Abstract: A control circuit for an electrostatic transducer including: an audio signal input, a detector configured to detect a current or charge signal from the electrostatic transducer. The detector is configured to produce an audio output signal varying at audio frequencies. A transform circuit is configured to transform the audio output signal to produce a feedback signal. A comparator is configured to compare an input audio signal at the audio signal input to the feedback signal to produce an error signal. A controller is configured to input a control signal to the electrostatic transducer, the control signal responsive to the error signal. The control signal is configured to control acoustic transparency of the electrostatic transducer, from outside space through through-holes of the first electrode, across the membrane and through through-holes of the second electrode.

Abstract: Monitoring time-dependent displacement of a membrane in an electrostatic acoustic device. An oscillator is configured to produce a probe signal varying at radio frequency. The probe signal is symmetrically coupled into the first and second electrodes. DC bias voltages are symmetrically applied to the first and second electrodes. A voltage signal from the membrane is sensed and input at a high pass filter input. A multiplier is configured to input the filtered signal modulated at radio frequency and portion of the probe signal. The multiplier is configured to output a multiplied signal which is demodulated to produce therefrom an audio output signal responsive to the time-dependent displacement of the membrane.

Abstract: A processor-based method of reducing loudspeaker-induced harmonic distortion in sound generated by a loudspeaker responsive to a first audio signal, the method including: attenuating a first band in the first audio signal by an attenuation gain, the first band including a fundamental frequency, wherein the attenuating dynamically adjusts the attenuation gain in accordance with, at least, a ratio between: i) an energy of the first band in the first audio signal; and ii) an energy of a second band in the first audio signal, the second band including one or more frequencies that is an integer multiple of the fundamental frequency.

Abstract: Presentation of a recommendation to a user for individual processing of audio tracks in a digital audio workstation. Training audio tracks are provided to a human sound mixer and responsive to the training audio tracks individually processed training audio tracks are received from the human sound mixer. The training audio tracks and the individually processed training audio tracks are input to a machine to train the machine. Audio processing operations are output from the trained machine and stored in a record of a database.

Abstract: A control circuit for an electrostatic transducer including: an audio signal input, a detector configured to detect a current or charge signal from the electrostatic transducer. The detector is configured to produce an audio output signal varying at audio frequencies. A transform circuit is configured to transform the audio output signal to produce a feedback signal. A comparator is configured to compare an input audio signal at the audio signal input to the feedback signal to produce an error signal. A controller is configured to input a control signal to the electrostatic transducer, the control signal responsive to the error signal. The control signal is configured to control acoustic transparency of the electrostatic transducer, from outside space through through-holes of the first electrode, across the membrane and through through-holes of the second electrode.

Abstract: Controlling temperature of a surface of the electronic device. The electronic device includes: a speaker, an adaptive control circuit configured to receive an audio input signal responsive to an audio input power to the speaker and a temperature sensor configured to sense a temperature internal to the electronic device. A temperature signal responsive to the sensed temperature is input to the adaptive control circuit. Responsive to the audio input signal and the temperature signal a power control signal is computed by the adaptive control circuit so that a temperature of the surface of the electronic device at a later time approaches a previously determined target temperature. An audio limiter is configured to limit the audio input power to the speaker responsive to the power control signal.

Abstract: Adjusting gains of an audio mix. Audio tracks using respective gains are individually analyzed to compute a first metric of frequency content. A user input specifies a desired second metric of the frequency content. Responsive to the user input, respective gains of the audio tracks are collectively and simultaneously adjusted to produce respective adjusted gains of the audio tracks. A second audio mix when played of the audio tracks with the respective adjusted gains has a third metric of frequency content different from the first metric of frequency content. The third metric is closer to the second metric than said first metric.

