Phase cancellation is when there are two mono inputs in recording which can be used to form a stereo track. Microphones must be ‘in phase’ to produce optimal sound recordings. ‘In Phase’ is when all audio waveforms are ‘pushing and pulling’ as one. If however they aren’t in phase (the waveforms don’t align), certain frequencies cancel out when played as a stereo track as input one peaks and input two valleys at the same time – two opposing forces cancelling the other out. If the signals/waveforms peak and valley at the same time, the signal boosts and becomes stronger – enhancing the quality of the audio.
Impedance – a simple circuit is DC – Direct Current. The current doesn’t fluctuate and stays the same. If there are resistors in this circuit, it can change the current but is only effecting an unchanging DC current. In audio, resistance takes effect on an AC circuit – Alternating Current. This is because the audio is transferred through the circuit at varying voltages to represent the waveforms hence making it a little more complicated when resistance comes into play. Aside from resistors, most audio circuits have to deal with capacitance and inductance resisting in the circuit. These resistances are grouped together to make it simpler and is called Impedance.