An active noise cancellation (ANC) system is provided with at least one loudspeaker to project an anti-noise sound within a room in response to receiving an anti-noise signal. A first controller is programmed to adjust a transfer function indicative of a secondary path between the at least one loudspeaker and at least one microphone within the room based on a resonance frequency of the at least one loudspeaker, and to generate the anti-noise signal based on the adjusted transfer function.

Methods for calibrating active noise-cancelling headphones, including placing the active noise-cancelling headphones on a measuring device; exciting the active noise-cancelling filter; measuring one or more relevant transmission pathways selected from x(n), m(n), and p(n) for feedforward and/or h(n) for feedback; defining at least one goal function for feedforward or feedback; calculating a complementary function for the defined goal function for at least one branch of the active noise-cancelling filter; calculating an impulse response of the complementary function from the measurements of the relevant transmission pathways; approximating operating parameters for the active noise-cancelling filter using the Prony method; and implementing the approximated operating parameters in the active noise-cancelling filter on the signal processor in order to create an approximated complementary active noise-cancelling filter, thereby calibrating the active noise-cancelling headphones.

A hybrid ANC system that can allow a feedback microphone to receive the same external noise as a feedforward microphone. A processor can generate an anti-noise signal based on what both microphones received to cancel a broader range of frequencies of the external noise.

Exemplary road and engine noise control systems and methods include directly picking up road noise from a structural element of a vehicle to generate a first sense signal representative of the road noise, directly picking up engine noise from an engine of the vehicle to generate a second sense signal representative of the engine noise, and combining the first sense signal and the second sense signal to provide a combination signal representing the combination of the first sense signal and the second sense signal. The systems and methods further include broadband active noise control filtering to generate a filtered combination signal from the combination signal, converting the filtered combination signal provided by the active noise control filtering into anti-noise and radiating the anti-noise to a listening position in an interior of the vehicle. The filtered combination signal is configured so that the anti-noise reduces the noise at the listening position.

In some embodiments, a method for evaluating headphones during a manufacturing process can include generating a test sound and measuring a response to the test sound from a headphone being evaluated. The method can further include configuring and/or calibrating the headphone based on the measurement. In some embodiments, such a method can be implemented as part of a process for manufacturing of a large number of headphones having active noise cancellation functionality.

A method at a wearable electronic device with: a first electro-acoustic input transducer and a second electro-acoustic input transducer arranged to pick up a first acoustic signal and convert the first acoustic signal to a first microphone signal and second microphone signal; and a third electro-acoustic input transducer arranged to pick up a second acoustic signal and convert the second acoustic signal to a third microphone signal; and a processor (140). The method comprises: generating a beamformed signal based on the first microphone signal (x1) and the second microphone signal; estimating a first frequency value representing a fundamental frequency in one or more of: the first microphone signal, the second microphone signal and the third microphone signal; configuring a first filter with one or more passbands at one or more integer multiples of the first frequency value and one or more stop bands adjacent the one or more stop bands; and filtering, using the first filter, one or more of: the first microphone signal, the second microphone signal and the beamformed signal.

Adaptive filters output a cancellation sound from a speaker, a selector selects outputs of a plurality of auxiliary filters each corresponding to different positions, a subtractor subtracts the selected output from the output of the microphone and outputs the subtracted output to the adaptive filter as an error signal, and a position detection device detects a position of a head of a user. A transfer function estimated so that the error signal becomes 0 when noise is canceled at the corresponding position is preset in the auxiliary filter. When the auxiliary filter corresponding to the position close to the head of the user changes, the switching control unit stepwise increases the frequency with which the output of the auxiliary filter is selected by the selector to 100%.

An ear cup housing has several reference microphones, an error microphone and a speaker. A processor drives the speaker for acoustic noise cancellation and transparency, by processing the microphone signals, and performs an oversight process by adjusting the reference microphone signals in response to detecting wind noise events and scratch events. In another aspect, the ear cup housing has an outside face that is joined to an inside face by a perimeter and the reference microphones are on the perimeter. Other aspects are also described and claimed.

There is provided an ear cup comprising a housing, an ear pad attached to the housing and arranged such that the housing and the ear pad together define a cavity having an opening, and an acoustic driver disposed within the cavity. The ear cup further comprises a feedforward microphone, a feedback microphone, and active noise control (ANC) circuitry. The active noise control (ANC) circuitry is configured to use a feedforward signal provided by the feedforward microphone to operate the acoustic driver to attenuate noise having frequencies within a feedforward ANC range having a lower limit of no less than 300 Hz and an upper limit of more than 1.5 kHz and to use a feedback signal provided by the feedback microphone to operate the acoustic driver to attenuate noise having frequencies within a feedback ANC range having an upper limit of no more than 1.5 kHz.

An acoustic echo cancellation unit includes: an audio processor configured to receive a multichannel audio signal and including: a first stage which is configured to process the multichannel audio signal to obtain a first set of spatial audio components; and a second stage which is configured to process the first set of spatial audio components to obtain a second set of spatial audio components; an echo cancellation processor configured to perform echo cancellation by use of the first set of spatial audio components or a deviated version of the first set of spatial audio components as reference signal.