Zero Crossing and Crossfades

Zero crossing is the point at which a digital audio wave has zero amplitude. From this point, the signal will either rise or fall in amplitude. When an audio segment is selected on the timeline to be looped or cut and pasted with another segment, its start and end points should be at zero crossing; otherwise, there will be a jump in amplitude at the loop or edit point which will result in an unwanted click or pop. To loop a selection or edit two sections together smoothly, the audio waveform will have to be zoomed in to sample level.