Standing Wave Calculator — Room Modes

Standing waves occur when sound reflects between parallel surfaces and the reflected wave reinforces the original. This happens when the distance between surfaces is a whole number multiple of half the wavelength. The result is areas of high and low pressure (nodes and antinodes) at fixed positions in the room.

Bass traps in room corners are the most effective treatment. Corner-mounted traps work on modes in all three axes. Membrane absorbers and Helmholtz resonators can target specific problematic frequencies. Moving the listening position away from walls and room centre also helps.

Axial modes occur between two parallel surfaces and are the strongest. Tangential modes involve four surfaces and are about 3 dB weaker. Oblique modes involve all six surfaces and are about 6 dB weaker. This calculator shows axial modes only, as they are the most problematic.