You are going to need a powered subwoofer. You run your speaker cables into it, set your filter, then run another set of speaker cables out of it and into your speakers.
Using a sub with no sub out on my amp
I just bought a Rega IO amplifier it has no sub out I'm using the triangle Berea bro two speakers I'm finding this amp is lacking in bass. I got about a $250 budget I want to add a subwoofer but I don't have a sub out how do I go about hooking one up to my amplifier any help would be appreciated