I plan on running by wires for my 4 rears speakers through a conduit to the back wall. Will having them close together cause them to pick up a hum from each other. Will using in-wall wire provide added protection against that?

BTW I plan to us 16 awg wire run about 20ft-25ft

Will having them close together cause them to pick up a hum from each other.
BTW I plan to us 16 awg wire run about 20ft-25ft

Is there a hum in one of the wires that the others might pick up? You can't pick up anything that isn't there.

Wire size guide:
http://www.roger-russell.com/wire/wire.htm

Hum pickup directly from nearby, parallel cable is really only an issue for runs along power cables. Their 60 Hz frequency is the natural source for hum!

Regards,
Terry

Well actually haven't ran the cable yet. But I shouldn't have to worry about running 4 speaker wires side by side as long as there is no power line in the conduit, right?

right