PROFESSIONAL RECORDING STUDIO ELECTRONIC EQUIPMENT AND MACHINE INTERFACE PROGRAMS, NAMELY COMPUTER-ASSISTED AUDIO MIXING SYSTEMS COMPRISING A MIX CONTROLLER AND AN AUDIO MAINFRAME, CONSISTING OF AUDIO PROCESSING MODULES, CONTROL MODULES, BAR GRAPH METERS, AUDIO ATTENUATORS, PRE-AMPLIFIERS, EQUALIZERS, AUXILIARY SENDS, FADERS, BUS AMPLIFIERS, MONITOR OUTPUTS, HEADPHONE AMPLIFIERS, TEST-TONE OSCILLATORS, TALK-BACK MICROPHONES AND READ-ONLY MEMORIES (ROMS)