There is a scene where Baby John goes into Regina's room and she's standing on a chair, removing a curtain rod that she wants to use as a weapon. We see her do this twice in rapid succession.
Boom mic visible in upper left corner of frame when Evelyn is knitting and talking to the guests after the first huge dinner.
When the members of the house respond to Regina screaming in the kitchen, the moving shadow of the boom mic is visible behind Evelyn right when she enters.