Can You Hang a Lav Mic?
I'm a little late on this one (Dave posted it last week), but it's still a good video and worth noting. This time Knoptop takes Quick FX in an audio direction, testing the theory that you can hang an inexpensive lav mic and get better sound than the normal position on clothing. He gets this from the stage, where actors typically get the ol' "mic on the forehead" trick which Dave sort of replicates here.
It's an interesting experiment, but I think this proves that below the mouth is still the best position for a lav. Actually, I think it sounds better mostly because it's closer to the mouth than the hung version. Even when hidden under the hairline, the mic has less distance to the mouth then when suspended just above the frame. That's one "secret" of good audio. Get the mic as close to the speaker's mouth as possible, no matter where the mic may be.