Standing Waves
Definition
Resonance patterns that occur when sound waves reflect between parallel surfaces in a room and reinforce or cancel at specific frequencies determined by the room dimensions. Standing waves create areas of extreme bass buildup and complete bass cancellation at fixed positions in the room.
In Simple Terms
Bass problems caused by your room's shape. Sound bounces between walls, and at certain frequencies the bouncing waves stack up and get way too loud — or cancel out and disappear. That's why bass sounds completely different depending on where you sit in the room. Bass traps help fix this.
In Practice
A mixing room with parallel walls 4 meters apart produces a standing wave at 43 Hz. At the wall, the bass at that frequency is 12 dB louder than average; at the room's center, it nearly disappears. The engineer places bass traps in the corners and avoids mixing at the exact center of the room.