PROCEEDINGS of the23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

A Study on Discrimination of Acoustic Conditions in an Audience
Area of an AuditoriumYasunobu TOKUNAGA1; Ryo INOUE1; Takane TERASHIMA2
1

National Institute of Technology, Maizuru College2

Mie University

ABSTRACTThe purpose of this study is to clarify the acoustical difference depending on the seat position in anauditorium, particularly the level of difference perceivable by the audience and acoustical cues for perceptionof difference.
Subjects were presented through headphones with pairs of impulse responses measured in different positionsof an auditorium, and then answered for questions whether two impulse responses sounded the same or not.
Answers of the subjects were subjected to cluster analysis and multidimensional analysis so that the audiencearea, which was previously divided into several zones, was grouped according to acoustic similarity.
As a result of comparison between the subject's answer and objective measurement obtained by the impulse
responses in respective seats, it is likely that the subjects perceived the difference in the acoustic conditions
on the basis of not only the subjective level of sound but also the perceived clarity of sound and perceived
reverberance.
Keywords: Impulse Response, Subjective Judgment, Discrimination

1. INTRODUCTION
Acoustic characteristics of a music hall are sometimes expressed by a representative value ofreverberation time. Since the acoustic condition, however, differs among audience seat s, ISO3382-1
defines a standard of the number of measurement points to be set for acoustic measurement in audienceseats of a hall1.
Meanwhile, in consideration of human auditory sense, it is quite difficult to recognize all thedifferences in acoustic condition among audience seats, even though the acoustic condition differs foreach seat in a strict sense. In particular, even different acoustic conditions can be perceived as identical
if the difference is not more than a threshold. Although such conditions are actually different in termsof physical quantity, they can be regarded as identical from the psychological point of view of theaudience.
Prior studies have been carried out by Wilkens 2 , Yamaguchi3, and Edwards 4, for example. In thesestudies, the dissimilarity of acoustic conditions according to determination by subjects was found,while the relationship between the determination by subjects and acoustic properties was discussed.
The authors consider that the acoustic conditions in audience seats in a hall can be zoned on the basisof subjective determination by the audience, if the extent of perceivable difference is clarified.
The purpose of this study is to specify the extent of difference in acoustic condition perceivable byaudience and a factor for the determination of difference in various seat positions of a hall. In addition,
the difference in acoustic condition determined by subjects was analyzed to divide the audience seats
into several zones each including seats determined to be acoustic ally identical.

2. EXPERIMENTS
2.1 Outline
The impulse response was measured at various points in an audience area of a music hall, and the1

tokunaga@maizuru-ct.ac.jp4583

measured impulse responses were paired. Each pair of impulse responses was presented to a subject.
The subject answered whether the first and second impulse responses sounded the same or different.
The experiment involved 20 subjects.
2.2 Preparation
The music hall used for the measurement of impulse response has 1410 seats. In the hall with aomnidirectional loudspeaker (D-10, Globo Technology) set at the center of the stage and monauralmicrophones (AT4050, Audio-Technica) set at several positions of the audience area, monaural
impulse responses were recorded. The measurement of impulse response was carried out with thewhole audience area of the hall divided into three areas, that is, Large area, Medium area, and Smallarea. Large area refers to the whole audience area (the number of impulse response measurement
points: 12 points). Medium area refers to the vicinity of central area of the audience area (the numberof impulse response measurement points: 9 points). Small area refers to an area where the interval
between seats is narrower than that of Medium area (the number of impulse response measurement
points: 12 points). Figure 1 shows the impulse response measurement points. The impulse responses
were measured with the gain of the microphone kept constant so as to reproduce the difference insound level depending on the sound receiving position.

Figure 1 – Impulse response measurement points
The impulse responses measured at the positions illustrated above were used to prepared pairs ofstimuli to be presented to the subjects as shown in Figure 2. Two impulse responses measured in thesame area constitute each pair of stimuli. A pause of one second was provided between the two impulse
responses. In order to confirm the reliability of answers from the subjects, five pairs of identical
impulse responses were additionally prepared for each area and presented to the sub jects.

