Sound-recording apparatus, apparatus for transferring and reproducing of sound or images, including magnetic tape recorders, dictating machines, video tape recorders, video record players, record players, players of magnetic tapes, laser record players, radio sets, radio-tape recorders, magnetic radiogramophones; musical systems, including block of amplifiers, tuners, tape decks, electrical record players, equalizers, speakers; amplifiers, audio-frequency amplifiers, loudspeakers (acoustic radiators, tweeters, midrange speakers and squawkers), heads for loudspeakers, boxes for loudspeakers, horns for loudspeakers, tone arms for record players, pick-ups