Abstract: There is provided an ear cup including a housing containing a filter assembly and a motor-driven impeller for creating an airflow through the filter assembly, the housing including an air outlet downstream from the filter assembly for emitting the filtered airflow from the housing. The ear cup further includes an acoustic driver carried by or mounted to, either directly or indirectly, the housing, a reference internal noise sensor disposed within the housing, and a reference ambient noise sensor carried by or mounted to, either directly or indirectly, the housing. The ear cup further includes active noise control circuitry that is configured, in a first operating state, to use a signal provided by the reference internal noise sensor to operate the acoustic driver and, in a second operating state, to use a signal provided by the reference ambient noise sensor to operate the acoustic driver.

Abstract: There is provided an ear cup including a housing containing a filter assembly and a motor-driven impeller for creating an airflow through the filter assembly, the housing including an air outlet downstream from the filter assembly for emitting the filtered airflow from the housing. The ear cup further includes an acoustic driver carried by the housing, a reference internal noise sensor carried by the housing, and active noise control circuitry that is configured to use a signal provided by the reference internal noise sensor to operate the acoustic driver.

Abstract: There is provided an ear cup including a housing containing a filter assembly and a motor-driven impeller for creating an airflow through the filter assembly, the housing including an air outlet downstream from the filter assembly for emitting the filtered airflow from the housing. The ear cup further includes an acoustic driver mounted to the housing, a reference internal noise disposed within the housing and a reference ambient noise mounted to the housing. The ear cup further includes active noise control circuitry that is configured to simultaneously use both a signal provided by the reference internal noise and the signal provided by the reference ambient noise to operate the acoustic driver.

Abstract: 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.

Abstract: There is provided a head wearable air purifier comprising a first speaker assembly and a second speaker assembly, wherein the first speaker assembly comprises a filter assembly, an impeller for creating an airflow through the filter assembly, a motor arranged to drive the impeller and an air outlet downstream from the filter assembly for emitting a filtered airflow from the first speaker assembly. The head wearable air purifier further comprises a nozzle arranged to receive the filtered airflow from the first speaker assembly, the nozzle comprising an air outlet arranged to emit the received filtered airflow from the head wearable air purifier. The impeller is a mixed flow impeller that has a generally conical or frusto-conical shape, and both the impeller and the motor are disposed within an impeller casing that is generally frusto-conical in shape.

Abstract: There is provided a head wearable air purifier comprising a first speaker assembly and a second speaker assembly, wherein the first speaker assembly comprises a filter assembly, a motor-driven impeller for creating an airflow through the filter assembly, and an air outlet downstream from the filter assembly for emitting a filtered airflow from the speaker assembly. The head wearable air purifier further comprises a nozzle arranged to receive the filtered airflow from the first speaker assembly, the nozzle comprising an air outlet arranged to emit the received filtered airflow from the head wearable air purifier, and a control circuit arranged to control a rotational speed of the motor-driven impeller of the first speaker assembly such that the maximum rotational speed of the motor-driven impeller is from 9000 to 18,000 RPM.