Critical Distance Calculator

Calculate critical distance from room volume, reverberation time, and directivity. Free acoustics calculator for speaker and mic placement.

How the critical distance calculator works

Input room dimensions, T60, average absorption, and source directivity Q. The calculator derives room volume and total surface area, then estimates room constant R and critical distance rc where direct and reverberant energy are comparable.

Key terms

  • Critical distance (rc) - beyond this point, reverberation dominates over direct sound.
  • Room constant (R) - Sabine measure of how strongly a room absorbs reflections.
  • Directivity (Q) - 1 omnidirectional, 2 on a boundary, higher in corners or with horn coverage.

Frequently asked questions

  • Why does critical distance matter? Inside rc the direct sound dominates; beyond it, room reflections shape timbre and microphone pickup.