In one aspect a method that includes receiving an input signal captured by one or more first sensors associated with an active noise reduction (ANR) device, and processing the input signal using a first filter disposed in an ANR signal path to generate a first signal for an acoustic transducer of the ANR device. The input signal is processed in a pass-through signal path disposed in parallel with the ANR signal path to generate a second signal for the acoustic transducer, wherein the pass-through signal path allows a portion of the input signal to pass through to the acoustic transducer in accordance with a variable gain. One or more second sensors detect an existence of a condition likely to cause instability in the pass-through signal path, and in response, the variable gain is adjusted. A driver signal for the acoustic transducer is generated using an output based on the adjusted gain.

A noise reduction device and a method based on multi-sound production units thereof includes an audio processing chip, a power source configured to supply power to the audio processing chip, a microphone configured to collect environmental noise signals, a first sound production unit and a second sound production unit at least provided and configured to produce sound by an electro-acoustic conversion. The power source, the microphone, the first and second sound production units are electrically connected to the audio processing chip. The audio processing chip is configured to receive the environmental noise signals collected by the microphone and then output a reverse noise counteracted the environmental noise via the first sound production unit, and further configured to receive an input audio signal to be played and then output via the second sound production unit. The present disclosure can reduce noise without losing details of audio signals and ensure audio quality.

A speaker comprises a housing, a transducer residing inside the housing, and at least one sound guiding hole located on the housing. The transducer generates vibrations. The vibrations produce a sound wave inside the housing and cause a leaked sound wave spreading outside the housing from a portion of the housing. The at least one sound guiding hole guides the sound wave inside the housing through the at least one sound guiding hole to an outside of the housing. The guided sound wave interferes with the leaked sound wave in a target region. The interference at a specific frequency relates to a distance between the at least one sound guiding hole and the portion of the housing.

An in-ear device includes a housing shaped to hold the in-ear device in an ear of a user, and an audio package, disposed in the housing, to emit augmented sound. A first set of one or more microphones is positioned to receive external sound, and a controller is coupled to the audio package and the first set of one or more microphones. The controller includes a low-latency audio processing path, digital control parameters, and logic that when executed by the controller causes the in-ear device to perform operations. The operations may include receiving the external sound with the first set of one or more microphones to generate a low-latency sound signal; augmenting the low-latency sound signal by passing the low-latency sound signal through the low-latency audio processing path to produce an augmented sound signal; and outputting, with the audio package, the augmented sound based on the augmented sound signal.

Aspects relate to systems and methods for dynamic active noise reduction including at least a sensor configured to sense a physiological characteristic of a user and transmit a physiological signal correlated to the sensed physiological characteristic, at least an environmental microphone configured to transduce an environmental noise to an environmental noise signal, a processor configured to receive the environmental noise signal, generate a noise-reducing sound signal as a function of the environmental noise signal, and, modify the noise-reducing sound signal as a function of the physiological signal, and a speaker configured to transduce a noise-reducing sound from the modified noise-reducing sound signal.

A signal processing apparatus is provided which can suppress external noise without degrading an audio characteristic. Provided is a signal processing apparatus including: an A/D converter configured to output a digital signal having a predetermined sampling frequency and quantization bit number a, the A/D converter including a first delta sigma modulator that performs a first delta sigma modulation process on an input analog signal; a filter unit configured to pass an output of the A/D converter through a digital filter provided with a predetermined filter characteristic and output a digital signal having the sampling frequency and a quantization bit number b; a second delta sigma modulator configured to perform a second delta sigma modulation process on an output of the filter unit and output a digital signal having the sampling frequency and the quantization bit number a; and an addition unit configured to add an output of the second delta sigma modulator and an input digital signal having the sampling frequency and the quantization bit number.

Microphone signals of a primary headphone are processed and either a first transparency mode of operation is activated or a second transparency mode of operation. In another aspect, a processor enters different configurations in response to estimated ambient acoustic noise being lower or higher than a threshold, wherein in a first configuration a transparency audio signal is adapted via target voice and wearer voice processing (TVWVP) of a microphone signal to boost detected speech frequencies in the transparency audio signal, and in a second configuration the TVWVP is controlled to, as the estimated ambient acoustic noise increases, reduce boosting of, or not boost at all, the detected speech frequencies in the transparency audio signal. Other aspects are also described and claimed.

An audio system for a seat headrest includes N speaker(s), each configured to be integrated into a seat headrest, N being an integer greater than or equal to 1, and an audio processing device including an electronic transmission channel connected to the speaker(s) and configured to transmit at least one audio stream via the speaker(s). The audio system comprises P microphone(s), each configured to be integrated into the headrest, P being an integer greater than or equal to 1. The audio processing device further includes an electronic receiving channel connected to the microphone(s) and configured to receive at least one sound signal via the P microphone(s).

In one aspect a method that includes receiving an input signal captured by one or more first sensors associated with an active noise reduction (ANR) device, and processing the input signal using a first filter disposed in an ANR signal path to generate a first signal for an acoustic transducer of the ANR device. The input signal is processed in a pass-through signal path disposed in parallel with the ANR signal path to generate a second signal for the acoustic transducer, wherein the pass-through signal path allows a portion of the input signal to pass through to the acoustic transducer in accordance with a variable gain. One or more second sensors detect an existence of a condition likely to cause instability in the pass-through signal path, and in response, the variable gain is adjusted. A driver signal for the acoustic transducer is generated using an output based on the adjusted gain.

Technology described in this document can be embodied in an earpiece of an active noise reduction (ANR) device. The earpiece includes a plurality of microphones, wherein each of the plurality of microphones is usable for capturing ambient audio to generate input signals for both an ANR mode of operation and a hear-through mode of operation of the ANR device. The earpiece further includes a controller configured to: process a first subset of microphones from the plurality of microphones to generate input signals for the ANR mode of operation, process a second subset of microphones from the plurality of microphones to generate input signals for the hear-through mode of operation, detect that a particular microphone of the second subset is acoustically coupled to an acoustic transducer of the ANR device in the hear-through mode of operation, and in response to the detection, process the input signals from the second subset of microphones without using input signals from the particular microphone.