Elsevier Science Publishers Ltd, England. Printed in Great Britain