CONTROLLER FOR A HEADPHONE ARRANGEMENT

摘要

A controller for a headphone arrangement (101) comprises a drive circuit (203) which generates a signal for an earphone (105) from an audio signal. The drive signal is fed to the earphone (105) causing this to reproduce the audio signal. A first circuit (217) determines a signal level for the audio signal and a second circuit (209) determines an ambient sound level from a microphone signal from a microphone (109). A third circuit (211) determines an attenuated ambient sound level for the user from the microphone signal and an ambient sound attenuation of the earphone (105). A gain controller (205) controls the gain of the audio drive circuit (203) for the audio signal in response to the ambient sound level, the attenuated ambient sound level and the signal level. The dynamic and automated gain control may be used to reduce the risk of hearing damage e.g. by automatically restricting the sound level experienced by the user to the ambient sound level.