Sound image localization apparatus
A sound image localization apparatus comprises an L direct output section that produces an output signal by inputting an audio signal of a rear left audio input channel to a filter having a characteristic obtained by dividing RLD by LD, an L cross output section that produces an output signal by inputting the audio signal of the rear left audio input channel to a filter having a characteristic obtained by dividing RLC by LC, an R cross output section that produces an output signal by inputting an audio signal of a rear right audio input channel to a filter having a characteristic obtained by dividing RRC by RC, an R direct output section that produces an output signal by inputting the audio signal of the rear right audio input channel to a filter having a characteristic obtained by dividing RRD by RD, a first adding section that adds a difference signal between the output signal of the L direct output section and the output signal of the R cross output section to an audio signal of a front left audio input channel, and a second adding section that adds a difference signal between the output signal of the R direct output section and the output signal of the L cross output section to an audio signal of a front right audio input channel.
1. A sound image localization apparatus comprising:
an L direct output section that produces an output signal by inputting an audio signal of a rear left audio input channel to a filter having a characteristic obtained by dividing RLD by LD;
an L cross output section that produces an output signal by inputting the audio signal of the rear left audio input channel to a filter having a characteristic obtained by dividing RLC by LC;
an R cross output section that produces an output signal by inputting an audio signal of a rear right audio input channel to a filter having a characteristic obtained by dividing RRC by RC;
an R direct output section that produces an output signal by inputting the audio signal of the rear right audio input channel to a filter having a characteristic obtained by dividing RRD by RD;
a first adding section that adds a difference signal between the output signal of the L direct output section and the output signal of the R cross output section to an audio signal of a front left audio input channel; and
a second adding section that adds a difference signal between the output signal of the R direct output section and the output signal of the L cross output section to an audio signal of a front right audio input channel, wherein:
LD is a head-related transfer function which simulates spatial propagation from a real speaker FL disposed at a front-left position to a left ear;
LC is a head-related transfer function which simulates spatial propagation from the real speaker FL to a right ear;
RC is a head-related transfer function which simulates spatial propagation from a real speaker FR disposed at a front-right position to the left ear;
RD is a head-related transfer function which simulates spatial propagation from the real speaker FR to the right ear;
RLD is a head-related transfer function which simulates spatial propagation to the left ear from a virtual speaker VL which is disposed symmetrically with the real speaker FL with respect to a center line L that passes through the center of a head of a listener and extends in a right-left direction of the listener;
RLC is a head-related transfer function which simulates spatial propagation from the virtual speaker VL to the right ear;
RRC is a head-related transfer function which simulates spatial propagation to the left ear from a virtual speaker VR which is disposed symmetrically with the real speaker FR with respect to the center line L; and
RRD is a head-related transfer function which simulates spatial propagation from the virtual speaker VR to the right ear.
2. The sound image localization apparatus according to claim 1 , wherein the real speakers are set so as to be symmetrical with each other with respect to the right-left direction of the listener and the virtual speakers are set so as to be symmetrical with each other with respect to the right-left direction of the listener; and
wherein the head-related transfer functions LD and RD are identical, LC and RC are identical, RLD and RRD are identical, and RLC and RRC are identical.