I've never been a fan of subs because I just couldn't really get them to sound right / integrate the way I wanted, until, I placed an SVS PB13 Ultra directly behind my listening seat pointed at my back. Omg, listening became a visceral experience. It sounded amazing. I bet the 4 sub setup sounds good too. I forgot what it was called. But basically get 4 subs and place them in all different spots to smooth out nulls and peaks and to gain headroom.