Why are you supposed to put one mic out of phase? I dont agree with this at all, actually sounds like a misunderstanding. I assume you mean having a close mic on the beater and one farther back out front. You DO want these in phase if you want it to thump. Out of phase it will not have much impact. You can hear it by moving the mic aroud with some loud headphones on. You can also put it in phase in a DAW editor by sliding it forwards or backwards a few samples, and this is very visible.