Figure 2 – Example of stimuli presented4584

2.3 Procedure
The subject listened to a pair of impulse responses through headphones (MDR -CD900ST, SONY)and subsequently answered whether the two impulse responses sounded the same or different. In thecase where the subject desired to listen to the pair of impulse responses again, it was presented to thesubject each time. The subject listened to 71 pairs of stimuli (66 kinds of pairs of stimuli + 5 pairs ofidentical stimuli) for Large area, 41 pairs of stimuli (36 kinds of pairs of stimuli + 5 pairs of identicalstimuli) for Medium area, and 71 pairs of stimuli (66 kinds of pairs of stimuli + 5 pairs of identicalstimuli) for Small area, and answered.
The experiment was carried out for each area, and the order of stimuli to be presented was randomly
set. The volume of sound to be received by the subject was adjusted with use of a headphone amplifier(HUD-mx2, Audinst) so that the sound reproduced through the headphones was appropriate. As aresult of the adjustment, L Amax of the sound of measurement point 2, which was nearest to the soundsource, was 78.5[dB].

3. RESULT AND DISCUSSION
3.1 Result of answer from subject
Tables 1 to 3 show the result of experiment regarding Large area, Medium area, and Small area,respectively.
Table 1 – The number of cases where impulse responses of each pair were determined as different,Large area㻝㻞㻝㻡㻝㻞㻟㻠㻡㻢㻣㻤㻥㻝㻜㻝㻝㻝㻞㻟㻠㻝㻝㻠㻝㻡㻝㻠㻝㻟㻡㻝㻠㻥㻝㻡㻝㻞㻢㻝㻟㻝㻜㻥㻞㻝㻟㻣㻥㻝㻤㻝㻤㻝㻜㻝㻟㻝㻝㻤㻝㻞㻝㻢㻝㻤㻥㻝㻜㻝㻢㻟㻥㻝㻡㻝㻥㻝㻟㻝㻞㻝㻠㻣㻣㻥㻝㻜㻝㻤㻝㻣㻝㻡㻝㻟㻝㻠㻣㻣㻤㻥㻝㻝㻝㻣㻝㻥㻝㻣㻣㻣㻣㻤㻥㻥㻝㻜㻝㻞㻝㻣㻝㻤㻝㻡㻝㻝㻝㻞㻢㻝㻟㻥㻢㻡㻢

Table 2 – The number of cases where impulse responses of each pair were determined as different,
Medium area㻝㻟㻝㻠㻝㻢㻝㻟㻝㻠㻝㻡㻝㻢㻝㻣㻝㻤㻝㻥㻞㻜㻞㻝㻝㻡㻝㻜㻤㻝㻢㻡㻝㻡㻝㻞㻝㻣㻝㻝㻝㻠㻝㻟㻢㻝㻤㻣㻝㻡㻝㻜㻢㻡㻝㻥㻝㻢㻝㻣㻝㻥㻝㻜㻝㻞㻝㻜㻞㻜㻝㻡㻞㻜㻝㻥㻝㻡㻝㻞㻝㻣㻥㻞㻝㻝㻢㻝㻥㻝㻤㻝㻟㻥㻝㻝㻡㻣

Table 3 – The number of cases where impulse responses of each pair were determined as different,
Small area㻞㻞㻞㻞㻞㻟㻞㻠㻞㻡㻞㻢㻞㻣㻞㻤㻞㻥㻟㻜㻟㻝㻟㻞㻟㻟㻞㻟㻝㻟㻞㻠㻟㻣㻞㻡㻢㻥㻡㻞㻢㻢㻟㻢㻡㻞㻣㻝㻝㻝㻣㻝㻢㻢㻝㻝㻞㻤㻝㻜㻠㻝㻟㻝㻞㻝㻜㻝㻠㻞㻥㻝㻜㻤㻥㻝㻝㻥㻝㻡㻝㻣㻟㻜㻟㻝㻝㻡㻣㻡㻟㻤㻝㻡㻟㻝㻣㻥㻣㻝㻜㻤㻝㻝㻝㻝㻢㻝㻡㻟㻞㻝㻠㻣㻝㻢㻝㻡㻝㻠㻝㻤㻝㻜㻤㻞㻜㻝㻜㻟㻟㻝㻞㻣㻝㻞㻝㻝㻥㻝㻠㻝㻝㻣㻝㻡㻣㻤

