I have a friend who just moved into a house and his living room is wired for
surround sound, however, the builders left the wires above the ceiling
(incase you don't want to install surround speakers) and left no clue as to
how to locate them. His house is a townhouse so he apparently doesn't have
access to the attic to go hunting for the wires. My question is, how do you
go about finding the wires? I imagine it's something inductive like a fox
and hound they use in telephone circuits but I haven't found anything that
would work. Anyone have any ideas on how to find them without punching a
hole through the ceiling to go look?

-Bruce