A system and method includes an audio device, such as an earbud or headphones, that includes one or more loudspeakers for outputting audio. The audio device further in includes one or more microphones that are positioned near an ear of a user. An acoustic barrier may be formed between a surface of the device and the ear of the user; properties of this barrier may, however, vary from user to user. The system determines these properties on a per-user basis and compensates for any differences therein.

A noise-cancellation system with secondary path adaptation, includes: a noise-cancellation filter configured to receive a reference signal representative of a source of noise within a predefined volume and generating, based at least in part on the reference signal, a noise-cancellation signal that, when transduced by a speaker, produces a noise-cancellation acoustic signal that reduces noise in a cancellation zone within the predefined volume; a secondary path estimation filter configured to receive an input signal and to implement an estimate of secondary path transfer function, the secondary path transfer function being a transfer function between the speaker and a cancellation zone, the secondary path estimation filter outputting an output signal based, at least in part, on the estimate of the secondary path transfer function and the input signal; an adaptive module configured to adjust coefficients of the noise-cancellation filter according to a first adaptive algorithm, based, at least in part, on the estimated output signal; and an secondary path adaptive module configured to adjust coefficients of the secondary path estimation filter according to a second adaptive algorithm, wherein a rate of adaptation of the second adaptive algorithm is based, at least in part, on a coherence between the reference signal and an error signal representative of residual noise within the cancellation zone.

Active noise cancellation systems and methods include a feedforward path configured to receive a reference signal comprising ambient noise and adaptively generate an anti-noise signal to cancel the ambient noise and comprising an adaptive gain component configured to adaptively adjust a gain of the anti-noise signal, and a logic device configured to determine a leakage profile based on the adaptive gain component. The feedforward path includes a feedforward adaptive filter tuned to generate the anti-noise signal corresponding to the reference signal in accordance with the determined leakage profile. The leakage profile is selected from a plurality of stored leakage profiles that are tuned for a corresponding gain, and which corresponds to an ear coupling condition associated with a fit between the active noise cancellation system and a user. An adaptive transparency filter receives the reference signal and generates an ambient inclusion signal for output to a user.

An active noise control device includes an updated value table operating unit that writes initial values of an initial value table into an updated value table as updated values and writes updated coefficients of a secondary path filter C{circumflex over ( )} updated in a secondary path filter coefficient updating unit during active noise control, into the updated value table as updated values. The secondary path filter coefficient updating unit reads the updated value corresponding to a frequency from the updated value table before updating the coefficients of the secondary path filter C{circumflex over ( )}, and updates the coefficients of the secondary path filter C{circumflex over ( )}, using the read updated values as the pervious values.

An active noise reduction device includes: an impulsive signal generator that generates an impulsive signal; a signal output unit that outputs the impulsive signal to a loudspeaker; a signal detector that detects a rising signal and a falling signal from a microphone signal outputted from a microphone collecting sound; a connection determiner that determines, based on respective peak values of the rising signal detected and the falling signal detected, whether or not the loudspeaker is connected to the signal output unit; and a polarity determiner that determines a connection polarity between the loudspeaker and the signal output unit based on respective timings of the rising signal and the falling signal with respect to the impulsive signal, when it is determined that the loudspeaker is connected to the signal output unit.

A system for reducing noise for a user includes a first detector configured to generate a first noise signal, wherein the first noise signal is a representation of a first noise that is transmitted to the user through a first sound pathway, and a second detector configured to generate a second noise signal, wherein the second noise signal indicates a second noise perceived by the user. The system also includes a processor configured to determine a noise correction signal based on the first noise signal and/or the second noise signal, and a speaker configured to generate a sound for reducing the noise based on the noise correction signal.

Method for suppressing acoustic interfering signals, introduced into a passenger compartment of the motor vehicle, including: detecting a physical size in the passenger compartment of the motor vehicle, generating a detection information describing the detected physical size in the passenger compartment of the motor vehicle, selection of a counter-signal parameter influencing the acoustic counter-signal, depending upon the physical size described through the detection information, and/or adaptation of a counter-signal parameter influencing the acoustic counter-signal, depending upon the physical size described through the detection information, generating an acoustic counter-signal on the basis of the selected counter-signal parameter and/or on the basis of the adapted counter-signal parameter, and outputting the generated acoustic counter-signal into the passenger compartment of the motor vehicle to suppress acoustic interfering signals, introduced into the passenger compartment of the motor vehicle, resulting from the operation of the on-board drive unit.

A method of operating a headphone configured to be removed from and placed in close proximity to a user's ear can include generating an input signal by an input signal generating device. The method can also include determining whether an insertion event has occurred based on the generated input signal and causing the headphone to operate in a low power mode responsive to an absence of an insertion event determination after a first period of time. The method can also include causing the headphone to operate in an ultra-low power mode responsive to the absence of an insertion event determination after a second period of time that occurs after the first period of time, the ultra-low power mode having a lower power consumption than the low power mode.

A method of equalising sound in a headset comprising an internal microphone configured to generate a first audio signal, an external microphone configured to generate a second audio signal, a speaker, and one or more processors coupled between the speaker, the external microphone, and the internal microphone, the method comprising: while the headset is worn by a user: determining a first audio transfer function between the first audio signal and the second audio signal in the presence of sound at the external microphone; and determining a second audio transfer function between a speaker input signal and the first audio signal with the speaker being driven by the speaker input signal; determining an electrical transfer function of the one or more processors; determining a closed-ear transfer function based on the first audio transfer function, the second audio transfer function and the electrical transfer function; and equalising the first audio signal based on a comparison between the closed-ear transfer function and an open-ear transfer function to generate an equalised first audio signal.

A noise reduction system includes sensors configured to generate an input signal, an adaptive filter configured to represent a transfer function of a path traversed by the input signal, one or more processing devices, and one or more transducers. The processing devices receive the input signal and generate an updated set of filter coefficients of the adaptive filter by separating the input signal into frequency subbands; determining for each subband, coefficients of a corresponding subband adaptive module; and combining the coefficients of multiple subband adaptive modules. Determining the coefficients of the corresponding subband adaptive module includes selecting a subset of a precomputed set of filter coefficients of the adaptive filter. The processing devices process a portion of the input signal using the updated set of filter coefficients of the adaptive filter to generate an output that destructively interferes with another signal traversing the path represented by the transfer function.