4585

The values in the tables each indicate the number of answers "sounded different". That is, a larger
value indicates that two impulse responses of the pair were perceived as more different by subjects,
and thus the dissimilarity between such impulse responses is construed as being higher.
Throughout the experiment, each subject was required to answer regarding 15 pairs of identical
impulse responses. Identical impulse responses were sometimes determined as "sounded different" asa matter of course; however, no subject made more than 50% wrong answers, and therefore all theanswers from the 20 subjects were taken as targets of analysis. The highest percentage of wrong
answers of a subject was 33.3%, and an average percentage of wrong answers of all the 20 subjects was10.3%. Seven subjects answered "sounded the same" regarding 15 pairs of identical stimuli.
3.2 Analysis by multi dimensional scaling
Results shown in Tables 1 to 3 were subjected to multi dimensional scaling (MDS) to be plotted as
illustrated in Figure 3. Impulse responses of a pair determined as "sounded the same" by many subjects
were determined as quite similar to each other and plotted at near positions in a three-dimensionalspace.
The stress in the figure is an index regarding the goodness of fit of the spatial model obtained byMDS. The goodness of fit of the model increases as the stress value decreases. According to K ruskal5 ,Large area and Small area are evaluated as fair, whereas Medium area is evaluated as good in terms ofgoodness of fit of this case obtained by MDS.

