Klipsch R-115sw and high pass filters

I just bought this from Emile off the Klipsch fourm. Great sub. And Emile , like always, treated me very well in this deal.
What I’d like to do is install a high pass filter before the amp, maybe 15hz. So I can help it live a happy and healthy life without sending stuff into the amp that it can’t handle. I don’t really want to use a dsp. I do have a few of the none HD 2x4 Dayton dsp units. I will if I have to. But really want it to be a set and forget and no power to worry about.
So I guess I need a passive crossover for this. My denon does not have anything in the setup for the sub outs for doing this. Just a regular crossover points for the low pass and high pass for the other speakers. You’d thing they would start to add this into HT receivers?