every recording is different obv, and the source dictates the treatment. With that said, there are some basic similarities to lav recordings due to the capsule size and the specific usage. The super small capsules are often very dynamic and clip at lower volumes, they often require faster compression attack times than VO recordings, but compression can require kid gloves because compression artifacts show up more quickly with fast attack times. Also, lav placement is typically dictated by looks and clothes more than by the sound, so recordings are often a little further away and more off-axis than a VO record, and they're often resting against the chest. The net effect is generally a much darker sound than would be achieved with ideal placement.
In my experience there are broad categories of lav recordings:
- top-shelf lav recordings:
the lav is recorded with high end gear (lav->wireless->recorder), placed well and exposed to the camera, minimal clothes rustle, gain staged well, and the person on camera is in a controlled acoustic environment. this is the holy grail, and you'll usually only get it from well-run TV studios and greenscreen soundstages.
usually only needs some compression and maybe a hi-pass to get it all the way there.
- well-recorded under the clothes lav recordings:
the lav is recorded with high end gear, placed well under the clothes, minimal clothes rustle, gain staged well, and often outside or in an otherwise compromised acoustic environment.
I tend to try scooping out some low and low mid before boosting gain on lavs, because boosted high end can get pretty crispy sounding. scooping out that chesty part of the recording and then cranking the gain with the compression ends up yielding a more natural high end on most voice recordings, and this is no exception.
lavs buried under too many layers of clothes, and/or placed too far away from the subject's mouth hole.
I'll still scoop lows first, but then i'll experiment with boosting upper mids into a hipass. The location guy probably didn't record much above about 10khz, so use your ears to find the point of diminishing returns with an upper mid boost sweep, and then lowpass right above that to cut out the residual hiss. these won't sound as good no matter what you do, so rule one is "do no harm"