Radio transmitters and receivers; audio-receivers and video-receivers, sound transmitting apparatus, sound reproduction apparatus, [ cassette and CD players, ] microphones, amplifiers and preamplifiers, Loudspeaker systems, Loudspeakers with built in amplifiers, Public address systems, Public address and sound system accessories, namely, microphones, loudspeakers, microphone cables, speaker cables, and sound mixers; and cables for electrical or optical signal transmission