Figure 3 – Stimuli plotted on graphs obtained by MDS
Coordinate axes obtained by MDS can be understood by comparison between the coordinate valueof each stimulus obtained by MDS and the tendency of fluctuation of acoustic index for each stimulus.
Tables 4, 5, and 6 show correlation coefficients between the coordinate values obtained by MDS andthe objective parameters of stimuli for the respective areas. A-value in each table indicates a value
calculated from amplitude ratio between direct sound and reflected sound of impulse response 6. The
A-value tends to be small in the case of dominant direct sound.
Table 4 – Correlation coefficient between Dim. obtained by MDS and objective parameter, Largearea㻰㼕㼙㻚㻝4586㻰㼕㼙㻚㻞㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻿㻼㻸㻌㼇㼐㻮㼉㻙㻜㻚㻥㻝㻝 㻖㻖㻙㻜㻚㻡㻟㻠㻙㻜㻚㻥㻟㻢 㻖㻖㻭㻙㼢㼍㼘㼡㼑㻌㼇㻙㼉㻜㻚㻠㻤㻜㻜㻚㻡㻢㻠㼀㻞㻜㻌㼇㼟㼉㻜㻚㻤㻜㻤㻖㻖㼀㻟㻜㻌㼇㼟㼉㻜㻚㻟㻡㻠㻱㻰㼀㻌㼇㼟㼉㻰㼕㼙㻚㻟㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻙㻜㻚㻤㻡㻢 㻖㻖㻜㻚㻞㻠㻥㻙㻜㻚㻝㻡㻤㻜㻚㻞㻜㻡㻜㻚㻡㻟㻞㻜㻚㻡㻝㻤㻜㻚㻜㻟㻝㻙㻜㻚㻝㻥㻝㻜㻚㻞㻣㻤㻜㻚㻜㻜㻞㻜㻚㻡㻢㻞㻙㻜㻚㻟㻥㻢㻜㻚㻡㻝㻤㻙㻜㻚㻜㻥㻤㻜㻚㻢㻜㻞 㻖㻙㻜㻚㻝㻤㻢㻙㻜㻚㻤㻢㻟 㻖㻖㻙㻜㻚㻠㻣㻠㻙㻜㻚㻣㻢㻡 㻖㻖㻙㻜㻚㻤㻝㻝 㻖㻖㻯㻡㻜㻌㼇㼐㻮㼉㻙㻜㻚㻜㻠㻟㻙㻜㻚㻠㻜㻠㻜㻚㻠㻟㻞㻯㻤㻜㻌㼇㼐㻮㼉㻜㻚㻢㻢㻣 㻖㻜㻚㻢㻜㻞 㻖㻰㻡㻜㻌㼇㻑㼉㻙㻜㻚㻜㻠㻡㻙㻜㻚㻠㻢㻜㼀㼟㻌㼇㼟㼉㻖㻙㻜㻚㻢㻟㻞㻙㻜㻚㻠㻝㻟㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻜㻚㻞㻡㻤㻙㻜㻚㻜㻢㻣㻜㻚㻠㻟㻡㻙㻜㻚㻜㻠㻢㻙㻜㻚㻞㻟㻡㻙㻜㻚㻝㻜㻟㻙㻜㻚㻝㻠㻡㻜㻚㻡㻟㻡㻜㻚㻟㻡㻜㻜㻚㻝㻣㻤㻜㻚㻠㻢㻟㻜㻚㻜㻝㻢㻜㻚㻝㻟㻞㻙㻜㻚㻠㻟㻤㻙㻜㻚㻜㻥㻝㻙㻜㻚㻡㻢㻡㻙㻜㻚㻞㻝㻤㻜㻚㻟㻝㻡㻜㻚㻜㻜㻝㻜㻚㻞㻜㻣㻙㻜㻚㻟㻠㻟㻜㻚㻜㻠㻣㻙㻜㻚㻡㻢㻠㻙㻜㻚㻞㻥㻟㻜㻚㻟㻣㻤㻙㻜㻚㻞㻜㻣㻜㻚㻟㻝㻞㻜㻚㻜㻜㻣㻙㻜㻚㻞㻢㻡㻜㻚㻝㻥㻤㻙㻜㻚㻝㻠㻢㻜㻚㻜㻡㻜㻜㻚㻞㻟㻝㻙㻜㻚㻞㻞㻤㻙㻜㻚㻜㻤㻢㻙㻜㻚㻝㻠㻜㻜㻚㻜㻟㻤㻙㻜㻚㻜㻞㻤㻙㻜㻚㻟㻠㻟㻙㻜㻚㻢㻟㻣 㻖㻙㻜㻚㻢㻤㻟 㻖㻙㻜㻚㻞㻡㻞㻜㻚㻣㻡㻜 㻖㻖㻜㻚㻠㻜㻞㻜㻚㻞㻤㻟㻙㻜㻚㻟㻤㻞㻜㻚㻝㻡㻢㻜㻚㻟㻢㻣㻙㻜㻚㻟㻥㻡㻙㻜㻚㻜㻢㻠㻙㻜㻚㻠㻢㻠㻙㻜㻚㻠㻠㻜㻜㻚㻠㻞㻥㻙㻜㻚㻞㻟㻟㻙㻜㻚㻜㻤㻢㻙㻜㻚㻜㻠㻣㻜㻚㻜㻟㻤㻙㻜㻚㻜㻞㻤㻙㻜㻚㻟㻠㻞㻙㻜㻚㻢㻡㻝 㻖㻙㻜㻚㻢㻣㻣 㻖㻙㻜㻚㻞㻡㻞㻙㻜㻚㻞㻟㻥㻙㻜㻚㻝㻥㻟㻜㻚㻟㻤㻜㻙㻜㻚㻝㻣㻣㻙㻜㻚㻞㻞㻢㻜㻚㻠㻢㻝㻜㻚㻜㻤㻝㻜㻚㻠㻠㻥㻜㻚㻡㻜㻡㻙㻜㻚㻣㻠㻤㻖㻖

