Patent ID: 6944302
Filing Date: 2005-09-13
Classification: H04R

Abstract:
1. A sound reproducing apparatus comprising: a variable gain amplifier; a loudspeaker unit having a diaphragm, for reproducing an output of said power amplifier; a loudspeaker box for accommodating said loudspeaker; a microphone located near said loudspeaker box for capturing a mixed sound including a sound radiated from said loudspeaker unit and a noise around said loudspeaker box; a detector for detecting a physical quantity varying according to a motion of said diaphragm; a combining section for combining an output of said microphone and an output of said detector; and a comparing section for comparing an integral value obtained by integrating an output of said combining section and an integral value obtained by integrating an output of said variable gain amplifier, and for outputting a control signal for controlling said variable gain amplifier so that said integral values are equal to each other.