Audio mixers; sound mixers; audio amplifiers; sound amplifiers; guitar amplifiers; musical instrument amplifiers; stereo amplifiers; audio speakers; loud speakers; loud speaker systems; loud speaker arrays; audio receivers; stereo receivers; audio speaker enclosures; loud speaker enclosures; sound recording apparatus; audio recording apparatus; signal processors; audio signal processors; analog signal processors; digital signal processors; metering devices for visual monitoring of audio mixing, amplifying and processing of activities; audio equipment storage racks; audio mixer housings; audio and electronic signal input and output transducers; support stands, equipment racks, mounting brackets and mounting rails, all adapted for use with audio mixers, audio speakers and audio equipment; carrying cases and protective covers specially adapted for electronic equipment, namely, audio equipment; portable audio speakers and audio mixers; digital controllers to automatically control active output combiners, master faders, volume controls; co-axial, computer and electrical cables and wires, integrated circuits and circuit boards; audio speakers in the nature of music studio monitors