Skip to content

"General" tab

The following options are available:

Air Absorption

Here, the temperature (in °C) and the relative humidity (in %) for the calculation of the air absorption (according to ISO 9613-1) are specified. The default values are 20°C and 60%.

Reference Time

Possibility to enter a user defined reference time in minutes used for the calculation of the operating time correction (see Common Input Data - Sources „Option Operating time (min)“). Default value is 8h. The reference time is also applied for the calculation of the noise dose (see Dosimeter (local))

Frequency Range

Select the lower and upper limits of the frequency range considered in the calculation.

Note

The frequency range is relevant when analyzing the echograms with respect to the room acoustical parameters (see „RIR-Evaluation“ tab below). For example, in order to evaluate the Speech Transmission Index STI a frequency range of at least 125 Hz to 8000 Hz is required.

Grid Interpolation

This option is available for all calculation methods, except for the particle model.

When this option is selected with setting n*n, the calculation will only be performed at every (n+1)th point of the grid points as defined on menu Grid|Properties, plus at the centre of each rectangle defined by these four points. If one of the following conditions is not fulfilled for a rectangle defined by four calculated points, this rectangle will be subdivided into four rectangles of equal size. Then, the same calculation is executed once more for each of these four rectangles. If one of the conditions is still not fulfilled, a further subdivision occurs recursively until the condition finally is fulfilled or until all points the grid properties are considered in the calculation. The conditions are:

  • Max. Difference Corners (dB): The difference between the highest and the lowest level at the four corner points is at most equal to the given maximum (default value: 10 dB).
  • Max. Difference Center (dB): The average of the levels calculated for both points of a diagonal differs from the level calculated for the centre point only by this maximum difference (default value: 0.1 dB). This condition must be met for both diagonals.

If these conditions are fulfilled, the interpolated values agree with the actual values to a reasonable extend. Now, the levels at the remaining grid points within the rectangle are determined from the levels calculated for the four corner points by linear interpolation.

Virtual Acoustic Camera

The immission directivities at receivers can be visualized using the virtual acoustic camera, see Calculate Virtual Acoustic Camera. The resolution can be set with the angular step size to 5 Degree (default) and 3 Degree. The option „include if possible“ (default: off) allows to include the calculation of the virtual acoustic camera when using other calculation functions, e.g. the calculation of receivers, grids or voxel grids. For the explicit function to exclusively trigger the calculation of the virtual acoustic camera, see Calculate Virtual Acoustic Camera.