Abbingdon Music Research Reference Class Proffessional Monitor LS-77 User Manual
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wave. Or one whole wavelength - or 1½, 2, 2½ and so on. This phenomenon is called standing waves. Actually
the sound wave is not standing. But it is experienced like that because the sound pressure maxima and minima
are positioned in fixed places in the room.
G 6 Room modes
These special frequencies are also called room modes. Standing waves between parallel walls are called axial
modes. Other modes exist. For instance tangential and radial modes. Normally the axial modes are the strongest.
The standing waves are characterized by having a maximum sound pressure at the boundaries of the room.
Depending on the frequency there are one or more dips across the room. In a box shaped room the frequencies
can be calculated as follows:
Where:
f = frequency in Hz; c = speed of sound (approx. 340 m/s or 1130 ft/s); l = length of the room;
b = width of the room; h = height of the room; n = integer from 0 and up