I am trying to install a cona into a setup with Beolink Passive powering two front RL60.2 and another passive powering two rear S45-2. All connected to Beosytem 1 with a beolab 4000 as center. I am not sure how to put the cona into the set-up 1. Do i need a seperate amp for subwoffer fed from BS1 subwoofer...