[Al Skierkiewicz]

Jonathon,
There is no real way to counteract the phasing you are experiencing other than riding the mics. The phasing is occurring simply by the length of time sounds takes to travel. So as one person speaks, his voice is picked up by the closest mic first and then the next closest, etc. Since all the mic signals are mixed together you are hearing four different signals slightly out of time alignment with each other. At audio frequencies, these slight time differences convert the mixed signal into a comb filter(s). As with any notch filter, phase changes rapidly going into and out of the notch frequency and that is what you hear. The depth of the notch(es) is determined by the level of each of the contributing sources and the frequency is determined by the acoustic distance between the mics. Two mics at equal level can add in phase to only +6dB but out of phase can add to an infinite depth notch. (i.e. >85dB) If you need any further info, please PM me. I am a broadcast maintenance engineer for WTTW/Chicago with specialty in audio.