Intensity vs. Distance Cues

A balloon deflating isn't necessarily perceived as moving farther away.

Likewise, it's possible to change sound intensity without changing the source's distance.

Cues determining whether change is in the intensity of the source or its distance from the observer:

• spectral balance: increased intensity is usually accompanied by increased higher frequency components for closer sounds;
• reverberation:
  1. intensity ratio of direct to reflected sound
  2. time delay between direct and reflected sound decreases with distance from source.