First, the amplitude can be defined as loudness.
Second, the frequency can be defined as the pitch.
Amplitude and frequency are quite easy. And then what is a phase? Phase can be defined as location or position. There is a sine wave. The highest positive point is called 'Crest' and the lowest negative point is called 'Trough'.
If two oscillators have the same frequency and no phase difference are said to be 'In phase'. The amplitude will be doubled when we mixed together. If two oscillators have the same frequency and different phases are said to be 'Phase Shift'.
The amount of phase can be expressed in degrees from 0 to 360.
If two oscillators are perfectly in phase, the amplitude will be doubled. If the phase shift of one wave is 180 degrees, we can say two oscillators are completely out of phase. And we can’t hear any sound when mixed together. We called phase cancellation.
In digital, 1 is maximum without clipping noise. 0.5 is a half and 0 is nothing. How about -1? -1 is reversed. I mean, the phase shift is 180 degrees. Let's see in Max/MSP.
So we can see the phase cancellation.
