Acoustic control by wave field synthesis
A. J. Berkhout, D. de Vries, and P. Vogel
Delft University of Technology, Laboratory of Seismics and Acoustics, P.O. Box 5046, 2600 GA Delft,
The Netherlands
(Received 13 November 1991; revised 21 September 1992; accepted 4 January 1993 )
The acoustics in auditoria are determined by the properties of both the direct sound and the later
arriving reflections. Ifelectroacoustic means are used to repair disturbing deficiencies inthe
acoustics, one has to cope with unfavorable side effects such as localization problems and
artificial impressions ofthe reverberant field (electronic flavor). To avoid those side effects, the
concept of electroacoustic wave front synthesis introduced. The underlying theory is based on
the Kirchhoff-Helmholtz integral. In this new concepthe wave fields of the sound sources on
stage are measured by directive microphones; next they are electronically extrapolated away
from the stage, and finally they are re-emitted in the hall by one or more loudspeaker arrays. The
proposed system aims at emitting wave fronts that are as close as possible to the real wave fields.
Theoretically, there need not be any differences between the electronically generated wave fields
and the real wave fields. By using the image source concept, reflections can be generated in the
same way as direct sound.
PACS numbers: 43.55.Jz, 43.55.Lb