Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in a net reduction in the overall level of the combined signal. If two identical signals are 100% or 180 degrees out of phase they will completely cancel one another if combined. Thi is a simple definition for Phase cancellation.
In real life you will not experience full phase cancellation except if you double a track and reverse the phase. Usually you will experience problems similar to the picture above.
You can easily detect phase problems if the sound in solo is full, meaty, with great low and in combination with other element or with the signal from the second mic recording it sounds shallow, you will simply feel that something is missing. Most of the time the problem is in the low end. The easiest way to detect phase while mixing is with Stereo Analyzer, but to recognize phase issue is important to solve that problem early in the recording phase. (with changing mic placement sometimes just a inch can make a difference.)
We can experience phase cancellation easily in layering different music elements (kick, snare, claps, bass, vocals), bad microphone placement in multi mic recording (not paying attention while recording), Parallel Processing, Mics and direct boxes can be wired out of phase e tc.
5 SIMPLE WAYS TO SOLVE PHASE ISSUES
- Flip the polarity by 180 degrees with the switch on the track – if this doesn’t help. (this helps a lot in drum recordings, especially between snare top and bottom mic.)
- Zoom in the waveforms in which you’ve experienced phase problems and adjust them. If you constantly see that one track is going positive while the other is negative, just slightly nudge one the tracks to line up with the other. Look for transients as good reference points.
- For cases when you’re using parallel processing, and you hear problems when you solo the tracks,you can either add a specialized plugin to delay the original source, or you can simply guess-and-check using the nudge method above.
- Do a Low Cut on the signal that you don’t need the lows and the mid-low. Let’s say if I’ve blended two kicks and I start to hear phase problems in the low end. I will do a low cut on the kick that I’ve decided to use as a punchy in the highs, or you can try in snare recording with top and bottom mic, do a low cut on the bottom mic because we don’t need the low end from the bottom mic if the problem still persist.
- Use Phase Correction Plugin for more complex problems . Like The Waves InPhase plugin
Don’t drive yourself nuts trying to make sure everything is perfect . It simply will not happen with complex waveforms. However, if the issues do crop up, you will now be ready! Thanks for reading!
Watch this video tutorial, it will help you understand even more with this kick and bass example.