High pass filter need

What is the best way to add a high pass filter to my front mains (Dynaudio C-1s) from my Mc intosh pre to McCormack DNA-2 amp. 
A seperate line out from the pre goes to my JL sub which has its own filter. 
I want the cleanest option that will not alter the C1 sound other than remove the lowest octaves they can’t really handle that the sub can. id like to reduce the amp and speaker from trying to work on the low end.