Echo & Reverberation Room (2D)

This top-down 2D simulator sends a sound pulse from a source point inside a rectangular room and traces it as it bounces off all four walls at the real speed of sound, 343 m/s. Resize the room and change the wall absorption coefficient to see how a distant, hard-walled room produces a clean, late echo while a small, absorbent room produces fast, dense reverberation instead — with the reverberation time computed live from the real Sabine formula, RT60 = 0.161·V/A.