Abstract: A processor-based method of reducing loudspeaker-induced harmonic distortion in sound generated by a loudspeaker responsive to a first audio signal, the method including: attenuating a first band in the first audio signal by an attenuation gain, the first band including a fundamental frequency, wherein the attenuating dynamically adjusts the attenuation gain in accordance with, at least, a ratio between: i) an energy of the first band in the first audio signal; and ii) an energy of a second band in the first audio signal, the second band including one or more frequencies that is an integer multiple of the fundamental frequency.

Abstract: An electrostatic transducer including a membrane, a first electrode and a second electrode. The first electrode is disposed parallel to the membrane. The membrane is configured to respond mechanically to a varying first electric field in accordance with respective electric potentials applied between the first electrode and the membrane. The second electrode is disposed parallel to the membrane opposite from the first electrode. The membrane is configured to respond mechanically to a varying second electric field in accordance with respective electric potentials between the second electrode and the membrane. The first and second electrodes have through holes configured for acoustic transmission to and from the membrane.

Abstract: An acoustic device including a membrane having an edge. A membrane support is attached to the edge of the membrane. A central region of the membrane is unsupported by the support. A first electrode and the membrane support are manufactured as a single element. The first electrode is disposed parallel to the membrane. The membrane is configured to respond acoustically to a varying first electric field emanating from the first electrode when a varying first voltage is applied to the first electrode. A coating is deposited on a surface of the first electrode facing the membrane.

Abstract: Controlling temperature of a surface of the electronic device. The electronic device includes: a speaker, an adaptive control circuit configured to receive an audio input signal responsive to an audio input power to the speaker and a temperature sensor configured to sense a temperature internal to the electronic device. A temperature signal responsive to the sensed temperature is input to the adaptive control circuit. Responsive to the audio input signal and the temperature signal a power control signal is computed by the adaptive control circuit so that a temperature of the surface of the electronic device at a later time approaches a previously determined target temperature. An audio limiter is configured to limit the audio input power to the speaker responsive to the power control signal.

Abstract: Adjusting gains of an audio mix. Audio tracks using respective gains are individually analyzed to compute a first metric of frequency content. A user input specifies a desired second metric of the frequency content. Responsive to the user input, respective gains of the audio tracks are collectively and simultaneously adjusted to produce respective adjusted gains of the audio tracks. A second audio mix when played of the audio tracks with the respective adjusted gains has a third metric of frequency content different from the first metric of frequency content. The third metric is closer to the second metric than said first metric.

Abstract: Presentation of a recommendation to a user for individual processing of audio tracks in a digital audio workstation. Training audio tracks are provided to a human sound mixer and responsive to the training audio tracks individually processed training audio tracks are received from the human sound mixer. The training audio tracks and the individually processed training audio tracks are input to a machine to train the machine. Audio processing operations are output from the trained machine and stored in a record of a database.

Abstract: A membrane hetero-structure includes a polymer layer and a single-layer or multi-layer graphene sheet disposed on the polymer layer. The membrane hetero-structure is tensioned across a frame having an opening such that both the polymer layer and the graphene sheet extend across the opening. An optional rigid member is provided in a center of the membrane to be spaced apart from edges of the opening. The assembly of the frame and membrane hetero-structure forms an electrostatically driven micro-electro-mechanical system (MEMS) or sound generation and recording apparatus. In one instance, when a voltage signal is applied between an electrode layer parallel to the membrane and contacts on the frame that are electrically connected to the graphene sheet, the membrane hetero-structure is actuated.

Abstract: A membrane hetero-structure includes a polymer layer and a single-layer or multi-layer graphene sheet disposed on the polymer layer. The membrane hetero-structure is tensioned across a frame having an opening such that both the polymer layer and the graphene sheet extend across the opening. An optional rigid member is provided in a center of the membrane to be spaced apart from edges of the opening. The assembly of the frame and membrane hetero-structure forms an electrostatically driven micro-electro-mechanical system (MEMS) or sound generation and recording apparatus. In one instance, when a voltage signal is applied between an electrode layer parallel to the membrane and contacts on the frame that are electrically connected to the graphene sheet, the membrane hetero-structure is actuated.