Signal mixing for a 5.1-channel surround sound system - Analysis and experiment

The image direction in 5.1-channel surround sound reproduction is analyzed by means of equations for multichannel sound localization. It is proven tha t by using pairwise signal mixing, a 5.1-channel system is capable of recre ating a stable image in the front directional area. The system is also capa ble of recreating an image in the rear directional area, and image directio n is frequency dependent. However, the image in the lateral directional are a is unstable. In particular there is a hole in the image in the area of 54 .6 degrees < theta < 110 degrees. Therefore the lateral image is very poor. A new signal mixing method is proposed which makes it possible to recreate a 360 degrees image within a reasonable frequency range (up to 800 Hz). Fi nally, a sound image localization experiment is carried out to prove the th eoretical analysis.