Table 5 – Correlation coefficient between Dim. obtained by MDS and objective parameter, Mediumarea㻰㼕㼙㻚㻝㻰㼕㼙㻚㻞㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻿㻼㻸㻌㼇㼐㻮㼉㻙㻜㻚㻥㻡㻥 㻖㻖㻙㻜㻚㻢㻢㻣 㻖㻙㻜㻚㻥㻞㻣 㻖㻖㻭㻙㼢㼍㼘㼡㼑㻌㼇㻙㼉㻙㻜㻚㻝㻠㻞㻜㻚㻜㻜㻜㼀㻞㻜㻌㼇㼟㼉㻜㻚㻠㻤㻢㼀㻟㻜㻌㼇㼟㼉㻰㼕㼙㻚㻟㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻙㻜㻚㻥㻡㻜 㻖㻖㻙㻜㻚㻝㻜㻢㻙㻜㻚㻡㻣㻥㻙㻜㻚㻞㻟㻤㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻙㻜㻚㻜㻢㻢㻜㻚㻜㻢㻤㻜㻚㻝㻞㻜㻜㻚㻠㻥㻤㻙㻜㻚㻢㻝㻞㻙㻜㻚㻡㻞㻠㻙㻜㻚㻞㻢㻟㻙㻜㻚㻝㻝㻣㻜㻚㻜㻡㻤㻙㻜㻚㻟㻢㻥㻙㻜㻚㻜㻡㻢㻙㻜㻚㻠㻞㻡㻙㻜㻚㻜㻡㻝㻙㻜㻚㻣㻣㻤 㻖㻙㻜㻚㻟㻜㻤㻙㻜㻚㻤㻞㻜 㻖㻖㻙㻜㻚㻝㻠㻣㻜㻚㻝㻢㻡㻙㻜㻚㻞㻢㻤㻜㻚㻡㻤㻝㻙㻜㻚㻞㻟㻝㻜㻚㻟㻞㻤㻜㻚㻞㻢㻠㻙㻜㻚㻝㻥㻟㻜㻚㻝㻡㻤㻜㻚㻜㻤㻟㻙㻜㻚㻢㻡㻣㻙㻜㻚㻢㻜㻥㻜㻚㻝㻠㻠㻙㻜㻚㻟㻢㻤㻜㻚㻜㻝㻠㻙㻜㻚㻜㻞㻥㻙㻜㻚㻞㻞㻢㻙㻜㻚㻝㻣㻢㻙㻜㻚㻟㻣㻤㻙㻜㻚㻟㻜㻡㻙㻜㻚㻠㻜㻢㻱㻰㼀㻌㼇㼟㼉㻙㻜㻚㻡㻣㻡㻜㻚㻟㻡㻟㻙㻜㻚㻡㻤㻤㻙㻜㻚㻟㻝㻜㻜㻚㻞㻡㻢㻜㻚㻟㻡㻡㻜㻚㻡㻣㻠㻜㻚㻡㻥㻠㻜㻚㻟㻠㻢㻜㻚㻟㻣㻞㻙㻜㻚㻝㻢㻞㻜㻚㻠㻞㻡㻯㻡㻜㻌㼇㼐㻮㼉㻙㻜㻚㻢㻝㻡㻙㻜㻚㻟㻜㻝㻜㻚㻡㻡㻜㻙㻜㻚㻡㻡㻤㻜㻚㻠㻟㻜㻙㻜㻚㻜㻣㻤㻙㻜㻚㻢㻡㻝㻙㻜㻚㻜㻥㻜㻙㻜㻚㻜㻟㻜㻙㻜㻚㻜㻜㻡㻙㻜㻚㻜㻝㻢㻙㻜㻚㻞㻤㻝㻜㻚㻜㻞㻞㻯㻤㻜㻌㼇㼐㻮㼉㻜㻚㻟㻞㻞㻜㻚㻠㻝㻣㻜㻚㻥㻡㻠 㻖㻖㻜㻚㻜㻝㻟㻙㻜㻚㻞㻝㻜㻙㻜㻚㻣㻟㻝 㻖㻜㻚㻜㻣㻠㻙㻜㻚㻞㻞㻜㻙㻜㻚㻝㻞㻤㻙㻜㻚㻜㻟㻜㻙㻜㻚㻜㻤㻠㻙㻜㻚㻟㻝㻤㻖㻙㻜㻚㻜㻥㻜㻙㻜㻚㻜㻞㻡㻙㻜㻚㻜㻜㻠㻙㻜㻚㻜㻡㻥㻙㻜㻚㻞㻤㻢㻜㻚㻜㻞㻝㻜㻚㻝㻢㻥㻜㻚㻞㻥㻝㻜㻚㻟㻡㻡㻙㻜㻚㻜㻝㻞㻜㻚㻟㻝㻢㻜㻚㻟㻣㻜㻰㻡㻜㻌㼇㻑㼉㻙㻜㻚㻢㻝㻡㻙㻜㻚㻟㻠㻣㻜㻚㻡㻠㻞㻙㻜㻚㻡㻡㻢㻙㻜㻚㻜㻣㻣㻙㻜㻚㻢㻤㻡㼀㼟㻌㼇㼟㼉㻙㻜㻚㻝㻠㻠㻙㻜㻚㻟㻜㻡㻙㻜㻚㻤㻣㻣 㻖㻖㻙㻜㻚㻜㻤㻤㻜㻚㻞㻠㻟㻜㻚㻣㻟㻤 㻖

