Metric Halo Mobile I/O - Manual (Page 361)

Glossary
361
Phase Describes the position of one sound wave relative to another, or in relation
to time. Let's look at phase between two signals. In the first example, the two
signals have the same phase:
Figure 319: 0° Phase Offset
The two signals are drawn perfectly on top of each other. In the next example,
the right signal is 180° out of phase with the left signal. When the audio on
the left is at its highest, the right is at its lowest and vice versa. A signal that
is 180° out of phase is also called “polarity inverted” or “phase inverted”
Figure 320: 180° Phase Offset
If we sum the signals together, we get nothing; the high of the left is cancelled
out by the low of the right. This is called phase cancellation