A dynamic acoustic impedance matching device for an acoustic signal transmitted or received in a medium by a transducer includes a particle flow in an acoustic signal path of the transducer. The particle flow has an acoustic impedance between an acoustic impedance of the transducer and an acoustic impedance of the medium.

An apparatus for use with an electronic device having a microphone. The apparatus comprises a structure configured to detachably couple to the device, and a generator supported by the structure. The generator is configured to generate a force that acts on the microphone and renders the microphone unresponsive to voice sounds.

Disclosed herein are methods and apparatuses for the transmission of audio information from a bone-conduction headset to a user. The bone-conduction headset may be mounted on a glasses-style support structure. The bone-conduction transducer may be mounted near where the glasses-style support structure approach a wearer's ears. In one embodiment, an apparatus has a bone-conduction transducer with a diaphragm configured to vibrate based on a magnetic field. The magnetic field being based off an applied electric field. The apparatus may also have an anvil coupled to the diaphragm. The anvil may be configured to conduct the vibration from the bone-conduction transducer. Additionally, the anvil may be coupled to a metallic component. The metallic component may be configured to couple to a magnetic field created by the bone-conduction transducer.

Disclosed herein are methods and apparatuses for the transmission of audio information from a bone-conduction headset to a user. The bone-conduction headset may be mounted on a glasses-style support structure. The bone-conduction transducer may be mounted near where the glasses-style support structure approach a wearer's ears. In one embodiment, an apparatus has a bone-conduction transducer with a diaphragm configured to vibrate based on a magnetic field. The magnetic field being based off an applied electric field. The apparatus may also have an anvil coupled to the diaphragm. The anvil may be configured to conduct the vibration from the bone-conduction transducer. Additionally, the anvil may be coupled to a metallic component. The metallic component may be configured to couple to a magnetic field created by the bone-conduction transducer.

An integrated audible sound output system incorporated in a personal media device is described. The integrated audible sound output system includes a first audio output port, the first audio output port acoustically coupled with the audible sound generator unit by way of a first air path and a second audio output port. In the described embodiments, the second audio output port is acoustically coupled with the audible sound generator unit by way of a second air path. The first and the second air paths cooperate to pass the audible sound generated by the audible sound generator unit to the external environment by way of the first audio port and the second audio port.

An electromechanical transducer of the invention comprises a structural unit, an armature, and two elastic units. The structural unit includes magnets, a yoke and a coil. The armature has an inner portion disposed to pass through inside the structural unit and two outer portions protruding from the inner portion, and the armature constitutes a magnetic circuit with the structural unit via two regions through which components of the magnetic flux flow in reverse directions in the inner region. The elastic units give restoring forces to the outer portions in response to displacement of the armature due to magnetic forces of the magnetic circuit. Each of the elastic units includes a pair of elastic members symmetrically arranged via the armature in a direction of the displacement. Each of the elastic members has one end engaging one of the outer portions and another end engaging one of the elastic member attaching portions.

According to the present invention, air conduction sound and human body vibration sound (e.g. bone conduction sound) are transmitted to a user without a need for pressing a vibration body itself to an ear. An electronic device 1 of the present invention includes: a panel 10; a housing 60 configured to support the panel 10; and a piezoelectric element 30 attached to the panel 10. The panel 10 is deformed due to deformation of the piezoelectric element 30, and air conduction sound and human body vibration sound are transmitted to an object that is in contact with the deformed panel 10.

Systems and method are provided herein for balancing of outputs from playback devices playing audio content in synchrony. In one embodiment, the balancing of outputs may involve receiving a first audio signal to be played by a first playback device according to a first crossover frequency, determining a limiting result by applying a limiting function associated with a second playback device to a second audio signal to be played by the second playback device according to a second crossover frequency, and based on the first limiting result, configuring the first playback device to play the first audio signal according to a third crossover frequency. In some cases, the first and second playback devices may be configured to play the first and second audio signals, respectively, in synchrony.

Systems and methods are provided herein for balancing of outputs from playback devices playing audio content in synchrony. In one embodiment, the balancing of outputs may involve receiving a first audio signal to be played by a first playback device, determining a first limiting result by applying to a second audio signal a limiting function associated with a second playback device, determining a limiting function based on the first limiting result, and configuring the first playback device to apply the determined limiting function when playing the first audio signal. In some cases, the first and second playback devices may be configured to play the first and second audio signals, respectively, in synchrony.

An example implementation involves a first playback device receiving audio content to be played back by the first playback device and a second playback device in synchrony. Such audio content may include a first and second stereo component. The first playback device determines a limiting result that indicates frequencies at which a playback volume of the second playback device is limited and determines a crossover frequency based on the indicated frequencies at which the playback volume of the second playback device is limited. The first playback device causes the second playback device to play a first portion of the second stereo component that is above the determined crossover frequency and plays (i) the first stereo component and (ii) a second portion of the second stereo component that is below the indicated frequency in synchrony with playback of the first portion by the second playback device.