The present invention provides an electret sheet that exhibits excellent piezoelectricity even by light stress. The electret sheet of the invention is characterized by including a charged porous sheet, in which the electret sheet has a compressive elastic modulus of 80 to 300 MPa when compressively deformed at 25° C. and a 50% compression stress of 120 to 300 kPa at 25° C., and thus has the excellent piezoelectricity for light stress and exhibits the excellent piezoelectricity even by light stress (0.5N or less) caused by a pulse wave or a breathing.

The present application discloses an apparatus for controlling an earphone and a media player in communication with the earphone, including an ambient sound detector configured to detect an ambient sound volume level; a processor configured to select an adjustment value to be applied to an audio volume level to be produced by an earphone speaker of the earphone based on the ambient sound volume level; and a controller configured to adjust the audio volume level of the earphone speaker based on the adjustment value selected by the processor.

The present application discloses an apparatus for controlling an earphone and a media player in communication with the earphone, including an ambient sound detector configured to detect an ambient sound volume level; a processor configured to select an adjustment value to be applied to an audio volume level to be produced by an earphone speaker of the earphone based on the ambient sound volume level; and a controller configured to adjust the audio volume level of the earphone speaker based on the adjustment value selected by the processor.

Provided is an acoustic transducer including: a semiconductor substrate; a vibrating membrane provided above the semiconductor substrate, including a vibrating electrode; and a fixed membrane provided above the semiconductor substrate, including a fixed electrode, the acoustic transducer detecting a sound wave according to changes in capacitances between the vibrating electrode and the fixed electrode, converting the sound wave into electrical signals, and outputting the electrical signals. At least one of the vibrating electrode and the fixed electrode is divided into a plurality of divided electrodes, and the plurality of divided electrodes outputting the electrical signals.

Measures for regulating the electrical bias voltage at the measuring capacitor of a MEMS sensor element are described. A base voltage is applied to the measuring capacitor and regulated in such a way that the potential difference between the two electrode sides of the measuring capacitor corresponds to the setpoint voltage. The base voltage is regulated in a low-voltage range.

Offset cartridge microphones are provided that include multiple unidirectional microphone cartridges mounted in an offset geometry. Various desired polar patterns and/or desired steering angles can be formed by processing the audio signals from the multiple cartridges, including a toroidal polar pattern. The offset geometry of the cartridges may include mounting the cartridges so that they are immediately adjacent to one another and so that their center axes are offset from one another. The microphones may have a more consistent on-axis frequency response and may more uniformly form desired polar patterns and/or desired steering angles by reducing the interference and reflections within and between the cartridges.

In some embodiments, a microphone system may include a deformable element that may be made of a material that is subject to deformation in response to external phenomenon. Sensing ports may be in contact with a respective region of the deformable element and may be configured to sense a deformation of a region of the deformable element and generate a signal in response thereto. The plurality of signals may be useable to determine spatial dependencies of the external phenomenon. The external phenomenon may be pressure and the signals may be useable to determine spatial dependencies of the pressure.

An analog signal is received from an acoustic transducer. The analog signal is converted into digital data. A determination is made as to whether acoustic activity exists within the digital data. The digital data is stored in a temporary memory storage device and a count is maintained of an amount of digital data in the temporary memory storage device. When the count exceeds a predetermined threshold, at least some of the digital data is transmitted from the temporary memory storage device to a processor.

An analog signal is received from an acoustic transducer. The analog signal is converted into digital data. A determination is made as to whether acoustic activity exists within the digital data. The digital data is stored in a temporary memory storage device and a count is maintained of an amount of digital data in the temporary memory storage device. When the count exceeds a predetermined threshold, at least some of the digital data is transmitted from the temporary memory storage device to a processor.

In one embodiment of an audio system, a transducer can be coupled to a passive acoustic directional amplifier to provide various benefits and improvements, including improvements to: speech intelligibility, signal-to-noise ratio, effective equivalent input noise, at-a-distance acoustic signal reception, and directional preference. In another embodiment, the shape of an interior surface of a passive acoustic directional amplifier is provided. In another embodiment, the material properties of an interior surface of a passive acoustic directional amplifier are provided.