I have been hired onto a gig which requires running 3-4 lavs, one or each character. Normally, I use omni-directional lavs (Sennheiser ME2) on my subjects so they don't drop when they move their head around, but I was wondering if using omni's on 3-4 people (sometimes inside a regular size room) will be a bad idea, since they might all pick up everyone who is talking. Are cardiods a better option in this scenario?
My personal opinion.
Speaking as a dubbing mixer Id rather receive 4 x tracks with sep mics on them using a mic, such as the omni you suggest) that doesnt "drop" on movement. The picking up of sound from other contributors:-
1) I dont think will be too significant as lavs are by design quite close pickup
2) Not really relevant as Id be mixing on the faders and would drop the faders of mics not being spoken into at any given moment , right down in the mix, maybe even off.
Its ALL in the mix