An apparatus includes a vibration member and a first cover disposed at a rear surface of the vibration member. The apparatus also includes a first vibration apparatus disposed at a rear surface of the first cover and configured to vibrate the vibration member. The apparatus includes a first enclosure member disposed at the rear surface of the first cover and at the rear surface of the vibration member. The apparatus also includes a first rear vibration member disposed at the first enclosure member.

An apparatus includes a vibration member and a first cover disposed at a rear surface of the vibration member. The apparatus also includes a first vibration apparatus disposed at a rear surface of the first cover and configured to vibrate the vibration member. The apparatus includes a first enclosure member disposed at the rear surface of the first cover and at the rear surface of the vibration member. The apparatus also includes a first rear vibration member disposed at the first enclosure member.

A speaker comprises a housing, a transducer residing inside the housing, and at least one sound guiding hole located on the housing. The transducer generates vibrations. The vibrations produce a sound wave inside the housing and cause a leaked sound wave spreading outside the housing from a portion of the housing. The at least one sound guiding hole guides the sound wave inside the housing through the at least one sound guiding hole to an outside of the housing. The guided sound wave interferes with the leaked sound wave in a target region. The interference at a specific frequency relates to a distance between the at least one sound guiding hole and the portion of the housing.

An acoustic transducer (30), comprising: a support structure (36); an active assembly comprising a base plate (32) supported by the support structure (36) and a piezoelectric body (34) supported by the base plate (32); and a passive vibrator (38) supported by the support structure (36) and coupled via the support structure (36) to the active assembly (32, 34) so that vibration of the active assembly (32, 34) drives the passive vibrator (38). The active assembly (32, 34) and the passive vibrator (38) have the same resonant frequency.

An acoustic transducer (30), comprising: a support structure (36); an active assembly comprising a base plate (32) supported by the support structure (36) and a piezoelectric body (34) supported by the base plate (32); and a passive vibrator (38) supported by the support structure (36) and coupled via the support structure (36) to the active assembly (32, 34) so that vibration of the active assembly (32, 34) drives the passive vibrator (38). The active assembly (32, 34) and the passive vibrator (38) have the same resonant frequency.

An acoustic wave device includes a substrate, functional elements on a first main surface of the substrate, an outer support portion on the substrate around a region where the functional elements are disposed, a cover portion opposed to the first main surface of the substrate with the outer support portion interposed therebetween, a support portion in a hollow space defined by the substrate, the outer support portion, and the cover portion, a wiring pattern electrically connected to the functional elements, and a through electrode extending through the substrate and electrically connected to the wiring pattern. A gap is provided between the support portion and the cover portion. A distance from the first main surface of the substrate to an upper surface of the support portion is greater than a distance from the first main surface of the substrate to an upper surface of the functional elements.

An acoustic wave device includes a substrate, functional elements on a first main surface of the substrate, an outer support portion on the substrate around a region where the functional elements are disposed, a cover portion opposed to the first main surface of the substrate with the outer support portion interposed therebetween, a support portion in a hollow space defined by the substrate, the outer support portion, and the cover portion, a wiring pattern electrically connected to the functional elements, and a through electrode extending through the substrate and electrically connected to the wiring pattern. A gap is provided between the support portion and the cover portion. A distance from the first main surface of the substrate to an upper surface of the support portion is greater than a distance from the first main surface of the substrate to an upper surface of the functional elements.

An ultrasonic transducer includes a transducer case and an ultrasonic element. The transducer case is formed into a bottomed, cylindrical shape having a side plate portion and a bottom plate portion that seals one end side of the side plate portion in an axial direction to configure a diaphragm. The ultrasonic element is fixedly supported to the bottom plate portion to face an interior space surrounded by the side plate portion and the bottom plate portion. The ultrasonic element is arranged in a position being offset in an in-plane direction orthogonal to the axial direction relative to a center position of the diaphragm in the in-plane direction to be capable of generating a first transmission wave having first directivity characteristics and a second transmission wave having second directivity characteristics that are directivity characteristics differing from the first directivity characteristics and in which sound pressure in the axial direction is decreased.

An MEMS device includes a substrate with a substrate plane, a mass element having a rest position and configured to perform a deflection from the rest position parallel to the substrate plane and in a fluid surrounding the mass element. Further, the MEMS device includes a spring arrangement that is coupled between the substrate and the mass element and configured to deform based on the deflection. An actuator structure is provided that is coupled to the mass element by means of a coupling and configured to apply a force to the mass element by means of the coupling to cause the deflection and a movement of the fluid.

Electroacoustic drivers that can be utilized in loudspeaker systems that utilize drivers having a magnetic negative spring (MNS) (such as reluctance assist drivers (RAD) and permanent magnet crown (PMC) drivers). The electroacoustic drivers can be used at all audio frequencies, including subwoofer frequencies. The magnetic negative springs of the electroacoustic drivers can cancel, or partially cancel, the large pressure forces on a sound panel (of an audio speaker) so that substantial subwoofer notes can be efficiently and cost effectively produced in small/portable speakers. The electroacoustic drivers can include a stabilizing/centering mechanism to overcome the destabilizing forces of a MNS that are too large for a voice coil alone to produce.