Press Release Back Number(2006)

Development of Soundproofing Assessment System Using " Sound Camera* "
- System enables instant onsite calculation and measurement of soundproof wall effectiveness -

December 14, 2006
Chubu Electric Power Co., Inc.

Chubu Electric has developed a soundproofing assessment system using a "sound camera." The system is the result of collaboration with Kumagai Gumi Co., Ltd. (President: Hiroshi Ota, Head Office: Shinjuku, Tokyo) and Professor Yasuhiro Yamashita, Faculty of Engineering at Shinshu University (President: Atsushi Komiyama, location: Matsumoto, Nagano Prefecture).


The system builds a virtual soundproof wall on the screen of a "sound camera*" previously developed jointly by Chubu Electric and the other parties and instantly predicts the soundproofing effectiveness of an actual soundproofing wall. Developed to take advantage of the sound camera's ability to pick up all sound data at the measurement point, the system is a breakthrough innovation over previous soundproofing assessment techniques.


Earlier soundproofing assessment techniques predicted soundproofing effectiveness by conducting onsite noise surveys and using a large amount of study data, such as noise source position and noise volume, as input to a calculation program. As a result, performing the study and inputting the results have required a great deal of time and work, and furthermore the prediction was not necessarily correct if the study missed any noise sources.


*A sound camera specifies the direction, volume (dB) and frequency (Hz) of the sound, displaying each of these on an image captured by a digital camera. This unprecedented sound imaging device was previously jointly developed and announced by Chubu Electric, Kumagai Gumi Co., Ltd. and Professor Yasuhiro Yamashita of Shinshu University's Faculty of Engineering in 2001. A low-frequency sound camera, which specifies the direction of low-frequency sounds and displays them visually, was subsequently developed and announced in 2005.


The system has the following features.


  • • It requires only virtual soundproof walls on the screen of a sound camera to instantly predict soundproofing effectiveness.
  • • It allows comparative studies of different soundproof wall scenarios because wall size and position settings can easily be changed.
  • • It enables accurate prediction since it picks up all sound data, unlike previous soundproofing assessment techniques.

This system enables users to perform both the onsite noise study and examination of soundproofing in a smooth way.


This system is expected to find more use in soundproofing studies at various types of sites hereafter.



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1. System overview

The recently developed system operates within a sound camera to perform calculations from the sound camera's measurement results.



2. Example of soundproofing assessment

Figure 1 gives an example of predicting effectiveness of a soundproof wall, with the outdoor part of an air conditioning room as the noise source. The system predicts that the virtual soundproof wall shown on the screen (inside the rectangle) will reduce the noise level from 57.0 dB to 50.4 dB. Figure 2 gives an example of taking measurements on the actual soundproof wall. The measured value was 50.2 dB, which closely fits the predicted value.


Fig. 1: Predicted soundproofing effectiveness



Fig. 2: Measured soundproofing effectiveness


3. Development point

In order to predict the soundproofing effectiveness of a soundproof wall correctly, it is important first of all to correctly understand the sound situation before installing the wall. The sound camera is able to correctly find the direction, volume and frequency of sounds reaching the location. It then displays these instantly on the screen. The idea of using the accurate information captured by the sound camera to predict soundproofing effectiveness was the most important point in the development of this system.