Perceptual Approach to Reverberation Simulation

• Based on perceptual limits, the impulse response of a reverberant space can be divided into two segments:
  • The beginning of the impulse response consists of distinct, relatively sparse, early reflections.
  • The remainder of the impulse response, called the late reverberation, consists of densely-packed echoes that become impossible to distinguish in time.
  • This region of high echo density (which increases as $t^2$) can be approximated by a random time distribution.

• The frequency response of a reverberant space can likewise be divided into two segments:
  • The low-frequency region consists of a relatively sparse distribution of resonant modes.
  • Higher-frequency modes are packed so densely that they are best characterized by a random frequency distribution with certain statistical properties.

• Parametric controls for an artificial reverberator would ideally include:
  • $t_{60}(f)$ in at least three frequency bands
  • $G^2(f)$ = signal power gain
  • $C(f)$ = "clarity" (ratio of impulse response energy in early reflections to that in the late reverb section)
  • inter-aural correlation coefficient at the left and right ears