Methods for active control of sound field in terms of the properties involved in Kirchhoff-Helmholtz boundary integral equation

摘要

The application of Kirchhoff-Helmholtz boundary integral equation leads to the representation of sound field in an arbitrary region with an arbitrary boundary by means of sound pressure and its derivative on the boundary, and direct component of sound from the sources inside the region. This representation has some interesting properties. For instance, when this representation is adopted in active control of the sound field under the condition that there exists no sound source inside the control region, the sound field in the control region can be controlled in terms of the sound pressure and/or its derivative on the boundary of the region. Based on such a viewpoint, methods for the active control of sound field in terms of the Kirchhoff-Helmholtz boundary integral equation are overviewed, then the equalization of the sound field to the free field proposed by the authors based on the Kirchhoff-Helmholtz boundary integral equation is briefly introduced. The features and the problems of the proposed method are also mentioned.