An acoustic noise reduction, ANR, audio system comprising a headphone and having tap control means so as to allow a user to tap or touch the outside of the headphone as a means to instruct the performance of a desired function, the headphone comprising a cavity including a speaker and a feedback microphone, the ANR audio system further comprising: a first ANR module (12;12A) having a first ANR input to receive a first audio input signal, a second ANR input to receive a first supply current from a power supply, and an ANR output to provide a first audio output signal to the headphone speaker, the first audio output signal having an acoustic noise reduced over the acoustic noise, detected by the feedback microphone, that would be delivered within the headphone cavity in the absence of the first ANR module; a first current sensor (14;14A) having a sensor output and connected to the power supply, the first current sensor providing a signal responsive to a characteristic of the first supply current at the sensor output; a first signal conditioner module (16;16A) having an input connected to the sensor output of the first current sensor and having a first signal conditioner output, the first signal conditioner module providing a first conditioned signal at the first signal conditioner output in response to and according to the signal responsive to the characteristic of the first supply current; and an audio and mode control module having a first input to receive a source audio signal from an audio source, a second input connected to the first signal conditioner output, and a first output connected to the first ANR input of the first ANR module, the audio and mode control module being configured for controlling, in response to the first conditioned signal, at least one of: i/ a mode of operation of the headphone among music playback, telephone mode, talk through mode, a level of desired ANR, and audio source selection, and ii/ an attribute of the first audio input signal among volume, balance, mute, pause, forward or reverse playback, playback speed, selection of an audio source, and talk through mode; wherein the headphone is configured such that a tap event resulting from a user tapping or touching the outside of the headphone causes a pressure change in the headphone cavity that is detected by the feedback microphone of the headphone and which draws an extra current from the power supply to be consumed by the ANR system than that used to reduce the acoustic noise in the headphone cavity in the absence of said tapping or touching, and wherein the first signal conditioner module is configured for providing a first conditioned signal reflecting such extra current from the power supply, so that the audio and mode control module can change the mode of operation of the headphone or the attribute of the first audio input signal in response to a tap event having occurred. a first ANR module (12;12A) having a first ANR input to receive a first audio input signal, a second ANR input to receive a first supply current from a power supply, and an ANR output to provide a first audio output signal to the headphone speaker, the first audio output signal having an acoustic noise reduced over the acoustic noise, detected by the feedback microphone, that would be delivered within the headphone cavity in the absence of the first ANR module; a first current sensor (14;14A) having a sensor output and connected to the power supply, the first current sensor providing a signal responsive to a characteristic of the first supply current at the sensor output; a first signal conditioner module (16;16A) having an input connected to the sensor output of the first current sensor and having a first signal conditioner output, the first signal conditioner module providing a first conditioned signal at the first signal conditioner output in response to and according to the signal responsive to the characteristic of the first supply current; and an audio and mode control module having a first input to receive a source audio signal from an audio source, a second input connected to the first signal conditioner output, and a first output connected to the first ANR input of the first ANR module, the audio and mode control module being configured for controlling, in response to the first conditioned signal, at least one of: i/ a mode of operation of the headphone among music playback, telephone mode, talk through mode, a level of desired ANR, and audio source selection, and ii/ an attribute of the first audio input signal among volume, balance, mute, pause, forward or reverse playback, playback speed, selection of an audio source, and talk through mode; wherein the headphone is configured such that a tap event resulting from a user tapping or touching the outside of the headphone causes a pressure change in the headphone cavity that is detected by the feedback microphone of the headphone and which draws an extra current from the power supply to be consumed by the ANR system than that used to reduce the acoustic noise in the headphone cavity in the absence of said tapping or touching, and wherein the first signal conditioner module is configured for providing a first conditioned signal reflecting such extra current from the power supply, so that the audio and mode control module can change the mode of operation of the headphone or the attribute of the first audio input signal in response to a tap event having occurred.