Standing Wave

An unwanted sound wave pattern that often occurs when the sound wave bounces between two reflective parallel surfaces in a room, and the reflected waves interfere with the initial wave coming from the sound source, in which the combined wavelength of the affected frequency is effectively the length of the room. This creates the audible illusion that the wave is standing still, so the frequency is amplified to an unwanted level in certain parts of the room while nearly absent in others. Standing waves are most common in square or rectangular rooms with parallel surfaces, so acoustic designers try to prevent these waves by installing absorptive materials or introducing other items to offset the parallel surfaces.