Room Modes App
The Room Modes Application calculates the modal response of a room at the lowest frequencies where the modal situation is dominate.
This program is unique from all others (that I know of) in that it uses complex modes. (In reality all rooms with sound absorption have complex modes.)
Complex modes are fundamentally different than real modes in several ways. First, only if the modes and the entire set of calculations are complex can there be any
real energy flow in the room as would be required if there was localized sound absorption. In most modal programs the "damping" is added to
the summation as a singular damping term - a global complex terms that attempts to account for the sound absorption. With this form of damping the sound is
absorbed equally and continuosly throughout the space as would happen if the absorption were entirely air absorption. This is, of course, not the case
since at low frequencies virtually all sound
absorption takes place at the walls. If the damping is small then these differences in the two approaches are minimal. But for larger wall absorption
- particularly when it is not uniformly applied - the differences can be quite substantial.
In this application the room layout is shown for the X-Y (floorplan) plane and the Y-Z plane. The sources are draged about the room with the mouse as can the listener as well.
Dragging the upper main moves both source symmetrically. Dragging the lower one moves just this main. Both mains must be at the same height. Run Polar Map The application requires .Net 3.5 or later to run. |