Selective Audio Signal Cancellation

Abstract

Selectively canceling signals at specific locations within an acoustical environment with multiple listeners is of significant importance for home theater, automobile, teleconferencing, office, industrial, and other applications. The traditional noise cancellation approach is impractical for such applications because it requires secondary sources to “anti-phase” the primary source, or sensors to be placed on the listeners. In this chapter we present an alternative method for signal cancellation by preprocessing the acoustical signal with a filter known as the eigenfilter [103, 104]. We examine the theoretical properties of such filters, and investigate the performance (gain) and tradeoff issues such as spectral distortion. Sensitivity of the performance as a function of the room impulse response duration (reverberation) modeled in the eigenfilter is also investigated.