A method of generating a multi-channel audio signal includes: representing locations of a plurality of speakers as a plurality of polygons whose vertices are located at locations of corresponding speakers; acquiring a location of an object sound; calculating distances between the plurality of polygons and the location of the object sound; selecting one of the plurality of polygons on the basis of the calculated distances; and generating a multi-channel audio signal that corresponds to speakers corresponding to the selected polygon by mapping the object sound to the speakers corresponding to the selected polygon.