The following experiments done with very intense sound in an air‐filled, plane‐wave tube are described: (1) progressive distortion of traveling waves of finite amplitude, both tones and noise; (2) saturation, which is the limit set by nonlinear effects on the amplitude (and intensity) of sound that may be transmitted a given distance; (3) interaction of a tone with noise; (4) suppression of sound by sound; and (5) acoustic levitation. Some of the experiments are illustrated by live demonstrations, others by descriptions and reported data. [Work supported by the Office of Naval Research.]