An earphone device/test station pairing (1, 2) includes an earphone device (1) including: at least one electroacoustic driver (32, 33, 34); a digital module (31) including a processor module; and a digital interface configured to connect the earphone device (1) to a media/communications device having a digital output; a test station (2) including at least one transducer (40, 42, 6), the test station (2) being operative to communicate with the earphone device (1) via the digital interface to allow data transmission between the earphone device (1) and the test station (2) during a test/configuration procedure; and a test module (4) for performing automated testing of the earphone device (1) when mounted on/connected to the test station (2).

A sound system is provided with a headphone that includes a transducer and at least one microphone. The sound system also includes an equalization filter and a loop filter circuit. The equalization filter is adapted to equalize an audio input signal based on at least one predetermined coefficient. The loop filter circuit includes a leaky integrator circuit that is adapted to generate a filtered audio signal based on the equalized audio input signal and a feedback signal indicative of sound received by the at least one microphone, and to provide the filtered audio signal to the transducer.

With the noise reduction device (300), in identifying an acoustic transfer function that includes a path from the control speaker (340) to the error microphone (350) or the noise microphone (320) by outputting an identification sound from the control speaker (340) and detecting the identification sound with the error microphone (350) or the noise microphone (320), the identification controller (338) is configured to identify the acoustic transfer function by generating the identification sound from the white noise generator (337) when the seat detector (582) has detected that the seat is in the actual usage state for noise reduction.

An active noise control (ANC) system uses a proportional integral (PI) controller to produce a control signal based on feedback that comprises a combination of ambient sound and antinoise. The ANC system generates a corrected control signal based on the control signal and a configurable filtering parameter, and produces the antinoise under control of the corrected control signal such that the antinoise destructively interferes with frequencies of the ambient sound to produce the feedback. The ANC system uses a microphone to receive the feedback and provide the feedback to the PI controller.

Active noise control (ANC) is performed within a vehicle. Suppressed sound is produced by suppressing frequencies of ambient sound above a threshold frequency that enter an interior cavity of a sound-suppressing enclosure disposed within, and spaced from, interior walls of the vehicle. A microphone disposed within the interior cavity of the sound-suppressing enclosure receives feedback comprising a combination of the suppressed sound produced by the sound-suppressing enclosure and antinoise produced by one or more speakers mounted to a headrest disposed within the interior cavity of the sound-suppressing enclosure. The speakers are controlled to produce the antinoise based on the feedback, such that the antinoise destructively interferes with frequencies of the suppressed sound that are above the threshold frequency.

Active noise reduction (ANR) headphones and associated methods are provided. The ANR headphones may include a memory to store a plurality of profiles each including controller information and acoustic parameters in addition to a profile selection routine executable by a processor of the ANR headphone. The profile selection routine may be configured to identify acoustic characteristics of a subject wearing the ANR headphone, compare the acoustic characteristics of the subject with the acoustic parameters of the plurality of profiles, select a profile from the plurality of profiles based on the comparison between the acoustic characteristics of the subject with the acoustic parameters of the selected profile, and provide the controller information of the selected profile to a noise reduction circuit of the ANR headphone.

An active noise control (ANC) system uses a proportional integral (PI) controller to produce a control signal based on feedback that comprises a combination of ambient sound and antinoise. The ANC system generates a corrected control signal based on the control signal and a configurable filtering parameter, and produces the antinoise under control of the corrected control signal such that the antinoise destructively interferes with frequencies of the ambient sound to produce the feedback. The ANC system uses a microphone to receive the feedback and provide the feedback to the PI controller.

Active noise control (ANC) is performed within a vehicle. Suppressed sound is produced by suppressing frequencies of ambient sound above a threshold frequency that enter an interior cavity of a sound-suppressing enclosure disposed within, and spaced from, interior walls of the vehicle. A microphone disposed within the interior cavity of the sound-suppressing enclosure receives feedback comprising a combination of the suppressed sound produced by the sound-suppressing enclosure and antinoise produced by one or more speakers mounted to a headrest disposed within the interior cavity of the sound-suppressing enclosure. The speakers are controlled to produce the antinoise based on the feedback, such that the antinoise destructively interferes with frequencies of the suppressed sound that are above the threshold frequency.

A fixture for calibrating an active noise canceling (ANC) earphone, the calibration fixture including an ear model and an acoustic path. The ear model is configured to support an ANC earphone and includes an ear canal extending from an outer end of the ear canal to an inner end of the ear canal. The acoustic path is external to the ear canal and extends from, at a first end of the acoustic path, the inner end of the ear canal of the ear model to an opposite, second end of the acoustic path. The acoustic path is configured to transmit a mechanical sound wave received from the inner end of the ear canal to a region external to the ear model and adjacent the outer end of the ear canal.

A method for calibrating an ANC-enabled portable audio device having microphones plays continuously a calibration sound by a calibrated speaker of a test station separate from the device. For each microphone of all the microphones, a microphone calibration value is computed using a comparison of a predetermined level and a measured level of an audio signal transduced by the microphone in response to the continuously-played calibration sound. The calibration is done without using a microphone of the test station. A processing element of the device may be programmed to make the comparison and computation. The processing element also causes a speaker of the device to generate a second calibration sound, measures a second level while the computed calibration value is applied to one of microphones (e.g., error microphone), and computes a calibration value for the device speaker using a comparison of a predetermined level and the second level.