Phase cancellation is often the culprit when an instrument sounds thin and wimpy on a recording. However, you can learn to induce phase issues for creative purposes. In today’s Tech Tip, we’ll show you how phase issues can be intentionally created with mic positioning, resulting in a comb-filtered sound.
Since phase cancellations are caused by the same sound reaching two or more mics at different times, the position of the mics irelative to one another dictates the amount of comb filtering that will occur. This gives you the ability to fine-tune the mic positioning for the desired effect.
For example, if you have a mic sitting up close to the grille cloth, disregard the typical 3:1 ratio placement rule, and try putting the distant mic two feet away from the cabinet. Listen to the summed sound of the two channels, and you will hear that it sounds different than the amp does in the room. This is because the distant mic is capturing the signal later than the close mic, introducing phase cancellations, which result in a comb filter effect. Moving the distant microphone closer to or farther from the source changes the amount and timbre of the comb filtering, giving you the ability to find the interesting sound you’re looking for.