An active noise cancellation (ANC) system including a selectable decimation rate decimator that receives an oversampled digital input and has an input that selects the decimation rate, a filter that receives an output of the decimator, and a selectable interpolation rate interpolator that receives an output of the filter and has an input that selects the interpolation rate. The selectable decimation rate decimator and the selectable interpolation rate interpolator operate to provide a selectable sample rate for the filter based on the selected decimation and interpolation rates. The filter may be an anti-noise filter, feedback filter, and/or a filter that models an acoustic transfer function of the ANC system. Rate selection may be static, or dynamically controlled based on battery or ambient noise level. A ratio of the decimation rate and the interpolation rate is fixed independent of the dynamically controlled decimation and interpolation rates.

For example, a controller of an Active Acoustic Control (AAC) system may be configured to process input information, the input information including AAC configuration information corresponding to a configuration of AAC in a sound control zone; a plurality of noise inputs representing acoustic noise at a plurality of noise sensing locations; and a plurality of residual-noise inputs representing acoustic residual-noise at a plurality of residual-noise sensing locations within the sound control zone. For example, the controller may determine a sound control pattern to control sound within the sound control zone based on the AAC configuration information, the plurality of noise inputs, and the plurality of residual-noise inputs. For example, the controller may output the sound control pattern to a plurality of acoustic transducers.

The disclosure includes a headset comprising one or more earphones including one or more sensing components. The headset also includes one or more voice microphones to record a voice signal for voice transmission. The headset also includes a signal processor coupled to the earphones and the voice microphones. The signal processor is configured to employ the sensing components to determine a wearing position of the headset. The signal processor then selects a signal model for noise cancellation. The signal model is selected from a plurality of signal models based on the determined wearing position. The signal processor also applies the selected signal model to mitigate noise from the voice signal prior to voice transmission.

Method and system for active reduction of a predefined audio acoustic signal (AAAS), also referred to as noise, in a quiet zone, without interfering undefined acoustic noise signals within as well as outside the quiet zone, by generating accurate antiphase AAAS signal. The accuracy of the generated antiphase AAAS is obtained by employing a unique synchronization signal(s) (SYNC) which is generated and combined with the predefined AAAS. The combined signal is electrically transmitted (referred to as the electric channel) to a processing quieting component. Simultaneously, the generated SYNC signal is acoustically broadcasted near the predefined AAAS and merges with it. A microphone in the quiet zone receives the merged acoustic signals that arrive via the air (referred to as the acoustical channel) to the quiet zone and a receiver in the quieting component receives the combined electrical AAAS and SYNC signal that arrive wire or wireless to the quiet zone. In the quiet component the SYNC is detected from both electrical and acoustical channels, the detected SYNC signals with the electrically received AAAS signal are used to calculate the timing and momentary amplitude for generating an accurate acoustic antiphase AAAS signal to cancel the acoustic predefined AAAS. By continuously and periodically updating the SYNC signal enables to dynamically evaluate acoustical environmental distortions that might appear due to echo, reverberations, frequency non-linear response, or due to other distortions mechanisms.

Estimated output signals of the reference signals are generated using an estimated filter path transfer function that provides an estimated effect on sound waves traversing a physical path, the estimated filter path transfer function performing processing according to a diagonalization matrix and reference signals. Anti-noise signals are generated from the reference signals using an adaptive filter driven by learning unit signals received from a learning algorithm unit, the learning unit signals based in part on error output signals generated from the estimated output signals, the anti-noise signals including signals per sound zone and per reference signal, each sound zone including a microphone and one or more loudspeakers. A sum across references is performed on the anti-noise signals to generate a set of output signals per sound zone. The set of output signals are processed by the diagonalization matrix to generate a set of output signals per loudspeaker.

A method and device for detecting whether a headset is on ear. Microphone signals from a plurality of microphones are used to derive a plurality of signal feature measures, which are normalized to a common reference scale. The signal feature measures are weighted based upon detected signal conditions in the microphone signals. The normalized and variably weighted signal feature measures are then combined to produce an output indication of whether a headset is on ear.

A noise reducing comprises a first microphone that picks up noise signal at a first location and that is electrically coupled to a first microphone output path; a loudspeaker that is electrically coupled to a loudspeaker input path and that radiates noise reducing sound at a second location; a second microphone that picks up residual noise from the noise and the noise reducing sound at a third location and that is electrically coupled to a second microphone output path; a first active noise reducing filter that is connected between the first microphone output path and the loudspeaker input path; and a second active noise reducing filter that is connected between the second microphone output path and the loudspeaker input path; in which the first active noise reduction filter is a shelving or equalization filter or comprises at least one shelving or equalization filter or both.

A system for generating a transfer function indicating audio transmission characteristics of an input device associated with a processing device includes: a parameter determining unit configured to determine one or more parameters of the input device, where the parameters include a location of a microphone associated with the input device and a location of one or more respective input and/or output elements associated with the input device, an audio characteristic determining unit configured to determine one or more characteristics of audio transmission between respective input and/or output elements and the microphone, where the characteristics include one or more of an attenuation, resonance, and/or change in frequency profile of audio associated with the respective input and/or output element, and a transfer function generating unit configured to generate a transfer function in dependence upon the determined audio characteristics.

A sound control device mounted in a vehicle and control method thereof includes obtaining whether an audio function is ON or OFF, and determining a maximum limit value for a displacement of a speaker due to a noise control signal according to whether the audio function is ON or OFF.

In accordance with embodiments of the present disclosure, a processing system may include multiple selectable processing paths for processing an analog signal in order to reduce noise and increase dynamic range. Techniques are employed to transition between processing paths and calibrate operational parameters of the two paths in order to reduce or eliminate artifacts caused by switching between processing paths.