I spent some quality time talking to a real, working, audio engineer about my upcoming video shoot. Here's what he told me about microphone technique. Here's how I'll proceed....

Here's the situation: We're scheduled for a video project that requires us to videograph three people interviewing each other in a very large, bright room that has very high ceilings and hard floors. My first impulse was to use lavaliere microphones (either wired or wireless, no difference to me...) and run two of the channels into one "A" camera and the third microphone output into a "B" camera. That would require two of us to monitor audio levels while operating the cameras. That would also create three different sound tracks, two of which would require syncing in post production editing.

My audio expert works on huge stages and with multiple actors all the time; every day. Years and years.  Keeping track of up to 40 actors, all wearing lavaliere microphones and set to independent channels, in many live shows. When he offers advice about audio I listen.

His suggestion was that I get the interviewees grouped fairly close together for my spot and then mic them with two shotgun microphones. He suggested that there is a sweet spot that's just far enough back to allow two mics to overlap their pickup patterns to effectively cover all three actors.

I asked about using lavalieres for this and he educated me about possible phase issues that could arise and be a bear to fix in post. Better, in his opinion, to stick with a two channel only option and perfect that. Another suggestion (for dealing with the live-ness of the room) was to put sound blankets under the chairs, on the floor behind the chairs and on the floor in front of the chairs. While I won't have each interviewee on a discrete channel I would dodge the dreaded affects of phase issues and also issues of people touching their microphones or having clothing rustle ruin a great quote.

I think that he and I  mostly agree that while well placed lavalieres do a great job at giving one super clean audio and good isolation they can sound quite flat. Think "low dynamic" range, but in audio. A really good shotgun microphone gives a more convincing combination of voice and room tone and, if the actors are a set up linearly then you get actual left to right stereo effect wherein the audio has spatial cues.

One of the other reasons to use wired shotgun microphones is their very low latency effect. Especially versus the newer, mid priced "auto frequency scan" wireless systems. These introduce a bit of delay that can become noticeable as frame rates go up. Wired mics are not affected at anywhere near the same degree.

I'm planning on using two Rode NTG4+ microphones grouped at the end of a Gitzo boom pole, just out of frame. I run them into a passive Beachtek mixer/interface so I can have physical knobs to turn if I want to pull down one channel or the other. Now the only other big thing I need to keep in mind for audio is to bring enough XLR cabling.....

Listening to professionals in the field (at the tops of their games) sure beats the hell out of sourcing information on the gear blogs on the web. And, yes, I get the irony of having just written that.....