Abstract: A headphone system includes a headphone; and a signal processing circuit for outputting an acoustic signal to the headphone. The headphone includes a first speaker and a third speaker for a right ear of a listener, a second speaker and a fourth speaker for a left ear of the listener, and a support for supporting the first through fourth speakers so that the first and second speakers are located forward with respect to a vertical plane including a straight line connecting the hole of the right ear and the hole of the left ear of the listener, the second and fourth speakers are located rearward with respect to the vertical plane, and the first through fourth speakers are out of contact with the right ear and the left ear of the listener.

Abstract: A headphone system includes a headphone; and a signal processing circuit for outputting an acoustic signal to the headphone. The headphone includes a first speaker and a third speaker for a right ear of a listener, a second speaker and a fourth speaker for a left ear of the listener, and a support for supporting the first through fourth speakers so that the first and second speakers are located forward with respect to a vertical plane including a straight line connecting the hole of the right ear and the hole of the left ear of the listener, the second and fourth speakers are located rearward with respect to the vertical plane, and the first through fourth speakers are out of contact with the right ear and the left ear of the listener.

Abstract: A portable playback apparatus includes a manually operated single pushbutton and a control circuit connected to the pushbutton for selectively determining one of a plurality of operating modes of the apparatus in accordance with successive depressions of the pushbutton, or duration of each depression, or in accordance with the number of depressions. The single pushbutton may be attached to an earpiece cord or located on one end face of a housing of the apparatus which is convenient to use.