Inner Room Extension of a General Model for Spatial Processing of sounds

F. Richard Moore proposed a general model for spatial processing of sounds in 1982. [5] This model separates space in two nested areas. The outer room is an imagimary acoustic space within which the inner room (or the real performance space) is located. The inner room is denoted by the location of the speakers which simulate the sound heard in the inner room as if the speakers were “openings” connecting the inner and the outer room. The spatial impression is produced by diffusing simulated direct sound rays, early echos, and global reverbration of the sound sources as heard at each speaker location. The model does not allow sound to travel through the walls of the inner room, and thus, when sound sources are near the walls of the inner room, or travel through these walls, unexpected results may be heard in opposing speakers. Furthermore, the simulation of sound sources inside the inner room are not as convincing as simulation of sound sources outside the inner room. This paper discusses an inner room extension of the general model. This extension defines the inner room as multiple nested imaginary rooms, and it provides an improved ray intersection algorithm. It also slightly alters the algorithm by which the delay time and attenuation factors of the direct and reflected rays are calculated. This extension ameliorates a number of undesirable effects and, according to our subjective tests, provides a more convincing spatialization impression when the sound sources are inside the inner room.