From Longman Dictionary of Contemporary Englishquadraphonicquad‧ra‧phon‧ic, quadrophonic /ˌkwɒdrəˈfɒnɪk◂ $ ˌkwɑːdrəˈfɑː-/ adjective TCBTCRusing a system of sound recording, broadcasting etc in which sound comes from four different speakers at the same time → mono, stereo
Examples from the Corpus
quadraphonic• However, it was not possible to get any quadraphonic effect from the record, nomatterwhich system was tried.• When it tells our brains which way our heads are pointing, it affects our perception of stereo and quadraphonic sound. 