Wall
The Wall subnode is available from the context menu (right-click the Room parent node) or from the Physics toolbar, Attributes menu. It is used to define the wall absorption properties.
Wall Absorption Properties
The absorption coefficient properties to define depend on the choice of Band Input Type for The Acoustic Diffusion Equation. The absorption is defined through the random incidence absorption coefficient α (the value is different from the normal incidence absorption typically used in, for example, pressure acoustics).
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If the Band Input Type is Flat (continuous) enter an Absorption coefficient α (dimensionless).
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For Octave bands, 1/3 octave bands, or User defined bands, enter an Absorption coefficient α (dimensionless) in each row corresponding to the Band Number.
Select an Exchange coefficient model — Sabine type (the default), Eyring type, Modified Eyring type, or User defined. For User defined enter an Exchange coefficient h (SI unit: m/s). The choice gives different statistical models which are applicable for different ranges of absorption coefficients. The Sabine type is applicable for α < 0.2 while the two others are valid up to an absorption of 1.
Note that the tables that are imported, using the Load from File button (), will replace the existing data. You can only import a table that has the expected size. The band number column is disregarded when importing. To create a data file to load, it is recommended to save the existing table and then edit and change the values in that file.