can be synthesized from such elementary waves. In practice, a computer controls a large array of individual loudspeakers and actuates each one exactly by the time and level at which the desired virtual wavefront would pass through its point. In that way, from a mono signal source, a genuine wave front of a sound source may be restored.

The basic procedure was developed in 1988 by Professor A.J. Berkhout at the Delft University of Technology. Its mathematical basis is the Kirchhoff-Helmholtz integral.