A speaker control device in one embodiment includes an oscillator connected in parallel with a drive circuit for driving a speaker, the oscillator changing an oscillation frequency according to a voltage, and a control circuit detecting a variation in the oscillation frequency of the oscillator, and adjusting an amount of current supplied to the speaker by the drive circuit in the case where a variation in the voltage exceeds an allowable value.

Provided is an electro-acoustic conversion film that is suitably used for a digital speaker or the like, and that includes a polymer composite piezoelectric body formed by dispersing piezoelectric particles in a viscoelastic matrix formed of a polymer material having viscoelasticity at room temperature, and thin-film electrodes provided on both surfaces of the polymer composite piezoelectric body, and at least one of the thin-film electrodes is divided into a plurality of regions of which an area increases by 2.sup.n times (n is a natural number including 0). Thus, a digital speaker in which reverberation or crosstalk between segments is suppressed is obtained.

A digitally driven headphone suppresses the occurrence of spurious radiation even when directly converting digital signals into sound waves. The digitally driven headphone includes a first sound emission unit, a second sound emission unit, and a signal line. The first sound emission unit includes at least one magnetic body into which the signal line is inserted, a signal processing circuit configured to process digital signals from a sound source, a circuit board on which the signal processing circuit is disposed, a driving part configured to drive the diaphragm in response to digital signals from the sound source, and a diaphragm configured to vibrate in response to driving of the driving part. The signal processing circuit has an output part disposed at an end portion of the circuit board. The signal line is inserted into the at least one magnetic body, and is connected to the output part and the second sound emission unit. The at least one magnetic body is disposed adjacent to the output part.

The present invention discloses an implementation method and a device of a multi-bit - modulation-based digital speaker system. The method comprises, 1) digital format converting; 2) oversampling interpolation filtering; 3) multi-bit - modulating; 4) thermometer coding; 5) multi-channel mismatch shaping; 6) coding format converting; 7) multi-channel digital power-amplifying; 8) driving a speaker array or a multiple voice coil speaker to sound. The device comprises: a digital input interface, an oversampling interpolation filter, a multi-bit - modulator, a thermometer coder, a multi-channel mismatch shaper, a coding format converter, a multi-channel digital power-amplifier, and a speaker array or a multiple voice coil speaker; each portion being connected in proper order. The present invention can achieve a high-power output under a low-voltage power supply, save power consumption, implement a single-chip integration of a multi-channel reproducing system, reduce the volume and weight of the system and the implementing cost, and improve the quality of the reproduced sound.

Various examples are provided for digital sound reconstruction using piezoelectric array elements. In one example, a digital loudspeaker includes a fixed frame and an array of transducers disposed on the fixed frame. Individual transducers of the array of transducers can include a flexible membrane disposed on a piezoelectric actuation element positioned over a corresponding opening that extends through the fixed frame. In another example, a method includes forming a flexible membrane structure on a substrate and backetching the substrate opposite the flexible membrane structure. The flexible membrane structure can be formed by disposing a first electrode layer on a substrate, disposing a piezoelectric layer on the first electrode layer and disposing a second electrode layer on the piezoelectric layer. A flexible membrane layer (e.g., polyimide) can be disposed on the second electrode layer.

A digital acoustic device including: at least one suspended diaphragm facing a support and at least one actuator associated with the diaphragm, the associated actuator being configured to move the diaphragm away from and/or closer to the support; a stop mechanism configured to interrupt movement of the diaphragm further to activating the actuator when the diaphragm has a non-zero speed, the stop mechanism being sized to interrupt the movement of the diaphragm when the movement of the diaphragm is greater than or equal to 50% of the theoretical maximum stroke of the diaphragm and lower than or equal to 95% of the theoretical maximum stroke of the diaphragm.

A device has a standard female audio connector that is capable of receiving four-pole male connectors and three-pole male connectors and implements: means (CTRL, VCC, S1) for selectively transmitting a DC power supply signal via a first pin (DP1) of said connector; means (CTRL, ANC) for selectively activating a cancellation mechanism for ambient noise from digital audio signals that are intended to be received, via the first pin, in a manner superimposed on said DC power supply signal; means (CTRL, MIF) for selectively transmitting via a second pin of said connector, in a manner superimposed on said audio signals, a timing clock that is intended for digital microphones (DML, DMR) or other sensors; means (CTRL) for configuring itself vis--vis the DC power supply signal, the ambient noise cancellation mechanism and the timing clock, according to a determined type of listening device that is effectively connected via said connector.

A system which controls a group of multiple arrays of actuator elements, each of the actuator elements including a moving element which moves between a first and a second extreme positions; the system including: a controller, configured to generate control commands for at least one array of the multiple arrays in each individual cycle out of a series of sampling cycles, based on obtained information; and (b) an interface configured to transfer the control commands to the at least one array, thereby resulting in releasing from the first extreme position during the intended cycle of at least one moving element that is included in the at least one array; wherein release of all moving elements of at least one restrained array out of the multiple arrays is prevented during the intended cycle.

A wiring structure is provided for an electroacoustic transducer directly converting digital signals from a single sound source to sound waves without conversion to analog signals. The structure includes a diaphragm, and a plurality of voice coils fixed to the diaphragm. The voice coils are connected to respective cables each consisting of a stranded pair of positive and negative input lines.

This application relates to methods and apparatus for switching drivers. The switching driver has first and second switches for selectively connecting an output node to first and second switching voltages respectively to generate a first output voltage. A compensator is configured to receive a first monitor signal indicative of a sum of the first and second switching voltages and a second monitor signal indicative of a difference between the first and second switching voltages and to apply compensation to the input signal based on the first and second monitor signals so as to compensate for variations in the first and second switching voltages from defined nominal values of the first and second switching voltages. A modulator controls a duty cycle of the first and second switches based on the input signal after said compensation has been applied.