Mixing Audio, 2nd Edition

11

Phase

What is phase?

Phase, in sound theory at least, describes the time relationship between two or more waveforms. Phase is measured in degrees, and can be easily demonstrated using sine waves. A sine wave starts when its cycle starts. This is denoted by 0°. One complete cycle signifies 360° (which is also 0°), half a cycle 180°, a quarter of a cycle 90° and so forth. If one sine wave reaches a quarter of its cycle when a cycle begins on an identical waveform, the two are said to be 90° out of phase (Figure 11.1).

Figure 11.1 Two identical sine waves 90° out of phase with each other.

The degree of phase shift is dependent on the time ...