Introduction to Acoustics

382 Part C Architectural Acoustics
Part C 10.4
a) Score
0.5
0
–0.5
b) Score
0.5
0
–0.5
–79.9
–0.19
0.46
80–82.9 83–85.9 86–
Listening level (dBA)
0.18
0.2–0.59 0.6–0.99 1–
Ät1/[Ät1]p
Fig. 10.50a–d Scores for each category of four physical factors obtained by the factor analyses. The number indicated at
the upper left part of each figure signifies the partial correlation coefficient between the score and each factor. (a) Listening
level; (b) normalized initial time delay gap between the direct sound and the first reflection; (c) IACC; (d) interaural time
delay of the IACC, τIACC, found as the most significant factor in this investigation with loudspeaker reproductions on the
stage. Tendencies obtained here are similar to those of the scale value shown in Fig. 10.7, which were obtained from the
simulated sound field
and sixty-four listeners, divided into 21 groups, were
seated in the specified set of seats. Without moving
from seat to seat and excluding the effects of other
physical factors such as visual and tactual senses on
judgments, subjective preference tests by the pairedcomparison
method were conducted, switching only the
loudspeakers on the stage. As a source signal, music
motif B was selected in the tests. Scale values
of preference were obtained by applying the law of
c)
d)
Score
0.5
0
–0.5
Score
0.5
0
–0.5
–0.39
0
0.25
0.4–0.69 0.7–
IACC
0.64
0.01–0.2 0.21–
ô IACC (ms)
comparative judgment and were reconfirmed by the
goodness of the fit [10.85, 86]. The session was repeated
five times, exchanging seats, and thus data for
14–16 subjects in total were obtained for each set of
seats.
Results of Multiple-Dimensional Analyses
In order to examine the relationship between scale values
of subjective preference and physical factors obtained