Patent ID: 6052470
Filing Date: 2000-04-18
Classification: H04S

Abstract:
A surround signal processing system comprising:first means for receiving a surround signal;second means for receiving a program of processing the surround signal;third means for decoding the surround signal received by the first means into multiple-channel signals according to the program received by the second means, the multiple-channel signals including a left surround signal and a right surround signal;fourth means for converting the multiple-channel signals generated by the third means into two-channel signals according to the program received by the second means;a pair of loudspeakers; andfifth means for transmitting the two-channel signals generated by the fourth means to the loudspeakers respectively;wherein the fourth means comprises filtering means for subjecting the left surround signal and the right surround signal generated by the third means to filtering processes according to the program received by the second means to convert the left surround signal and the right surround signal into filtering-resultant signals, the filtering processes being designed to localize sound images at rear positions symmetrical with respect to a listener when a rear loudspeaker is absent and only front loudspeakers are used, and means for generating the two-channel signals on the basis of the filtering-resultant signals; andwherein the filtering means comprises convolvers for processing the left surround signal and the right surround signal, the convolvers having filter coefficients Hl and Hr which are set on the basis of transfer functions as follows:Hl=(SF-AK)/(S.sup.2 -A.sup.2)Hr=(SK-AF)/(S.sup.2 -A.sup.2)where ""S"" denotes a transfer function from each of a pair of the loudspeakers to each listener's ear existing on the same side of each loudspeaker; ""A"" denotes a transfer function from each of a pair of the loudspeakers to each listener's ear existing on the opposite side of each loudspeaker; ""F"" denotes a transfer function from a position at which each sound image is required to be localized to each listener's ear existing on the same side of each loudspeaker; and ""K"" denotes a transfer function from a position at which each sound image is required to be localized to each listener's ear existing on the opposite side of each loudspeaker.