The acoustics in auditoria are determined by the properties of both the direct sound and the later arriving reflections. If electroacoustic means are used to repair disturbing deficiencies in the acoustics, one has to cope with unfavorable side effects such as localization problems and artificial impressions of the reverberant field (electronic flavor). To avoid those side effects, the concept of electroacoustic wave front synthesis is introduced. The underlying theory is based on the Kirchhoff–Helmholtz integral. In this new concept the 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.

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Wave field synthesis is a reproduction technique developed at TU Delft, that enables the generation of high-quality three-dimensional spatial sound fields. The benefit of the method is that spatial impressions are highly independent of the position of the listeners within a large listening area. In short, the method uses a limited number of audio channels that are reproduced by generating plane and spherical wave fields with arrays of loudspeakers that surround the listening place. Applications include spatial sound reproduction in the home and in cinemas, sound reinforcement in theaters, teleconferencing with large video screens, and variable acoustics.

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Sound propagation in enclosed spaces is characterized by reflections at the boundaries of the enclosure. Reflections can be wanted in the case when they support the direct sound or give a feeling of envelopment or they can be unwanted when they lead to echoes and colouration. When measuring multiple impulse responses in an enclosed space along an array the reflections can be mapped to the reflecting objects. Similar to seismic exploration, medical diagnostics, and underwater acoustics, an image of the reflecting objects is obtained in terms of reflected energy. The imaging process is based on inverse wave field extrapolation with the Kirchhoff–Helmholtz and Rayleigh integrals. The inverse of the imaging process recreates the measured impulse responses from the image and it allows one to remove or alter reflecting objects in the image and investigate their influence on the wave field in the enclosed space in a physically correct way. This can be verified by reimaging the altered wave field. Preliminary results from listening tests for the perceptual evaluation are presented. They indicate that the influence of a reflecting object can only be perceived in its close proximity.