LoL, you look like my old Machine Shop teacher. Do you ride a motorcycle by any chance? LoL
Are you saying you want to disable the infrasonic filter, or override it or what?
You could find a way to use an equalizer to boost the 20hz range ONLY. Key point is ONLY that range so that when your amp tries to filter it, the input voltage is higher so when it filters it, it's like the filter isn't there.
You get what I'm saying, or no?