Abstract: A speaker system that includes an audio signal-receiving interface, a modulating circuit, a phase-control circuit, and a number of speaker units. The audio signal-receiving interface is configured to receive an audio signal, and the modulating circuit is coupled with the audio signal-receiving interface. The modulating circuit is configured to modulate a low frequency component of the audio signal and to generate a modulated signal. The phase-control circuit is coupled with the modulating circuit and the audio signal-receiving interface. The phase-control circuit is configured to receive the modulated signal and a high-frequency component of the audio signal and to control a phase of the modulated signal, a phase of the high-frequency component of the audio signal, or both. The speaker units are coupled with the phase-control circuit and configured to generate sound waves based on signals supplied by the phase-control circuit.

Abstract: An ultrasound transducer has a cup-shaped casing. The cup-shaped casing has a sidewall. A cross section of an inner surface of the sidewall being perpendicular to a central axis of the ultrasound transducer substantially shows a dumbbell-shaped contour. The dumbbell-shaped contour has a pair of opposite straight-line sections being substantially parallel to a longitudinal axis of the dumbbell-shaped contour and a pair of opposite arc sections being located respectively at two ends of the longitudinal axis of the dumbbell-shaped contour and respectively forming two enlarged portions of the dumbbell-shaped contour. Two ends of each arc section of the dumbbell-shaped contour respectively joint the straight-line sections through two curve sections and each curve section is connected to one end of the arc section and one straight-line section. At least one enlarged area of a dumbbell-shaped surface of an inside bottom surface has a recessed portion.

Abstract: An ultrasound transducer has a cup-shaped casing. The cup-shaped casing has a sidewall. A cross section of an inner surface of the sidewall being perpendicular to a central axis of the ultrasound transducer substantially shows a dumbbell-shaped contour. The dumbbell-shaped contour has a pair of opposite straight-line sections being substantially parallel to a longitudinal axis of the dumbbell-shaped contour and a pair of opposite arc sections being located respectively at two ends of the longitudinal axis of the dumbbell-shaped contour and respectively forming two enlarged portions of the dumbbell-shaped contour. Two ends of each arc section of the dumbbell-shaped contour respectively joint the straight-line sections through two curve sections and each curve section is connected to one end of the arc section and one straight-line section. At least one enlarged area of a dumbbell-shaped surface of an inside bottom surface has a recessed portion.

Abstract: A speaker system that includes an audio signal-receiving interface, a modulating circuit, a phase-control circuit, and a number of speaker units. The audio signal-receiving interface is configured to receive an audio signal, and the modulating circuit is coupled with the audio signal-receiving interface. The modulating circuit is configured to modulate a low frequency component of the audio signal and to generate a modulated signal. The phase-control circuit is coupled with the modulating circuit and the audio signal-receiving interface. The phase-control circuit is configured to receive the modulated signal and a high-frequency component of the audio signal and to control a phase of the modulated signal, a phase of the high-frequency component of the audio signal, or both. The speaker units are coupled with the phase-control circuit and configured to generate sound waves based on signals supplied by the phase-control circuit.