A parametric equalizer includes an equalizer circuit, a first protection circuit, a second protection circuit, and a first addition circuit. The equalizer circuit is arranged to receive an input signal, and process the input signal to generate an output signal. The first protection circuit is arranged to generate a first protection signal according to the output signal, the input signal, and a first processed signal. The second protection circuit is arranged to generate a second protection signal according to the input signal and a second processed signal. The first addition circuit is coupled to the first protection circuit and the second protection circuit, and is arranged to combine the first protection signal and the second protection signal to generate an equalizer output signal.

A microphone includes an amplifier coupled to an input node of the microphone; a shock detector coupled to the input node of the microphone; and a recovery circuit having an input coupled to an output of the shock detector, and an output coupled to the input of the microphone.

Example embodiments provide a process that includes one or more of receiving an audio signal at a feedback compressor circuit, receiving an auxiliary attenuation signal from an auxiliary attenuation source, determining a threshold power level based on a value of the auxiliary attenuation signal, determining an output power level of the audio signal exceeds the threshold power level, combining the audio signal with the auxiliary attenuation signal from the auxiliary attenuation source and a compressed attenuation signal from the feedback compressor circuit to create a combination signal, and generating an audio output signal of the feedback compressor circuit based on the combination signal.

Disclosed is a method for increasing a perceived loudness of an audio data signal comprising the steps of obtaining a first digital audio data signal; determining at least one temporal amplitude peak in the first digital audio data signal; generating a second digital audio data signal by reducing the at least one temporal amplitude peak in the first digital audio data signal based on a predicted perceptual difference model representing a predicted perceptual difference between the first digital audio data signal and a peak reduced version of the first digital audio data signal; and generating a third digital audio data signal by amplifying the second digital audio data signal so that a peak of the second digital audio data signal has a predetermined signal value, wherein a perceived loudness of the third digital audio data signal is larger than a perceived loudness of the first digital audio data signal.

A panel audio loudspeaker includes a panel and an actuator attached to a surface of the panel and configured to cause vibration of the panel. The actuator comprises a magnetic coil in thermal communication with the panel. The panel audio loudspeaker further comprises a plurality of electrical sensors electrically coupled to the magnetic coil and configured to output time-varying electrical data for the magnetic coil, and an electronic control module in communication with the magnetic coil and the electrical sensors. The electronic control module is configured to perform operations comprising: providing a current to the magnetic coil; receiving the time-varying electrical data for the magnetic coil; determining an electrical energy provided to the magnetic coil between a first time and a second time; accessing a thermal model of the panel; and determining a change in a panel temperature between the first time and the second time.

A system for improvement of waveform transmission and event detection includes a first transducer configured to receive acoustic waveforms, and a first transducer processor and transmitter configured to invert the phase of the received waveforms of the first transducer and transmit the inverted waveforms via light to a second transducer. The second transducer is configured to receive light waveforms from the first transducer processor and transmitter, receive acoustic waveforms from the second transducer, convert the first transducer light waveforms and the second transducer acoustic waveforms into electrical waveforms, and transmit a combined electrical waveform onwards.

A system for determining the temperature of a voice coil of a speaker includes a first pre-emphasis filter which has an input coupled to receive a digitized current sense signal. The first pre-emphasis filter applies a gain to signal components at a selected frequency band and provides a pre-emphasized current sense signal. The system includes a second pre-emphasis filter which has an input coupled to receive a digitized voltage sense signal. The second pre-emphasis filter applies a gain to the signal components at the selected frequency band and provides a pre-emphasized voltage sense signal. The system includes a first quantizer module configured to map the pre-emphasized signal to a quantized current sense signal, and includes a second quantizer module configured to map the pre-emphasized voltage sense signal to a quantized voltage sense signal.

This application relates to audio driving circuitry (100), and in particular to audio driving circuitry for outputting first and second audio driving signals for driving a stereo audio load (106), which may be a stereo audio load of an accessory apparatus (102) removably coupled to the audio driving circuitry in use. A load monitor (111) is provided for monitoring to monitor, from a monitoring node (112), an indication of a common mode return current passing through a common return path, together with an indication of a common mode component of the first and second audio driving signals and to determine an impedance characteristic of the stereo audio load. The load monitor (111) can provide dynamic monitoring of any significant change in load impedance. In some embodiments the load monitor (111) comprises an adaptive filter (301) which adapts a parameter of the filter which is related to the load impedance so as to determine the indication of load impedance.

The present disclosure provides a limiter system. The limiter system includes a first equalization filter, a low-pass filter, a first limiter, a high-pass filter, a second limiter, and a mixer. The limiter system provided by the present disclosure further includes a second equalization filter. An audio signal from a signal source first passes through the first equalization filter, the signal equalized for the first time is divided into two signals, one signal is processed by the low-pass filter and the first limiter, the other signal is processed by the high-pass filter and the second limiter, and then the two processed signals enter the mixer to be mixed and outputted. The mixed output signal is subjected to second equalization filtering by the second equalization filter to avoid clipping distortion or to obtain a higher maximum sound level.

A limiter system for an active speaker may include at least one lowpass filter configured to receive an input signal and output a signal lower than a crossover frequency, at least one highpass filter, configured to receive an input signal and output a signal higher than the crossover frequency, a first allpass filter configured to adjust the phase of the signal lower than the crossover frequency, a second allpass filter configured to adjust the phase of the signal higher than the crossover frequency, a first limiter, configured to receive and limit the signal from the first allpass filter, a second limiter, configured to receive and limit the signal from the second allpass filter, and a mixer, configured to mix the signal lower from the first limiter and the signal from the second limiter.