Spatial sound reproduction with wave field synthesis

Abstract

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.

Contribuciones a la implementación de sistemas Wave Field Synthesis.

“…Si la superficie S degenera en un plano que separa elárea de reproducción delárea en la que se encuentran las fuentes sonoras (véase la Figura 2.15 b), la ecuación (2.8) se puede reducir a dos ecuaciones distintas, las denominadas Integrales de Rayleigh I [Boone and Verheijen, 1993] y II [Berkhout et al, 1993]:…”

“…Esto es, se aplica un peso menor a los altavoces cercanos al extremo del array. De esta forma la difracción disminuye drásticamente pero a costa de reducir la zona efectiva de escucha [Sonke, 2000;Boone et al, 1995].…”

Application of sound source separation methods to advanced spatial audio systems.

“…The first Rayleigh integral (Rayleigh I ) states that the wave field in the listening half space can be reconstructed from the original sound field by measuring only the particle velocity in the measurement plane and using these measurements as source signals for a distribution of monopoles on the reproduction plane [132]: 8) or in its discretized form:…”

“…where G is the free space Green function, given by 5) and R = |r − r s |. Equation (5.4) states, considering the interior problem, that the acoustic field in V generated by the events outside the surface S can be computed uniquely by replacing these events with a distribution of simple monopole surfaces over P (r)G(r|r s ) and summing up their contributions over S. Thus, an arbitrary acoustical wave field can be recreated within a source-free volume V by secondary sound sources distributed on a closed boundary surface S. The latter is expressed by the so-called Kirchhoff-Helmholtz integral:…”

“…However, although this may be considered as a WFS "avant la lettre", it misses the physical insight and background that forms the basis of the real invention. It was not until the late 80s when the theory of WFS was introduced in the works published by the Delft University of Technology [3][4] [5] and which led to the first WFS prototypes.…”