Modale analyse en simulatie van het geluidveld in zendruimten voor het meten van lucht-geluid-isolatie / Modal analysis and simulation of sound fields in test rooms for measurements of sound insulation
article
Repeatability and reproducibility of the sound reduction index R is bad at low frequencies. One of the causes of the problem is, that the loudspeaker position has a significant effect. For sending rooms of institutes at Delft (The Netherlands), Braunschweig (Germany) and Aarhus (Denmark) the sound field at the test object was computed for different loudspeaker positions and compared with the sound field that would be measured in the sending room during different regular tests. The ratio between the strengths of the sound field that is actually measured in the sending room and the field that is perceived by the test specimen appears to depend on loudspeaker position, sending room and frequency band. From the calculation results loudspeaker positions were choosen that give nearly the same ratio for the different frequency bands and sending rooms. The sound fields in the three sending rooms were calculated analytically and with the finite element method. For the irregularly shaped room at Delft only the finite element method could be applied. Also experimental modal analysis near the test specimen in the three rooms was applied.
TNO Identifier
270798
Source
NAG Nederlands akoestisch genootschap journaal(November), pp. 29-37.
Publisher
NAG Nederlands Akoestisch Genootschap
Collation
10 p.
Pages
29-37
Files
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