Table 6 – Correlation coefficient between Dim. obtained by MDS and objective parameter, Smallarea㻰㼕㼙㻚㻝㻭㻼㻿㻼㻸㻌㼇㼐㻮㼉㻙㻜㻚㻥㻞㻝㻭㻙㼢㼍㼘㼡㼑㻌㼇㻙㼉㻜㻚㻠㻝㻢㼀㻞㻜㻌㼇㼟㼉㻜㻚㻞㻢㻣㻖㻖㻰㼕㼙㻚㻞㻰㼕㼙㻚㻟㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻖㻖㻖㻖㻜㻚㻞㻠㻡㻜㻚㻠㻢㻝㻜㻚㻠㻤㻟㻜㻚㻠㻥㻟㻜㻚㻡㻣㻡㻜㻚㻜㻥㻟㻙㻜㻚㻤㻝㻞 㻖㻖㻙㻜㻚㻜㻢㻤㻙㻜㻚㻣㻢㻞㻖㻖㻙㻜㻚㻣㻣㻥 㻖㻖㻙㻜㻚㻝㻞㻠㻙㻜㻚㻠㻟㻞㻙㻜㻚㻥㻝㻞㻜㻚㻞㻣㻣㻜㻚㻟㻡㻡㻜㻚㻟㻠㻞㻜㻚㻠㻣㻢㻙㻜㻚㻝㻞㻢㻜㻚㻝㻜㻟㻜㻚㻟㻢㻥㻙㻜㻚㻣㻠㻟 㻖㻖㻙㻜㻚㻣㻤㻠㻭㻼㻝㻞㻡㻌㼇㻴㼦㼉㻡㻜㻜㻌㼇㻴㼦㼉 㻞㻜㻜㻜㻌㼇㻴㼦㼉㻙㻜㻚㻜㻜㻞㻙㻜㻚㻞㻢㻟㻜㻚㻝㻠㻡㻙㻜㻚㻢㻣㻞 㻖㻜㻚㻜㻢㻡㻜㻚㻝㻞㻟㻙㻜㻚㻟㻢㻟㻙㻜㻚㻜㻞㻝㻙㻜㻚㻡㻟㻞㻙㻜㻚㻝㻠㻤㻙㻜㻚㻞㻢㻜㻜㻚㻝㻡㻜㻙㻜㻚㻝㻜㻟㻜㻚㻞㻥㻟㻜㻚㻣㻞㻝 㻖㻖㼀㻟㻜㻌㼇㼟㼉㻜㻚㻠㻞㻠㻜㻚㻟㻣㻢㻜㻚㻞㻝㻜㻜㻚㻟㻣㻤㻙㻜㻚㻣㻞㻡㻱㻰㼀㻌㼇㼟㼉㻙㻜㻚㻝㻢㻞㻜㻚㻞㻟㻥㻙㻜㻚㻜㻥㻞㻙㻜㻚㻠㻝㻠㻙㻜㻚㻞㻞㻟㻙㻜㻚㻞㻠㻞㻜㻚㻠㻝㻟㻜㻚㻠㻡㻤㻜㻚㻡㻞㻣㻜㻚㻡㻠㻝㻙㻜㻚㻝㻢㻢㻜㻚㻟㻣㻢㻙㻜㻚㻟㻤㻡㻜㻚㻣㻤㻤 㻖㻖㻙㻜㻚㻝㻜㻡㻯㻡㻜㻌㼇㼐㻮㼉㻙㻜㻚㻞㻟㻜㻙㻜㻚㻟㻠㻝㻜㻚㻟㻠㻥㻙㻜㻚㻠㻞㻝㻙㻜㻚㻟㻣㻝㻙㻜㻚㻟㻣㻜㻙㻜㻚㻡㻠㻥㻜㻚㻜㻟㻡㻜㻚㻞㻞㻥㻙㻜㻚㻟㻠㻠㻜㻚㻞㻞㻝㻜㻚㻟㻠㻢㻯㻤㻜㻌㼇㼐㻮㼉㻜㻚㻞㻥㻢㻙㻜㻚㻢㻞㻟 㻖㻜㻚㻢㻞㻝 㻖㻜㻚㻞㻝㻣㻙㻜㻚㻞㻟㻝㻙㻜㻚㻞㻥㻜㻙㻜㻚㻝㻜㻝㻜㻚㻜㻥㻜㻜㻚㻞㻟㻞㻙㻜㻚㻞㻟㻟㻜㻚㻝㻡㻣㻜㻚㻡㻠㻝㻰㻡㻜㻌㼇㻑㼉㻙㻜㻚㻞㻟㻞㻙㻜㻚㻟㻡㻞㻜㻚㻟㻟㻢㻙㻜㻚㻠㻞㻟㻙㻜㻚㻟㻣㻞㻙㻜㻚㻞㻤㻠㻙㻜㻚㻡㻠㻤㻜㻚㻜㻟㻢㻜㻚㻞㻟㻜㻙㻜㻚㻟㻢㻜㻜㻚㻞㻝㻣㻜㻚㻟㻠㻡㼀㼟㻌㼇㼟㼉㻙㻜㻚㻝㻝㻣㻜㻚㻠㻝㻜㻙㻜㻚㻢㻣㻥 㻖㻙㻜㻚㻝㻥㻣㻜㻚㻞㻡㻠㻙㻜㻚㻠㻢㻣㻜㻚㻞㻥㻟㻙㻜㻚㻝㻟㻝㻙㻜㻚㻞㻜㻥㻜㻚㻜㻞㻡㻜㻚㻟㻥㻜㻙㻜㻚㻢㻞㻠 㻖

