Standing Wave

The physics behind room modes: a wave reinforcing itself between parallel walls.

When a wavelength fits the distance between two parallel surfaces in whole half-wave multiples, the reflected wave overlays the incident one and “stands”: fixed pressure peaks (antinodes) at boundaries, nulls at odd fractions of the span. First-order modes are the strongest; their frequencies compute directly from the drawn dimension (f ≈ 565/L in feet).