Makes Sense… But Does It Really Matter?
If you try this approach, keep in mind that time delay induced by digital processors and drum fill placement can greatly affect audibility.
So to really hear the difference and set the proper polarity, bypass all drum fill and kick channel EQ, and then bring up the kick in the drum fill to the point where it is just on the verge of feedback.
Now, by pressing the phase reverse on the kick channel, you should be able to determine which way is noticeably more stable.
OK, Did That. Now What?
If you did this right and have found a clearly better sounding kick polarity, use it as a starting point to set polarity for the rest of the drum kit.
Working around the rest of the kit, for every mic for the under side of a drum, set the phase the same as you did for the kick. And for every mic for the top or “stick side” of a drum, set the polarity the opposite of how the kick is set. Keep in mind that this is a starting point — upward facing monitors near a floor tom tend to be more stable with the opposite polarity than this approach dictates.
Polarity is another tool that you can use to achieve the sound you’re seeking. There is no “right” or “wrong” way but having a method for quickly finding a consistent starting point can help take some of the voodoo out of a system.
What About The Cymbals?
Polarity issues are going to have the most noticeable effect on low frequencies, as well as when two sources are reproducing similar signal are in very close proximity to each other or mixed together.
Higher frequencies and things panned hard left and right in the mains will often sound different, but there will not be a definitive “ better” sounding choice.
How far is too far? I personally take it pretty far, and further, follow this same pattern on my house console as well. Both my kick and snare bottom are reversed polarity (I top mic my toms).
But how much of this you employ, is, of course, up to you. What we’re doing here is establishing a clean stating point for you to make decisions to change polarity on specific channels to achieve desired results.