Sound Sketch: Shaping sound in space and time using loudspeaker arrays

Abstract

The control of the spatial distribution of noise and sound has been widely investigated for achieving passive and active noise control. By extending the concepts of active noise control and zones of quiet, one can sketch sound, i.e., synthesize sound fields of various shapes using loudspeaker arrays to achieve the desired sound quality in a finite zone of interest. Sound sketching involves reproducing existing sound fields as well as creating new shapes of sound fields that can scarcely be observed in common acoustical spaces. In this lecture, two representative problems related to sound shaping are presented: The synthesis of a personal sound zone, and the manipulation of virtual sound sources. Through the shaping of sound in space, sound fields can be focused over a selected area to form a personal sound zone within which a person hears only a specified sound program without being disturbed by other unwanted programs. In addition to focusing sound fields, it is possible to control a sound wavefront to produce virtual sound sources with various radiation patterns in a source-free space. The underlying array signal processing theories, developed since 2000, are introduced in regard to practical systems implemented for various applications. The novel paradigm for sound field control systems, the Sound of Things, is introduced with a sound sketch interface devised to facilitate gesture-based interaction between a person and a sound field.