Patent ID: 6614912
Filing Date: 2003-09-02
Classification: H04R,H04S

Abstract:
A sound reproducing device comprising:an earphone device; a first signal processing device including a first signal processing circuit receiving an input audio signal of four channels and for converting the input audio signal to a first 2-channel audio signal with which a reproduced acoustic image is located at a predetermined position relative to a listener when the first 2-channel audio signal is connected to a first output terminal and reproduced by a 2-channel speaker system a second signal processing circuit receiving the first 2-channel audio signal and for subjecting the first 2-channel audio signal to signal processing equivalent to transfer functions of a 2-channel speaker system to both ears of a listener listening to the 2-channel speaker system, thereby converting the first 2-channel audio signal into a second 2-channel audio signal connected to a second output terminal, said second processing device processing the first 2-channel audio signal so that when the second 2-channel audio signal is reproduced over said earphone device connected to said second output terminal a reproduced acoustic image is located outside the head of a listener wearing the earphone device; and said earphone device including a pair of electroacoustic transducing means receiving the second 2-channel audio signal from said second signal processing circuit and including detection means for detecting a movement of the head of the listener wearing the earphone device, wherein said second signal processing circuit performs processing corresponding to an alteration of the transfer functions in accordance with the output of said detection means to control the location of the acoustic image perceived by the listener using the earphone device.