What crossovers to use with JL Audio 112 sub?

Hi, am using a JL Audio F112 sub & probably a Bryson 4B-SST2 amp with Mag 3.6's. I want to cut out everything from the Mags above 80. What filters have people had good luck with? Any experience with Marchands? Thanks. Laurence
I've used the Marchand in the past and had success. I now use a Pass Labs XVR1 (pricey), huge flexibility with the Pass, many different slopes to try. I currently use a 24dB roll at 88Hz to my F112. My mains are ML CLS IIz.
The NHT X2 filter if you can find a used one. I believe they have stopped production. Bryston makes the 10B SUB. Hsu Research has a reasonably priced crossover. You could also consider Rane and Ashly.