StateDJ85:

Something's not right here...if your speakers are set to small, and the bass is set to SUB only you should be getting a signal...how do you connect the sub? With speaker wire or with a sub cable?
If you're using a sub cable, something is weird here.

In my system, the Parametric eq setup thingy kills my sub's level to minimum, and then sets the distance to 17 feet or so, though it's clearly only 8.5 ft from the mic.
I manually adjust this and everything becomes perfect...suggest you look into this too...you should NOT need to set bass output to fronts + sub to get a signal.
Make sure the sub cable is in the "input" slot on the sub and the output slot of the receiver.