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Acoustical measurement in a concert hall 1
system test and 1/10 scale model experiment

Before the construction of Tsuyama City music hall, 1/10 scale model measurement was performed for designing the acoustical materials, such as columns around the wall and ceiling diffuser panels. See this article for more information about the experiment. 

In this report, the results of the scale model measurement will be summarized, and how to analyze the impulse response data will be explained.

This is a photo inside the scale model. Omni-directional speaker was placed on the stage. 
Number of columns are installed inside the hall to increase the diffused reflection from the side walls. This design is inspired from the excellent acoustic environment of forest.
Binaural impulse responses were measured using the MLS (Maximum Length Sequence) signal. TSP (Time Stretched Pulse) signal is also available now. It is much more robust against noise, and very clean impulse response can be obtained.
Measurement date 20 February 1998
Data analysis date 4 June 2003
Measurement place Tsuyama, Japan
Microphone type ACO DH-7046 Condenser Microphone
Microphone size 1/10 dummy head
Microphone amplifier B&K Type 5935
PC Dell Inspiron 3000
OS Windows95
Software DSSF3  
Loudspeaker KENWOOD OMNI-7
Block diagram of the measurement

Scale model: plan view

Measurement was performed for 16 positions in the audience area. System test was done at point 2. 
Scale model: plan view around stage area

SP (* mark) indicates the location of the loudspeaker. It was located on the center of the stage. 

Before the actual measurement, measurement system itself is tested carefully. Speaker check, direct connection check, microphone check, and so. 

This is a test for direct connection of input and output. Impulse response shows no problem. 

In this test, MLS signal was used for left channel and pink noise was used for right channel. 

This is a test for synchronization. 

Below is a main window of the Sound Analyzer. Measured data in the Realtime Analyzer is analyzed later.  

June 2003 by Masatsugu Sakurai

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