Researcher designing study for analyzing speech/movement during interpersonal interaction, need help with proper equipment and setup

Question

Really would like the advice of all the experts out there.

I'm a university researcher interested in interpersonal interaction during conversation. One of the things I would like to do is extract speech from conversational partners along separate channels, and with as little interference from the other partner. I'll then use a program like Praat or Audacity to pull out various acoustic properties of speech - specific to each person. I'll also be recording these conversations with multiple camcorders (which I need to synchronize to do frame-by-frame analysis of movement dynamics).

What I'm thinking of doing is attaching lavalier mics to each person (who will be about 4-6 feet from each other) and then feeding these into a mini audio mixer of some sort to keep separate channels and then relaying that to one of the camcorders (but would prefer to send it to all camcorders simultaneously). My worry is that I'm going to get a lot of interference in each channel from the other person, as well as a great deal of background white noise, particularly if I buy one of the more inexpensive mixers out there.

My question is whether this all makes sense, and what specific types of equipment should I purchase to maximize the clarity of the separate audio channels? Also, is there a mixer out there would allow me to send the output to multiple camcorders simultaneously?

Many thanks, from a novice.

Answer 1

LAVs should be pretty good as long as you get them directional. They will still have some of the other sound, but should have a minimum of background noise. Depending on the quality level you need, bone conduction will provide the best isolation, but also doesn't have as clear of a quality since it is partially synthesized from the vibrations and is a bit more difficult to use. Another option is to get hyperdirectional shotgun mics (the kind with a parabolic dish), but these would require operators to keep it on target while recording.

If you only have two people, you shouldn't need a mixer, you can just run one to the left and one to the right channel and be done with it. You might need a pack to provide phantom power to the mics though depending on what kind of mic you use.