Correct -- as everyone says, NEVER wind the lav cable tightly or put long-term stress on it ... whether for storage or use.
When the actors get used to putting on their own mics, we
hand them the entire plastic case (with batteries already checked, transmitter turned on and already in polybag), and we read them the riot act about tugging or kinking the
cord or wrapping it around the transmitter. They are supposed to bring it back looking like that picture ... coil loosely wound and resting on top of or above transmitter in the box. (So having individual containers for each mic
unit is definitely helpful.) The condition they ACTUALLY come back in every night is of course all over the map, so we usually have to straighten and re-wrap the lavs each night before putting them away. Some actors "get it" more than others ... you can definitely tell who the slobs are!
Back to bending the
cord, the pros I have seen will take up slack by bunching the cable pretty tightly like how
power cords are commonly wrapped with a twisty in the middle of the bundle -- except that a hellerman sleeve is used to hold the wrap together. Hellerman sleeve will hold for the duration of the production, and therefore desirable over tape (and don't leave sticky residue. They also put a looback just above the
connector for
strain relief, also held with a hellerman sleeve. If I ever do this I'll take pics to post.
So I don't think a tight curve on the cable is a huge issue -- just don't kink it. If you were to ask for a rule of thumb on actual curvature, for single bends I'd say don't
bend the cable tighter than the curvature of your pinky finger, and for coiling use four fingers of one
hand. At least that what I'm seeing.
-- John