A device includes a coil and magnetic mass movable next to the coil in response to vibrations to generate a back electromotive force signal. An amplifier generates, from the back EMF signal, a vibration signal. A processing device converts the vibration signal to time-frequency domain signal as two-dimensional matrix of frequencies mapped against time slots. Pre-process voiced data of the time-frequency domain signal to generate a reduced-noise signal. Average signal values within a frequency window, and that exist at a first time slot, of the reduced-noise signal to generate a complex frequency coefficient. Shift the frequency window across the frequencies to generate multiple complex frequency coefficients that identify speech energy concentration. Replicate signal values at a fundamental frequency within the voiced data to multiple harmonic frequencies to generate an expanded voice source signal. Combine the speech energy concentration with the expanded voice source signal to recreate original speech.

A method, system and devices to selectively control modal vibrations in an elastic panel with a number of force actuators distributed throughout the surface of the elastic panel to excite/depress the response of one or more vibrational resonant modes included in a prescribed subset. The force actuators are disposed such that prescribed modal excitation/depression may be realized when the actuators are driven by a common source signal.

A loudspeaker system with viscoelastic material affixed between two flexible panels is disclosed. The loudspeaker system dissipates the energy of motion, resulting in less pronounced resonant peaks. The effect may be especially evident at high frequencies, where energy is dissipated over many cycles in a shorter period of time. Also disclosed are the method of making the loudspeaker system and a method of using the loudspeaker system.

Provided are a pickup sensor and a biological sensor that are small-sized and can detect micro vibration efficiently and stably with high accuracy. The pickup sensor includes an electroacoustic converter film including: a piezoelectric polymer composite in which piezoelectric particles are dispersed in a viscoelastic matrix that is formed of a polymer material having viscoelasticity at normal temperature; two thin film electrodes that are laminated on opposite surfaces of the piezoelectric polymer composite, respectively; and a protective layer that is laminated on at least one of the two thin film electrodes, in which at least a part of a surface of the electroacoustic converter film is an abutting surface that abuts against a test object, and the thin film electrode on a surface opposite to the abutting surface is grounded.

Examples are disclosed herein that relate to avoiding mechanical noise from operation of a vibrational output device. One example provides a computing device including a processor and a storage device storing instructions executable by the processor to vary a drive voltage applied to a vibrational output device, receive acoustic data, and from the acoustic data detect a noise signal from the vibrational output device as the drive voltage is varied. The instructions are further executable to, based upon the detected noise signal, select an operational drive voltage for the vibrational output device, and operate the vibrational output device using the operational drive voltage.

This application describes an apparatus (300) for monitoring for blockage of an acoustic (110) port of a microphone device (100). The apparatus has a spectrum peak detect block (301) for receiving a microphone signal (S.sub.MIC) and determining, from the microphone signal, a resonance frequency (f.sub.H) and a quality factor (Q.sub.H) of a resonance (202) associated with the acoustic port. A condition monitoring block (302) is configured to determine any change in resonance frequency and quality factor and to determine a blockage status for the microphone based on said detect changes. The condition monitoring block identifies a change in blockage status if there is a change in quality factor.

A microphone transducer is provided, the microphone transducer comprising a housing and a transducer assembly supported within the housing and defining an internal acoustic space. The transducer assembly includes a magnet assembly, a diaphragm disposed adjacent the magnet assembly and having a front surface and a rear surface, and a coil attached to the rear surface of the diaphragm and capable of moving relative to the magnet assembly in response to acoustic waves impinging on the front surface. The transducer assembly further includes a primary port establishing acoustic communication between the internal acoustic space and an external cavity at least partially within the housing, and a secondary port located at the front surface of the diaphragm.

Disclosed is a display apparatus capable of improving a sound quality through an accurate sound transmission, wherein the display apparatus may include a backlight module connected with a rear surface of a display panel, a rear structure for surrounding the backlight module, and a vibration generating device for vibrating the display panel through the backlight module, wherein the vibration generating device is fixed to the rear structure.

An audio system for a vehicle is provided with a woofer speaker having a front side for producing a required bass-range acoustic output in a passenger compartment of the vehicle and a back side having an infinite baffle. The audio system includes a bass-compatible speaker disposed in the passenger compartment of the vehicle. A controller is in communication with the woofer and the bass-compatible speaker and is programmed to distribute the required bass-range sound output to the woofer and the bass-compatible speaker based on at least one of a vehicle speed and a sound output level of the audio system.

A camera includes one or more microphone pairs. A first microphone (e.g., a main microphone) is ported to the outside of the camera and captures the desired external audio signal, but may also capture undesired vibrational noise. A second microphone has a similar structure to the first microphone, but is not ported to the outside of the camera. Instead, the second microphone is ported into an enclosed cavity (e.g., 1-2 cubic centimeters in volume). The second microphone may pick up the same vibration excitation and internal acoustic noise as the first microphone but very little of the desired external acoustic sounds around the camera. The unwanted noise can then be removed by subtracting the second audio signal from the second microphone from the main audio signal from the main microphone.