In Order to establish a comprehensive method of evaluating reproduced sound quality, models of the process of sound quality evaluation were proposed. It was assumed that the total process of sound quality evaluation could be divided into two processes, an overall (emotional) process and an elemental sensory process, that formed a sensory factor of the former process. The elemental sensory process is described in terms of a multidimensional scale such as D_i=φ_i(t_j, s_i)(i=1, 2. . . , n), where t_j: a physical parameter showing the characteristics of a transmission system, s_i: components of S contributing to D_i. The elemental sensation D_i is assumed to have such relation with overall (emotional) response, R, (in reality, preference scale), as R=Σw_iD_i, where w_i=W(L, S, A), L: listener groups classified in terms of the similarity of preference, S: musical signal groups classfied by their effect on w_i, and A: age (time). The methodology to realize those models, especially that of the elemental sensory process, was discussed. According to this discussion, multidimensional scaling of the sensation of reproduced sound quality was made, varying the klirrfactor and the high-pass and low-pass filtering frequencies of transmission characteristics, as shown in Table 4. Fig. 15-17 show the three-dimensional scale thus obtained. In order find more definite relation between D_i and t_j, two more experiments were made. Table 1 shows the stimulus condition of an experiment on D_1. The inputoutput characteristics of a nonlinear distortion circuit are shown in Fig. 4. As shown in Fig. 5 and 6, a two-dimensional scale was calculated. But it was found that one-dimensional variation was only significant. Fig. 9 shows the relation between D_1, projections of the stimulus on the rotated unidimensional axis (dotted line) in Fig. 5 and 6 and the klirrfactor of the transmission system. Another experiment was concerned with D_2 and D_3. Stimulus condition is shown in Fig. 10 graphically. The two-dimensional centroid scales and rotated scale thus obtained are shown in Fig. 11 and 12. Fig. 13 and 14 show the graphic presentation of functions φ_2 and φ_3. These experiments only serve as the illustrations of our models. Several other experiments have been done, and from these experiments, we have found that five dimensions are enough for describing major sensory changes that will occur with usual variations in the physical characteristics of the transmission system.