What Axiom subwoofer(s) do you own?
Older EP500 (Build 10123?), upgraded to 1,000 watts. All settings below are for the original EP500.

Where do you have the Level, Frequency, Phase, and Subsonic Filter (if applicable) controls set?
Level: - Max
Freq: 150
Phase: 180
Sub Filter: On

How are you connecting your signal source to the subwoofer (RCA/XLR/High Level)?

What receiver/processor/pre-amp/integrated amplifier are you using?
Denon AVR 2310CI

What are you using for your main speakers?
JBL Studio S31211

Where do you have the crossover frequency and trim levels set in your processor/receiver for your main speakers and your Axiom subwoofer?
Mains: 80Hz
Sub: 80Hz

Are you using the trigger on your subwoofer?
Yes. It operated well until I inadvertently connected the trigger-out line (from the Denon) to the audio processor circuit. (That was an installation problem ... not Axiom). Resulted in upgrading the EP500. Would recommend Axiom consider some sort of breaker system for the audio processor that would sense over voltage and protect your very fine equipment.