phase

The position of a sound wave relative to other sound waves. As a sound wave travels through the air, it compresses and expands air molecules in peaks and troughs, much like an ocean wave. In the Soundbooth waveform display, peaks appear above the center line, troughs appear below. If two channels of a stereo waveform are exactly opposite in phase, they will cancel each other out. More common, however, are slightly out‑of‑phase waves, which have misaligned peaks and troughs, resulting in duller sound. (See also Waveform measurements.)