User Guide

Sound System Design Reference Manual
1-7
Effects of Humidity on Sound
Propagation
Contrary to what most people believe, there
is more sound attenuation in dry air than in damp air.
The effect is a complex one, and it is shown in
Figure 1-11. Note that the effect is significant only
at frequencies above 2 kHz. This means that high
frequencies will be attenuated more with distance
than low frequencies will be, and that the attenuation
will be greatest when the relative humidity is 20
percent or less.
Figure 1-11. Absorption of sound in air vs. relative humidity
Figure 1-10. Effect of cross breeze on apparent direction of sound