Originally Posted by pizzaguy

I've been hiking all day, Dave. Wish I'd seen this sooner.

If you go to the trouble of running four more wires from head to amp, you can actually have four channel sound. The amp is four channels, but they bridge them such that the head's front left and right outputs drive everything.
See this thread:

https://www.crossfireforum.org/forum...-channels.html

If you are not going to do that, then just use front left and front right outputs to drive the four wires going to the amp