Bilbo,
First, unplug the coaxial sub cable from the Axiom sub and connect one of your CD or DVD player's analog left or right channel line-level audio outputs (RCA jacks) to the line-level input on the sub. Now play any CD with some bass and turn up the Axiom sub's volume control. If the sub is working properly, you should hear muffled-sounding low-frequency sounds of the deep bass energy.
If you don't hear anything, call the Axiom toll-free number.
If the sub works fine, then check your receiver bass management setup menu and make sure you have the Sub turned "ON" and increase the sub (LFE) channel output on the receiver to a healthy 0-dB level or higher until you get output from the Axio sub. Make sure your re-connect the coaxial sub cable from your receiver to the Axiom's line-level input jack.
Set the receiver bass management crossover to 80 Hz and the sub's crossover control to Bypass or its maximum position to remove it from the circuit.
