Acoustics: Sound Fields, Transducers and Vibration, 2nd Edition

13.6. Reflection of a point source from a plane

Here we consider what happens when a point source is placed near an infinite reflective planar boundary. Essentially, a hard reflecting surface is the acoustic equivalent to a mirror in optics whereby each reflecting element on its surface acts as a light source. A mirror can be regarded as a perfect hologram because it produces an intensity that varies with direction in accordance with the law of reflection. That is, the angle of reflection is equal to the angle of incidence. Hence, when you walk past a mirror, the view changes, whereas when you walk past a picture or video screen, it does not. This is because the latter provides only intensity information and no directional information. The ...