In view of overall tendency of the results shown in Tables above, Dim.1 is significantly correlatedwith many objective parameters. In Table 6, Dim.2 and Dim.3 are more significantly correlated withobjective parameters compared to those in Tables 4 and 5. For example, Dim.2 in Table 6 issignificantly correlated with an objective parameter relating to perceived reverberance, which is notcorrelated with Dim.1. This suggests a possibility that the factor for discrimination varies dependingon the extent of the difference between acoustic conditions being presented.
Table 7 shows correlation coefficients between results shown in Tables 1 to 3 and ratios of objective
parameter of impulse response corresponding to the results.
Table 7 – Correlation coefficient between result of answer from subject and ratio of objective
parameter㻿㻼㻸㻌㼇㼐㻮㼉㻭㻙㼢㼍㼘㼡㼑㻌㼇㻙㼉㼀㻞㻜㻌㼇㼟㼉㼀㻟㻜㻌㼇㼟㼉㻱㻰㼀㻌㼇㼟㼉㻯㻡㻜㻌㼇㼐㻮㼉㻯㻤㻜㻌㼇㼐㻮㼉㻰㻡㻜㻌㼇㻑㼉㼀㼟㻌㼇㼟㼉㻸㼍㼞㼓㼑㻌㼍㼞㼑㼍㻜㻚㻢㻟㻝 㻖㻖㻜㻚㻠㻜㻣 㻖㻖㻜㻚㻠㻠㻡 㻖㻖㻜㻚㻜㻡㻜㻙㻜㻚㻡㻝㻢 㻖㻖㻜㻚㻞㻢㻣 㻖㻜㻚㻞㻟㻥㻙㻜㻚㻜㻡㻠㻙㻜㻚㻞㻡㻡 㻖㻹㼑㼐㼕㼡㼙㻌㼍㼞㼑㼍㻜㻚㻣㻢㻡 㻖㻖㻜㻚㻜㻝㻞㻜㻚㻞㻠㻡㻜㻚㻠㻝㻜 㻖㻙㻜㻚㻠㻟㻠 㻖㻖㻙㻜㻚㻝㻜㻢㻜㻚㻜㻜㻟㻿㼙㼍㼘㼘㻌㼍㼞㼑㼍㻖㻖㻙㻜㻚㻟㻥㻢㻙㻜㻚㻞㻟㻣㻙㻜㻚㻞㻞㻢㻙㻜㻚㻞㻜㻡㻜㻚㻝㻤㻡㻙㻜㻚㻜㻜㻤㻙㻜㻚㻟㻤㻟㻖㻖㻙㻜㻚㻠㻤㻢 㻖㻖㻜㻚㻜㻣㻢㻙㻜㻚㻜㻠㻥㻜㻚㻟㻥㻟 㻖㻖

