Can you AVR300 owners help me with the proper location for the coax connection for a subwoofer? Does the receiver have a line-level "Subwoofer Out" jack? My Axiom subwoofer doesn't seem to be working, and does not have test tones as do the other speakers, when the coax cable is connected to sub output connection (shown as #31, on page E7 of the AVR300 manual). The speaker power is on, and the menu on the AVR300 is set to recognize a sub. Do I have to wire the sub with left and right speaker cables to the AVR300 (even though the speaker is mono)? Many thanks.