Gramophone PA PA system Victrola audio sound system audiophile binaural system bullhorn cartridge ceramic pickup changer crystal pickup derived four-channel system discrete four-channel system four-channel stereo system hi-fi hi-fi fan high-fidelity intercom intercommunication system jukebox magnetic pickup monaural system mono needle nickelodeon phonograph photoelectric pickup pickup public-address system quadraphonic sound system radio-phonograph combination record changer record player sound reproduction system sound truck squawk box stereo stylus system tape deck tape recorder tone arm transcription turntable turntable