As the header states, I am looking for the Best Way To Incorporate Infrasonic Filter on Sub. Aka subsonic filter. I want to block lows below 30 hz from getting to my sub (down to where it is rated). I dropped down to a single 18" from dual 18"s that has more than enough output in my room, now I just need to protect it. I am open to software/hardware solutions. Free is a nice plus 😁. I have a crown K2 running the sub and it doesn't have this filter available like some pro amps Do. I use foobar 2000 as my drug of choice. Thanks for the advice.