Acoustic couplers; Cabinets for loudspeakers; Camcorders; Cordless telephones; Headphones; Horns for loudspeakers; Juke boxes, musical; Loudspeakers; Megaphones; Microphones; Mobile telephones; Navigational instruments for vehicles; Notebook computers; Radios; Smartphones; Sound transmitting apparatus; Speaking tubes; Tape recorders; Telephone receivers; Audio equalizer apparatus