Onkyo TX-NR609 with EPIK Legend Woofer Question

[ReggaetonSalsero]

Hi all. Question..... I bought a txnr 609 receiver and i'm about to order a new epik legend sub for it. Right now i have the receiver connected as a 7.0 system without a sub. I saw on the receiver that there is a part that says lpe and it goes from 80hz to up to 120hz then an option to select bypass if i don't want to select 80 to 120hz. How should i set this so that i get good bass sound while i wait for the legend sub? I had it on 120hz then on 80hz but i can't tell what's the difference. Maybe i'm tone deaf.

Then when i get the epik legend sub in, how should i have it? And how should i set it up with the legend when i get it? I know many of u would know. I tried looking this kind of thing up on here but i couldn't find anything on it. Thanks kindly Oh and i have 2 monitor 50's in the front, one cs1 in the center...4 monitor 40's in the back...i have them all set on 80hz front and back. I don't know what to do with the crossover/lpe part in the receiver. Should i go 80hz, 90hz, 100hz 120 hz or bypass?