Patent ID: 6021205
Filing Date: 2000-02-01
Classification: H04S

Abstract:
A headphone device comprising:signal processing means for performing signal processing on N-channel speech input signals, where N is an integer;power amplifying means for power amplifying speech signals processed by said signal processing means;a headphone driven by outputs from said power amplifying means; andangle of rotational movement detection means mounted on said headphone and including angle of rotational movement calculation means for receiving a detection output from said angle of rotational movement detection means and calculating an angle of rotational movement from a direction in front of a headphone user, in which signal processing contents in said signal processing means are updated responsive to said angle of rotational movement calculated by said angle of rotational movement calculation means for localizing a sound image in a preset localization direction outside said headphone user's head,wherein said signal processing means includes:2N digital filter means for convolving an impulse response converted into a time domain from a head transfer function for both ears of said headphone user from N sound sources placed at such positions as to localize said N-channel speech input signals in an angular range of 360.degree. outside said headphone user's head,a first pair of addition means for summing, respectively, all L outputs and all R outputs of 2M ones of said 2N digital filter means that are associated with M channels among said N channels, where M is an integer and N is not smaller than M,a second pair of addition means for summing, respectively, all L outputs and all R outputs of 2 (N-M) other ones of said 2N digital filter means associated with (N-M) other channels among said N channels,a first pair of time difference addition means respectively connected to L and R outputs of said first pair of addition means,a second pair of time difference addition means respectively connected to L and R outputs of said second pair of addition means,a third pair of addition means for summing, respectively, all L outputs and all R outputs of said first pair of time difference addition means and said second pair of time difference addition means,a first pair of level difference addition means respectively located on one of an input side and an output side of said first pair of time difference addition means, anda second pair of level difference addition means respectively located on one of an input side and an output side of said second pair of time difference addition means, whereinan increasing/decreasing direction of a time difference added to said L outputs by said first pair of time difference addition means and said second pair of time difference addition means is opposite an increasing/decreasing direction of a time difference added to said R outputs by said first pair of time difference addition means and said second pair of time difference addition means, and respective amounts of said time difference added to said L and R outputs depend on said angle of rotational movement detected by said angle of rotational movement calculation means and vary linearly with said angle of rotation movement for angles between -90.degree. to +90.degree., andan increasing/decreasing direction of a level difference added to said L outputs by said first pair of level difference addition means and said second level difference addition means is opposite an increasing/decreasing direction of a level difference added to said R outputs by said first pair of level difference addition means and said second pair of level difference addition means, and respective amounts of said level difference added to said L and R outputs depend on said angle of rotational movement detected by said angle of rotational movement calculation means and vary linearly with said angle of rotation movement for angles substantially between -90.degree. and +90.degree..