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Acoustic within "eigenmodes of a room"
Posted 12 mai 2020, 12:45 UTC−4 Acoustics & Vibrations Version 5.5 0 Replies
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Hi,
I need some help in comsol.
I am working in the default project "eigenmodes_of_room" and created an additional "normal velocity" boundary with 0.1 inward velocity. Then i added an "impedance" boundary, set the "impedance model" to Absorption Coefficient and set the Absorption Coefficient of the ceiling and walls to 1 to simulate a non-reflective boundary. In the end i added a study 2 frequency domain.
Here my questions, i guess rather understanding-the-program-better-questions:
- Since the sound pressure level plot in the results shows me dB-values from ca. 50 to ca. 120; what is the exact velocity of the initial sound wave? Is it 120 dB at all frequencies? 
- How can I exchange the "normal velocity" boundary with a "plane wave radiation"/"spherical wave radiation" boundary? Im getting no results when Im doing this. 
- Is it possible to configure the initial sound wave (normal velocity boundary) to for example 50 Hz with 80dB, 200 Hz with 74dB, 500 Hz with 83 dB etc? So a specific loudness for every single frequency? 
- Since I can define the impedance of specific boundaries - How is it possible to assign a material on a boundary (wall in the model) which has specific material properties, e.g. the absorption coefficient at 1000Hz = x, etc? 
Best,
Adrian
Hello Adrian Heinisch
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