| 摘要 |
PROBLEM TO BE SOLVED: To provide a headphone apparatus capable of properly listening in ambient sound while listening in the intended audio signal source. SOLUTION: The headphone apparatus comprises a variable gain amplifier that amplifies external acoustic signal generated with left and right external acoustic microphone, a mixing amplifier that mixes the external acoustic signal amplified by the variable gain amplifier with listened acoustic signal that is inputted from a listened sound input and controlled for volume, left and right power amplifiers that power-amplify left and right acoustic signals mixed and generated with the mixing amplifier to drive left and right inner speakers, and a gain control means for controlling gain of the variable gain amplifier based on the listened sound level detected by a listened sound level detector and the external sound level detected by an external sound detector. COPYRIGHT: (C)2006,JPO&NCIPI |
