Automatic volume controlling apparatus

Abstract

An apparatus for automatically controlling the sound volume of a sound producing apparatus based on ambient noise includes a microphone which detects the sound produced by the sound producing apparatus and ambient noise. Adaptive filters approximate, based on signals sent from the sound producing apparatus to speakers thereof, the characteristics of the sound components, relating to the sound produced by an individual speaker of the sound producing apparatus, which are received by the microphone. A subtractor subtracts the output of the adaptive filters from the output of the microphone to obtain a signal representing the ambient noise. The adaptive filters receive the signal representing the ambient noise and use this signal as a coefficient updating signal. A signal converter converts the signal representing ambient noise into an ambient noise level representing the volume of ambient noise. A controller then controls the gain by which amplifiers amplify signals sent from the sound producing apparatus to speakers thereof based on the ambient noise level.

Dependencies are inferred from the claim text.