Page 135 - Master Handbook of Acoustics

FIGURE 6-1 Reflection from a point-source sound from a flat surface (incident sound, solid lines;

reflected sound, broken lines). The reflected sound appears to be from a virtual image source.

Sound follows the same rule as light: The angle of incidence is equal to the angle of reflection, as
shown in Fig. 6-2. Geometry reveals that the angle of incidence θ equals the angle of reflection θ .
i
r
Moreover, just as an image in a mirror, the reflected sound acts as though it originated from a virtual
sound image. The virtual source is acoustically located behind the reflecting surface, just as viewing
an image in a mirror. This image source is located the same distance behind the wall as the real
source is in front of the wall. This is the simple case of a single reflecting surface.