...everything from quiet lip-popping and humming, to guitarists turning their volume knobs up and down on the guitar, quietly rehearsing the part before the actual take, playing with the whammy bar and pickup switches...whispering, tapping their feet and fingers, farting, suppressed sneezes, throat clearing, clicking guitar picks with their fingernails, moving sheet music and lyrics around, turning on a music stand light switch, pulling lint and fuzz off the condensor mic's windscreen, dropping bottles, chewing gum, eating food.
I have to caution students (I do music clinics, among other things) about playing onstage with mics. I actually do a little segment on playing with microphones, and have an online article on the subject. Even whispers like, "Hey, check out the babe in the front row with the big hooters" will come out over a PA system for all to hear. Rustling sheet music, pencils dropped on music stands, etc. It all comes over the mic.
. As a person that does this for a living, I'm use to all the anomalous stuff in there. The headphone bleed into a mic during vocal takes is pretty standard. Many artists only use one side of the headphones to monitor the part, the other side is left swinging wide open so the vocal mic picks it up.
It really is pretty amazing what can actually be buried down in the mix. I've had everything from quiet lip-popping and humming, to guitarists turning their volume knobs up and down on the guitar, quietly rehearsing the part before the actual take, playing with the whammy bar and pickup switches. I've heard people whispering, tapping their feet and fingers, farting, suppressed sneezes, throat clearing, clicking guitar picks with their fingernails, moving sheet music and lyrics around, turning on a music stand light switch, pulling lint and fuzz off the condensor mic's windscreen, dropping bottles, chewing gum, eating food.
I even had one once where the engineer accidentally left a studio mic open during the mixdown. The board input wasn't being monitored, only the playback. You could just make out a full conversation between band members throughout the entire album. So, I had them submit another mix (without an open studio mic).
. . Falcon
When I was running a lot of theater systems, wireless body mics were a blessing and a curse- if you didn't mute it when they went offstage, you got a lot of crap. If they shut it off during costume changes, then turned it on AFTER you'd brought it up in the mix- ka-BOOM! I'd sometimes record the dress rehearsals to multitrack- each mic getting a channel, if possible, it would help me to analyze which mics worked best for each scene/singer/whatever. This meant that even if I shut off a body mic in the house mix, it would stay on & record to tape. We learned a LOT about the actor's true feelings for all the other people involved in the productions:yes::nono::scratch2:.
And in the case of the Beatles -- especially post SPLHCB Beatles -- you can hear almost all of it on myriad bootlegs. They got to the point where it seemed they recorded everything for, uh, posterity. :scratch2: