Inventors:
Donald E. Norgaard - Mountain View CA
Assignee:
Nortech Laboratories Ltd. - San Francisco CA
International Classification:
H04M 100
Abstract:
An improved method and apparatus for reproducing sound includes a third channel which is derived from the pair of signals representing traditional left and right stereophonic channels and which represents a linear algebraic difference between such a pair of signals. A third loudspeaker associated with the third channel povides acoustic radiation as a supplement to acoustic radiation from two laterally-spaced loudspeakers normally used to reproduce respective left and right signal channels. Acoustic radiation from the third loudspeaker is toward a preferred listening region and in a direction substantially opposite to that from the two laterally-spaced left and right loudspeakers which are positioned and oriented to provide essentially codirectional acoustic radiation toward the preferred listening region. Preferred embodiments incorporate amplifier and matrixing circuitry to derive the third channel signal and to adjust the level of sound radiated by the third loudspeaker relative to that of sound radiated by left and right loudspeakers.