Electroacoustic drivers that can be utilized in loudspeaker systems that utilize bidirectional force electromagnet transducers or piezoelectric transducers. The electroacoustic drivers can include motion amplifiers such as lever arms. The electroacoustic drivers can be used at all audio frequencies including frequencies below 500 Hz.

A holographic-based directional sound device is provided, the device including: a sound wave generating means generating a sound wave; and a flat plate configured to have the sound wave generating means installed at the center so as to radiate the sound wave to the outside through a surface, and to be composed of a plurality of unit cells, in which at least one groove is formed on a surface of the unit cell, and a radiation angle of the sound wave is determined according to a depth of the groove with respect to the unit cell, wherein the depth of the groove is determined by an individual surface admittance calculated by a cosine function or a sine function of the sum of a first value and a second value on the basis of a preset radiation angle of the sound wave and a preset frequency of the sound wave.

Embodiments provide an apparatus for sound conversion, wherein the apparatus includes a sound channel and a sound transducer coupled to the sound channel, wherein the apparatus comprises an acoustic low-pass filter arranged in the sound channel.

An apparatus may include a vibration member, a supporting member at a rear surface of the vibration member, and a vibration apparatus. The vibration apparatus may be disposed at the supporting member and may include a curved shape.

An apparatus may include a vibration member, a rear cover at a rear surface of the vibration member, a first vibration device at a first rear region of the rear cover, and a second vibration device at a second rear region of the rear cover. The first vibration device may overlap at least one of a horizontal region and a middle region of the rear cover. The second vibration device may overlap a periphery region or a middle region of the rear cover.

Techniques are provided for generating sound using a speaker mounted to an enclosure (e.g., speaker cabinet) wherein a gas pressure level (e.g., air pressure level) inside the enclosure is lower than an ambient air pressure level outside the enclosure. The reduced gas pressure level within the enclosure provides an environment with a reduced pressure level at a back side of a speaker cone of the speaker, which enhances a low frequency response for a given speaker size, while also minimizing resonant frequencies and phase cancellation issues which could otherwise occur with conventional speaker systems in which acoustic sound waves are generated at the back side of the speaker cone. A pressure compensation system is utilized counteract a force applied to the front side of the speaker cone as a result of the gas pressure level inside the enclosure being lower than the ambient air pressure level outside the enclosure.

The present disclosure relates to an acoustic output device including an earphone core, a controller, a Bluetooth module, and a button module. The earphone core may include at least one low-frequency acoustic driver configured to output sounds from at least two first guiding holes and at least one high-frequency acoustic driver configured to output sounds from at least two second guiding holes. The controller may be configured to direct the at least one low-frequency acoustic driver to output the sounds in a first frequency range and direct the at least one high-frequency acoustic driver to output the sounds in a second frequency range. The Bluetooth module may be configured to connect the acoustic output device with at least one terminal device. The button module may be configured to implement an interaction between a user of the acoustic output device and the acoustic output device.

An acoustic device comprises a shell and a sound producing assembly, the shell being provided with an installation hole and a sound outlet, and the sound producing assembly being fixed inside the shell. The sound producing assembly has a diaphragm separating a cavity of the acoustic device into a front cavity and a back cavity, a first part of the shell corresponding to the front cavity and/or a second part of the shell corresponding to the back cavity is provided with sapphire glass covering the installation hole, and the front cavity is in communication with the outside of the acoustic device through the sound outlet.

A headphone includes a speaker unit, a baffle plate, an ear pad, and a grille. The baffle plate is configured to support the speaker unit. The ear pad is configured to surround an acoustic space in which a sound emitted from the speaker unit is transmitted toward an ear of a listener. The grille is configured to cover the speaker unit. The grille has a hole and a cavity connected to the hole.

A vehicle and a controlling method of the same include a speaker outputting virtual engine sound integrated with a head lamp. The vehicle includes the head lamp; a head lamp case in which the head lamp is provided; and a speaker for outputting a virtual engine sound, and provided inside the head lamp case, where an internal cross-sectional area of the head lamp case may increase in a direction toward a front of the vehicle based on a position where the speaker is provided.