Standing Wave

A standing wave is a stationary pattern of nodes (minimum pressure) and antinodes (maximum pressure) formed when sound reflects between parallel surfaces at resonant frequencies. Standing waves cause dramatic variations in bass response across a room, with some positions experiencing boom and others near-silence at the affected frequency. They are most problematic in small rooms where low-frequency room modes are widely spaced in frequency. The first axial standing wave between two parallel walls occurs at f = c/2L, where L is the distance between the walls. Control strategies include non-parallel surface geometry, bass trapping in corners (where pressure is maximum), and room dimension ratios that distribute modes more evenly. Standing waves are a primary concern in recording studios, control rooms, and home theatres.