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.

A speaker comprises a housing, a transducer residing inside the housing, and at least one sound guiding hole located on the housing. The transducer generates vibrations. The vibrations produce a sound wave inside the housing and cause a leaked sound wave spreading outside the housing from a portion of the housing. The at least one sound guiding hole guides the sound wave inside the housing through the at least one sound guiding hole to an outside of the housing. The guided sound wave interferes with the leaked sound wave in a target region. The interference at a specific frequency relates to a distance between the at least one sound guiding hole and the portion of the housing.

A headphone includes an electro-acoustic transducer, a housing, a noise cancelling circuit, a resonant frequency converter, and a switch. The electro-acoustic transducer is configured to reproduce sound from electrical signals. The housing is attached to the electro-acoustic transducer. The noise cancelling circuit is configured to attenuate a noise sound by adding an antiphase sound to the noise sound. The resonant frequency converter is configured to change a resonant frequency of a Helmholtz resonator configured to include a cavity in the housing and a tubular cavity communicating with the cavity. The switch is configured to perform alteration of the resonant frequency and switching of the noise cancelling circuit, in conjunction with each other.

A reference microphone for detecting noise is located under a first duct. The noise is in the form of a first plane wave in the first duct. A speaker is located on a top of the first duct. Connected to an upper part of the first duct is a second duct including an error microphone. The first plane wave in the first duct passes through an acoustic path and reaches the second duct. The error microphone detects the sound, and the speaker outputs a second plane wave with an opposite phase for canceling the first plane wave.

A device for reducing a rolling noise of a vehicle having at least one tire, the tire rolling on a roadway on a tire contact patch, wherein the device comprises at least one sound absorption element attached to the vehicle in front of, behind and/or laterally of the tire contact patch in the direction of travel (F) of the vehicle and having at least one resonance frequency and a curved first absorber membrane facing the tire contact patch, wherein the entire first absorber membrane is oriented normally to a direction of sound propagation (S) emanating from the tire contact patch, and the sound absorption element is located at a distance from the tire contact patch which corresponds to a multiple of half a wavelength (λ) assigned to the resonance frequency.

This disclosure includes several different features suitable for use in circumaural and supra-aural headphones designs. Designs that include earpad assemblies that improve acoustic isolation are discussed. User convenience features that include automatically detecting the orientation of the headphones on a user's head are also discussed. Various power-saving features, design features, sensor configurations and user comfort features are also discussed.

A device for generating acoustic compensation signals, which serve to compensate acoustic signals that result from the operation of a motor-vehicle drive unit. The device includes a signal-generating apparatus designed to generate acoustic compensation signals, which serve to compensate acoustic signals that result from the operation of a motor-vehicle drive unit, and a control apparatus, which is associated with the signal-generating apparatus and which is designed to control the operation of the signal-generating apparatus. The device also includes a determination apparatus, which is associated with the control apparatus and which is designed to determine the propagation direction of acoustic signals and to generate direction information describing the determined propagation direction of the acoustic signals. The control apparatus is further designed to control the operation of the signal-generating apparatus on the basis of corresponding direction information.

A speaker comprises a housing, a transducer residing inside the housing, and at least one sound guiding hole located on the housing. The transducer generates vibrations. The vibrations produce a sound wave inside the housing and cause a leaked sound wave spreading outside the housing from a portion of the housing. The at least one sound guiding hole guides the sound wave inside the housing through the at least one sound guiding hole to an outside of the housing. The guided sound wave interferes with the leaked sound wave in a target region. The interference at a specific frequency relates to a distance between the at least one sound guiding hole and the portion of the housing.

The present disclosure relates to the technical field of earphone and provides to an active noise reduction earphone. The active noise reduction earphone includes an earphone shell, a speaker, a sound outlet mouth, a first feedback digital microphone, a second feedback digital microphone and a sound collecting channel. Herein, the speaker divides the earphone shell into the front speaker cavity and the back speaker cavity; the sound outlet mouth is arranged to be faced to the speaker to output the sound emitted by the speaker; the first feedback digital microphone is arranged at the first noise reduction sound collecting hole preset in the back speaker cavity to collect external ambient noise; the sound in the ear canal is collected through the sound collecting channel, and the second feedback digital microphone isolates the sound collecting channel from the front speaker cavity.

A work machine includes a housing. The housing at least partly houses a machine. The housing has an opening. The work machine includes a path leading into the housing from the opening. The work machine includes a controller and a speaker. The controller is configured to cause a speaker to output a control sound for reducing operating noise. The operating noise is generated in the housing by motion of the machine and propagates in the path from a source of the operating noise to the opening. The speaker is arranged so that the control sound propagates in the path with its wavefront parallel to a wavefront of the operating noise that propagates in the path.