An active noise control (ANC) circuit is used for generating an anti-noise signal, and has a plurality of filters including at least one first filter and at least one second filter. The at least one first filter generates at least one first filter output, wherein each of the at least one first filter has a first filter type. The at least one second filter generates at least one second filter output, wherein each of the at least one second filter has a second filter type different from the first filter type. The anti-noise signal is jointly controlled by the at least one first filter output and the at least one second filter output. The at least one first filter and the at least one second filter are connected in a parallel fashion.

A noise reducing device includes: an acoustic-to-electric conversion section for collecting noise and outputting an analog noise signal; an analog-to-digital conversion section for converting the analog noise signal into a digital noise signal; and a digital processing section for generating a digital noise reducing signal on a basis of the digital noise signal and a desired parameter. The device further includes: a retaining section for retaining a plurality of parameters corresponding to a plurality of kinds of noise characteristics; a setting section for setting one of the plurality of parameters as the desired parameter of the digital processing section; a digital-to-analog conversion section for converting the digital noise reducing signal into an analog noise reducing signal; and an electric-to-acoustic conversion section for outputting noise reducing sound on a basis of the analog noise reducing signal.

A noise-cancelling headphone is provided that avoids an influence of the wind and prevents degradation in the sound quality of the reproduced sound output from a driver unit. The noise-cancelling headphone includes an ear piece including a housing unit having an interior and an exterior, a driver unit attached to the housing unit, and a microphone collecting external sounds at the exterior of the housing unit. The housing unit includes an accommodating portion accommodating the microphone and a sound collecting hole establishing the communication between the accommodating portion and the exterior of the housing unit. The accommodating portion is disposed in an upper portion of the housing unit of the noise-cancelling headphone when worn by the user. The sound collecting hole is open toward the upper side of the housing unit of the noise-cancelling headphone when worn by the user.

A noise reducing device includes: an acoustic-to-electric conversion section for collecting noise and outputting an analog noise signal; an analog-to-digital conversion section for converting the analog noise signal into a digital noise signal; and a digital processing section for generating a digital noise reducing signal on a basis of the digital noise signal and a desired parameter. The device further includes: a retaining section for retaining a plurality of parameters corresponding to a plurality of kinds of noise characteristics; a setting section for setting one of the plurality of parameters as the desired parameter of the digital processing section; a digital-to-analog conversion section for converting the digital noise reducing signal into an analog noise reducing signal; and an electric-to-acoustic conversion section for outputting noise reducing sound on a basis of the analog noise reducing signal.

An apparatus for improving a perceived quality of sound reproduction of an audio output signal is provided. The apparatus has an active noise cancellation unit for generating a noise cancellation signal based on an environmental audio signal, wherein the environmental audio signal has noise signal portions, the noise signal portions resulting from recording environmental noise. Moreover, the apparatus has a residual noise characteristics estimator for determining a residual noise characteristic depending on the environmental noise and the noise cancellation signal. Furthermore, the apparatus has a perceptual noise compensation unit for generating a noise-compensated signal based on an audio target signal and based on the residual noise characteristic. Moreover, the apparatus has a combiner for combining the noise cancellation signal and the noise-compensated signal to obtain the audio output signal.

A loudspeaker system is provided that includes a loudspeaker that is arranged in a baffle between a passenger compartment of a vehicle and the outside of the passenger compartment. The loudspeaker is configured to radiate an acoustical signal to the passenger compartment. The loudspeaker system further includes active noise control system wherein a microphone is acoustically coupled to the loudspeaker via a secondary path, and the loudspeaker is electrically coupled to the microphone via an active noise control filter.

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.

An echo cancellation system performs audio beamforming to separate audio input into multiple directions (e.g., target signals) and generates multiple audio outputs using two acoustic echo cancellation (AEC) circuits. A first AEC removes a playback reference signal (generated from a signal sent a loudspeaker) to isolate speech included in the target signals. A second AEC removes an adaptive reference signal (generated from microphone inputs corresponding to audio received from the loudspeaker) to isolate speech included in the target signals. A beam selector receives the multiple audio outputs and selects the first AEC or the second AEC based on a linearity of the system. When linear (e.g., no distortion or variable delay between microphone input and playback signal), the beam selector selects an output from the first AEC based on signal to noise (SNR) ratios. When nonlinear, the beam selector selects an output from the second AEC.

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.

In accordance with systems and methods of the present disclosure, an adaptive noise cancellation system may include an alignment filter configured to correct misalignment of a reference microphone signal and an error microphone signal by generating a misalignment correction signal.