Abstract: An electromechanical and electroacoustic transducer is compact and has a simple drive circuit. Two independent magnetic circuits share a single permanent magnet. A voice coil is placed in one of the magnetic circuits, and a magnetic weight is placed in the other magnetic circuit. A switching element is turned on and off upon movements of the magnetic weight.

Abstract: There is provided an audio output apparatus capable of providing an effect, with a limited number of speakers, as if the person displayed on the display screen is really speaking. When the television conference is started with a communication partner through a set top box, the image of the communication partner is displayed on the image displaying reflective plate. At the same time, ultrasonic waves superposed with the voice of the partner are emitted from a left speaker and a right speaker. The sound emitting directions of the left and right speakers are directed toward the image displaying reflective plate on which the partner is displayed. The ultrasonic waves emitted from the left and right speakers are reflected by the reflective plate and proceed toward the listener who can hear the voice of the partner as if the voice is directly emitted from the reflective plate.

Abstract: A stereo sound expander reproduces a realistic sound image in three dimensions by coupling modified and unmodified stereo signals. By not modifying a Head Related Transfer Function (HRTF) for one signal and equalizing the HRTF for the other signal, a flattened frequency response is produced with no tonal changes, but with a high degree of spatial accuracy. Resultant output signals may be used to generate binaural signals or can be fed into crosstalk cancellers.