ASA 124th Meeting New Orleans 1992 October

4aAA6. Wave-front synthesis: A new direction in electroacoustics.

A. J. Berkhout

Lab. of Seismics and Acoust., Delft Univ. of Technol., P.O. Box 5046, 2600 GA Delft, The Netherlands

The acoustics in auditoria is determined by the properties of both direct sound and reflections. If electroacoustic means are used to optimize the acoustics, one has to cope with unfavorable side effects such as localization problems and artificial impression of the reverberant field. To avoid those side effects, the concept of electroacoustic wave-front synthesis is introduced. The underlying theory is based on the Huygens--Rayleigh integral. In this concept, the wave fields of the sound sources on stage are measured by directive microphones; next they are extrapolated by means of an electronic processor, and finally, they are re-emitted in the hall by one or more loudspeaker arrays. Depending on the processor design, the wave-front systems can be used for direct sound enhancement, for simulation of discrete early reflections, or for generation of reverberation. Application of the wave-front synthesis concept also opens the door to a new approach of sound recording and reproduction.