Re: outdoor speaker wiring
The PVC conduit is an excellent idea from a protection standpoint but keep in mind that it is in the ground and will fill with water whatever you do. Any buried conduit is considered a wet location. A PVC jacketed cable pulled through it will deteriorate over time.
I normally use type TC cable for this. Type TC is listed for direct burial so this is what you want whether you install it in buried PVC or direct buried by itself. Either way keep it at least 18" down so that landscapers are less apt to encounter it. I have even gone so far as to bury a yellow "caution" tape a couple if inches from the surface when backfilling.
As to wire size, no, 16ga is usually not adequate for any kind of low impedance (8 ohm voice coil) systems like this especially for 140+ feet. I normally do constant voltage systems so wire size (like line voltage lighting vs low voltage lighting) is less of a problem but you will need to use at least 12ga all the way in this application.
The 200 watts(or 100 watts per channel) that the amp is capable of supplying really has no bearing here since the speakers, even if they could handle the 100 or 200 watts, will never be turned up that loud.
What you want to do is to keep the wire resistance in series with the low impedance 8 ohm speakers to an economical minimum so bigger wire is always better. Consider that for 8 ohms worth of wire you lose half your power with one speaker. Since you will be connecting two 8 ohm speakers in parallel only 4 ohms of wire will cost you half your power.
-Hal
[ June 14, 2004, 12:05 AM: Message edited by: hbiss ]