Sound recording apparatus; sound transmitting apparatus; sound reproduction apparatus; apparatus for processing sound; audio mixing apparatus; video recorders; camcorders; electric and electronic effects units for musical instruments; digital sound processors; analogue sound modifiers; audio interfaces; audio and video receivers; equalizers being audio apparatus; data processing apparatus; transponders; megaphones; loudspeakers; monitoring apparatus, other than for medical purposes; monitoring instruments; headphones; sound amplifiers; amplifiers for musical instruments; audio mixers; audio mixing consoles; stage lighting regulators; microphones; acoustic couplers.