Patent ID: 6370253
Filing Date: 2002-04-09
Classification: H04R

Abstract:
An audio reproducing apparatus comprising:(a) a power amplifier for amplifying an input signal; (b) a speaker for reproducing an output signal from said power amplifier, said speaker being mounted to a baffle; (c) detecting means for detecting a movement of a voice coil disposed in said speaker; (d) a microphone disposed around said speaker; (e) an amplifier for amplifying an output signal supplied from said detecting means; (f) a bandwidth-passing-means for an output supplied from said amplifier; (g) a phase shifter for receiving an output signal from said bandwidth-passing-means; (h) adding means for adding electrically an output from said phase shifter and a lower frequency component of an output signal, including a noise around and a signal reproduced by said speaker, from said microphone; (i) converting means for converting an ac signal supplied from said adding means into a dc signal; and (j) control means for adjusting automatically a magnitude of the input signal responsive to the dc signal supplied from said converting means for preventing a reproduced sound from being masked with noise around said speaker, said control means disposed on an input side of said amplifier.