IsoDim Help Sound attenuation module


This module is used for estimating the effect of sound traps in ventilation ducts.

Type of sound trap

There's four different types of sound traps. In horizontal and vertical sound traps two of the four surfaces in rectangular ducts are insulated.

Duct dimensions

Use the outside dimension of the duct (without insulation).


The list changes as you select type, it is also possible to enter data for a user defines sound trap. Absorption factors at 6 frequencies must be entered.


The calculation method used has some limitations. To be valid the 6 listed conditions must be met.


Results are shown in a graph and a table. Both show the sound attenuation (damping) in dB/m at six different frequencies.