Apparatus for reproducing sound having a realistic ambient field and acoustic image is used in a stereophonic sound reproduction system having a left channel output and a right channel output. A right main speaker and a left main speaker are disposed at right and left main speaker locations, respectively,...http://www.google.de/patents/US4569074?utm_source=gb-gplus-sharePatent US4569074 - Method and apparatus for reproducing sound having a realistic ambient field and acoustic image
