boy&hisdogs
I'm Awesome
If the amp has speaker level inputs, there is no need for a line output converter then. I would tap into the front speaker wires for the signal though. Now to get the sub in the box, the box in the truck and finish up the wiring...
You forgot "fix the 5 things that go wrong along the way"
What's the reasoning behind choosing the front channel over the back for the sub/amp?