A personal audio device, such as a wireless telephone, includes noise canceling that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. The anti-noise signal is adaptively generated to minimize the ambient audio sounds at the error microphone. A processing circuit that performs the adaptive noise canceling (ANC) function also filters one or both of the reference and/or error microphone signals, to bias the adaptation of the adaptive filter in one or more frequency regions to alter a degree of the minimization of the ambient audio sounds at the error microphone.

Methods and systems for reducing a pressure wave are provided. In an exemplary embodiment, a motor vehicle comprises a cabin and a receiver positioned to detect an input pressure wave within the cabin and produce an input signal. A fan with a blade having a variable pitch is positioned within the vehicle where the fan is audible within the cabin. A processor is in communication with the receiver and the fan, where the processor is configured to receive the input signal and determine an input frequency and an input phase. The processor is further configured to instruct the fan to control a pitch of the blade to produce a cancellation pressure wave with a cancellation frequency that is about the same as the input frequency and a cancellation phase that is about 180° out of phase with the input phase.

A feedback noise reduction method, a feedback noise reduction system, and an earphone are provided. In the method, a channel morphological parameter of an acoustic channel between a microphone and a speaker in a feedback noise reduction system is detected; the feedback noise reduction system is switched from using a first noise reduction filter to using a second noise reduction filter in a case that it is determined that the acoustic channel is in an interfered state based on the channel morphological parameter; and a noise reduction signal is generated by using the second noise reduction filter to cancel a noise signal received by the feedback noise reduction system. A frequency response of the second noise reduction filter in a predetermined frequency band is less than a frequency response of the first noise reduction filter in the predetermined frequency band.

A wind noise suppression system may include a local wind noise suppression block, a receiver, and a wind noise suppression fusion block. The local wind noise suppression block may be configured to analyze an audio signal and generate, based on the audio signal, local wind noise information associated with a first device comprising the wind noise suppression system, wherein the local wind noise information includes parameters for suppressing local wind noise at the first device. The receiver may be configured to receive remote wind noise information associated with a second device, wherein the remote wind noise information includes parameters for suppressing remote wind noise at the second device. The wind noise suppression fusion block may be configured to combine the local wind noise information and the remote wind noise information into fused wind noise information and apply parameters of the fused wind noise information to modify audio information for playback to an audio transducer of the first device.

An apparatus is provided. The apparatus includes a plurality of flow guiding structures spatially aligned in a first row, each of the plurality of flow guiding structures comprising a fin-shape to funnel airflow at a trailing edge of each of the plurality of flow guiding structures. The apparatus also includes a plurality of flow separating structures spatially aligned in a second row interleaved between each of the plurality of flow guiding structures, each of the plurality of flow separating structures comprising a fin-shape configured to split airflow received from the plurality of flow guiding structures.

A feedback noise reduction method, a feedback noise reduction system, and an earphone are provided. In the method, a channel morphological parameter of an acoustic channel between a microphone and a speaker in a feedback noise reduction system is detected; the feedback noise reduction system is switched from using a first noise reduction filter to using a second noise reduction filter in a case that it is determined that the acoustic channel is in an interfered state based on the channel morphological parameter; and a noise reduction signal is generated by using the second noise reduction filter to cancel a noise signal received by the feedback noise reduction system. A frequency response of the second noise reduction filter in a predetermined frequency band is less than a frequency response of the first noise reduction filter in the predetermined frequency band.

A personal audio device, such as a wireless telephone, includes noise canceling that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. The anti-noise signal is adaptively generated to minimize the ambient audio sounds at the error microphone. A processing circuit that performs the adaptive noise canceling (ANC) function also filters one or both of the reference and/or error microphone signals, to bias the adaptation of the adaptive filter in one or more frequency regions to alter a degree of the minimization of the ambient audio sounds at the error microphone.

An acoustic measurement system for an industrial process asset includes a process measurement device providing a value representative of an acoustic signal near the industrial process asset based in part on a signal from an acoustic sensor positioned near the industrial process asset. A second acoustic sensor provides an acoustic value and a noise reduction component uses the acoustic value from the second acoustic sensor to affect the value provided by the process measurement device so that the value provided by the process measurement device is more representative of an acoustic signal generated by the industrial process asset.

An apparatus is provided. The apparatus includes a plurality of flow guiding structures spatially aligned in a first row, each of the plurality of flow guiding structures comprising a fin-shape to funnel airflow at a trailing edge of each of the plurality of flow guiding structures. The apparatus also includes a plurality of flow separating structures spatially aligned in a second row interleaved between each of the plurality of flow guiding structures, each of the plurality of flow separating structures comprising a fin-shape configured to split airflow received from the plurality of flow guiding structures.

A rotor blade with a leading edge and a trailing edge is provided, wherein the rotor blade is designed and configured for being exposed to a fluid flowing substantially from the leading edge to the trailing edge, the rotor blade includes at least two sensors designed for detecting flow characteristics of the fluid and providing respective sensor signals, and the rotor blade further includes at least two actuators for producing an anti-noise signal based on a sensor signal, the sensors are arranged spanwise and the actuators are arranged chordwise at the surface of the rotor blade, and the actuators are arranged and prepared such that flow-induced edge noise of the rotor blade, which is generated by the fluid, is at least partly cancelled out by the anti-noise signal. Also provided is a method for creating such rotor blade and a related wind turbine.