• Title/Summary/Keyword: Acoustical measurement

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On the Transmission Loss Measurement System (전달손실계수 측정 시스템에 대하여)

  • Ryu, Yun-Seon;Kim, Yoon-Seok;Callec, Philippe
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.166-171
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    • 2002
  • The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system using 4-microphone impedance tube is proposed, based on the idea calculating the full transfer matrix of the acoustical sample to test. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

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On the Transmission Loss Measurement System (전달손실계수 측정시스템에 대하여)

  • Yunseon RYU;Yoon-Seok KIM;Philippe CALLEC
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.323.1-323
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    • 2002
  • The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system usiong 4-microphone impedance tube is proposed, based on the idea calculating the full transger matrix of the acoustical sample to test. The theoretical backgroung and measurement system are introduced, and finally the measurement results are verified.

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On the Transmission Loss Measurement System(Part II) (전달손실계수 측정 시스템에 대하여(Part II))

  • 김윤석;류윤선
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.658-661
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    • 2003
  • The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system using 4-microphone impedance tube is proposed, based on the idea calculating the full transfer matrix of the acoustical sample to test. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

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Acoustical design for remodeling of the Little theatre in Sejong Performing Arts Center (세종문화회관 소극장 리모델링을 위한 음향설계)

  • Jeon, Jin-Yong;Lee, Pyoung-Jik;Seo, Choon-Ki
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.991-996
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    • 2007
  • The Little theater in Sejong Performing Arts Center is a proscenium theater with 447 seats, which was built in 1978. The remodeling of the theater was decided in 2005 and acoustical design was conducted. Design guidelines were suggested based on the feasibility studies and acoustical measurement results. Target reverberation time was set at 1.2-1.6s with respect to the main performances. For the acoustical design, side balconies were added to increase the level of lateral reflections. Acoustic diffusers were designed and scattering coefficients were measured in a 1:10 reverberation chamber. From the results of computer simulation and a 1:10 scale model measurement, it was indicated that the new space will have RT of 1.2-1.6 s in middle frequencies when fully occupied.

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Acoustic Transmission Loss Measurement of the Exhaust System with TL Tube (TL 튜브를 이용한 소음기의 음향 전달 손실 계측법)

  • 류윤선;김윤석;이성홍
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.770-773
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    • 2004
  • The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the acoustic transmission loss measurement system using 4-microphone TL tube is applied to the exhaust system, which is one of the most important acoustic control parameters in a car, based on the idea calculating the full transfer matrix. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

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Far-Field Sound Field Estimation from Near-Field Sound Field Data Using Boundary Collocation Method ; Decision of Optimum Points of Measurement (경계 배치법(Boundary Collocation Method)에 의한 근거리 음장 자료로부터 원거리 음장의 예측 ; 최적 측정점 개수의 결정)

  • 김원호;윤종락
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.6
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    • pp.31-37
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    • 1999
  • This paper describes the far-field estimation using the near-field measurement data. Measurement in far-field region gives us the acoustical characteristics of the source but in general measurement is made in near-field such as acoustic water tank or anechoic chamber, so far-field acoustical characteristics of the source should be predicted from near-field data. In this case, the number of measurement points in the near field which relates to the accuracy of the predicted field and the amount of data processing, should be optimized. Existing papers say that measurement points is proportional to kL and depends on geometry and directivity of the source. But they do not give us any definite criterion for the required number of measurement points. Boundary Collocation Method which is one of the far-field prediction methods, is analyzed based on Helmholtz integral equation and Green function and it has been found that the number of measurement points is optimized as 0.54kL which is about one half of the existing results.

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