Reflections

• There are several paths the sound emanating from the source can take before reaching the listener.

• The closest path is the one taken by the direct sound.

• Delayed images reaching the listener lengthen the time the listener hears the sound.

• Recall, the amplitude of the sound decreases at a rate inversely proportional to the distance traveled.
  • sound is not only delayed, but it also decays.
  • reverberation tends to have an (mostly exponentially) decaying amplitude envelope.

• Four physical measurements that effect the character of reverberation (and thus character of the space):
  1. reverb time (RT or T60);
  2. frequency dependence of RT;
  3. time delay between the arrival of the direct sound and the first reflection;
  4. rate at which the echo density builds.