Connect all speakers to amplifier/receiver & set up as
"SMALL" speakers in bass management menu. Select
subwoofer on or "bass out" to "SUBWOOFER"
not "MAIN" or "BOTH".
Connect the subwoofer output on AV amp/receiver to the left
low level input on subwoofer using a commercially available
low level cable.
Set crossover on subwoofer to maximum as the AV amp will
send all relevant frequencies from speakers and LFE to the
sub out jack.