Polk Audio SC85-IPR DIY In-Ceiling and In-Wall Installation Guide - Page 6

Then: Drill a small 1/2" hole in the sheet rock then using a stiff wire or bent coat hanger "feel" for any obstructions. Be sure to check the locations for all the speakers, if you discover that one location won't work and you have to go to an alternate location that may affect where you want to place the others. Once you have determined the locations for your Polk speakers tape the supplied templates to the wall or ceiling. The use a pencil and trace the edge of the template: Drill a small exploratory hole Bend a stiff wire at a right angle Use the wire to "feel" for wires, pipes and obstructions in the wall If you feel an obstruction, wire or pipe with the wire probe, choose another speaker location. Some obstructions could include electrical wiring, drain, hot, and cold water piping. If you feel no obstructions, now you can cut the opening for the speaker. DIY CI Tutorial 6