In Large area and Medium area, the answers from subjects are correlated with SPL greatly and alsowith EDT significantly. This suggests the possibility that the subjects made determinations on thebasis of not only the sound level but also perceived reverberance.
In Small area, although the answers are significantly correlated with SPL, the correlation
coefficient value regarding SPL is smaller than those of the other areas. In addition, correlation
coefficient values regarding C 80 and Ts (centre time) are as high as that regarding SPL, which suggests
the possibility that the subjects made determinations on the basis of perceived clarity of sound as well.
Figure 4 planarly illustrates the result of MDS for Large area. In Figure 4, positions 1, 2, 3, which
are relatively near the stage, are plotted in the negative direction, whereas positions on the second floor
10, 11 12, which are relatively far away from the stage, are plotted in the positive direction on theDim.1 axis. Thus, it can be understood that Dim.1 represents the distance from the stage. Positions 2,5, 11, which are on the center axis of the hall, are plotted on the relatively large coordinates on the4587

Dim.3 axis. Thus, it can be understood that Dim.3 represents the centeredness of each seat position.
Meanwhile, since the stimuli presented in this experiment were impulse responses recorded bymonaural microphone, the tendency of the results should be supported by additional experiment
involving stimuli prepared using a dummy head.

Figure 4 – Planar illustration of Result of MDS, Large area
Figure 5 planarly illustrates the result of MDS for Medium area.

Figure 5 – Planar illustration of Result of MDS, Medium area
In Figure 5, Dim.1 exhibits a tendency similar to that of Figure 4, whereas Dim.2 and Dim.3 exhibit
no clear tendency. In Small area, no clear tendency was found even for Dim.1.
3.3 Zoning by cluster analysis
Figure 6 shows the result of classification into respective categories by cluster analysis by Ward'salgorithm.

Figure 6 – Classification of measurement points by cluster analysis

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As to Large area, the measurement points were categorized into symmetrical zones, and thus theanswers from subjects had some regularity. Medium area was broadly categorized into the front, center,and rear zones, so that it can be expected that the subjects answered on the basis of an acoustic factor
relating to the distance from the stage. In contrast, no regularity was found as to zoning of Small area,
which implies that the determination criterion of the subjects was vague.

4. CONCLUSIONSIn this study, subjective evaluation experiment was carried out regarding perception of thedifference in acoustic condition in audience seats in a hall, and as a result, the following findings wereobtained.
x It was clarified that the relationship between the result of M DS obtained from subject's answers
and objective parameters obtained from impulse responses presented as stimuli tends to vary
according to the size of target seat area.
x Dim.1 of MDS is likely to represent the distance between the stage and the seat posit ion.
x Zoning from the view point of only the acoustic condition is effective for Large area and Medium
area, whereas whether the difference can be perceived is unclear for Small area.

REFERENCES
1. ISO3382-1, Acoustics –Measurement of room acoustic parameters- Part 1: Performance spaces, 2009
2. Wilkens H, Beurteilung von raumeindrücken verschiedener hörerplätze mittels kopfbezogener
stereophonie, Proc. 7th ICA, Budapest, 24 S 5, 1971
3. Yamaguchi K, Multivariate analysis of subjective and physical measures of hall acoustics, The Journalof the Acoustical Society of America, 52, 1972
4. Edwards R M, A subjective assessment of concert hall acoustics, Acustica, 39, pp.183-195, 1974
5. Kruskal J B, Muitidimensional scaling by optimizing goodness of fit to a nonmetric hypothesis,
Psychometrika, vol.29, No.1, 1964
6. Ando Y, Architectural acoustics, Springer-Verlag New York, 1998

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