Contrary to Popular Belief, Phase and Polarity Are Not the Same Thing
By Jeff Baust
the audio world, you often see the words polarity and phase used interchangeably,
which might lead you to believe that they mean the same thing. However,
these terms refer to two different concepts. Ill look at each concept,
discuss how they relate to one another, and give you some examples that
illustrate them in terms of music production.
Polarity refers to the positive and negative values of a signal voltage. Consider the sine wave in Fig. 1a. This waveform, like all analog audio signals, is an alternating-current (AC) signal, which means that the signal voltage repeatedly alternates from positive to negative. The voltage starts at 0V, goes positive, then negative, then back to 0. This completes 360 degrees of the waveform, or one cycle.
look at the sine wave in Fig. 1b, which is a copy of the first.
The voltage starts at 0, goes negative, then positive, and ends up back
at 0. This waveform is like a mirror image of the original, because its
polarity is reversed, or inverted, with respect to the original. Whenever
the first sine waves voltage values are positive, the second waves
voltages are negative, and vice versa.