Abstract: A sound producing apparatus with multi-directivity has two or more speakers to produce music or other types of audio sounds. Each of the speakers can produce audio sounds in a certain direction and at least one speaker is steerable so that its sound propagation direction relative to the others can be changed. Furthermore, one or more speakers can produce audio sounds in an adjustable angular range. One or more of the speakers can be dual-mode speakers, each of which can be operated as a wide-angle speaker or a narrow-angle speaker. With multi-directivity, it is possible to play one type of music in one direction and another type of music in another direction to suit the interests of the audience. The apparatus can be a mobile phone, an audio player, a digital or analog recorder/player, or the like.

Abstract: An apparatus uses a transducer to produce vibration in the ultrasonic frequency range and in the audible frequency range. A membrane or cantilever structure is coupled to the transducer to produce acoustic waves. When the vibration is in the audible frequency range, the membrane structure works like a conventional loudspeaker. When the vibration is in the ultrasonic frequency range, the ultrasonic signal is modulated by audio signal for creating better directivity. The acoustic waves in the ultrasonic frequency range can reproduce directional audible sound due to the nonlinear interaction of ultrasonic waves in air.

Abstract: A sound producing apparatus with multi-directivity has two or more speakers to produce music or other types of audio sounds. Each of the speakers can produce audio sounds in a certain direction and at least one speaker is steerable so that its sound propagation direction relative to the others can be changed. Furthermore, one or more speakers can produce audio sounds in an adjustable angular range. One or more of the speakers can be dual-mode speakers, each of which can be operated as a wide-angle speaker or a narrow-angle speaker. With multi-directivity, it is possible to play one type of music in one direction and another type of music in another direction to suit the interests of the audience. The apparatus can be a mobile phone, an audio player, a digital or analog recorder/player, or the like.

Abstract: An apparatus uses a transducer to produce vibration in the ultrasonic frequency range and in the audible frequency range. A membrane or cantilever structure is coupled to the transducer to produce acoustic waves. When the vibration is in the audible frequency range, the membrane structure works like a conventional loudspeaker. When the vibration is in the ultrasonic frequency range, the ultrasonic signal is modulated by audio signal for creating better directivity. The acoustic waves in the ultrasonic frequency range can reproduce directional audible sound due to the nonlinear interaction of ultrasonic waves in air.