I watched "2012" on Blu Ray and this is a really good flick from a surround sound perspective. Now for the bass...I'm thinking my current setup is a bit lacking for deep bass. I currently own a PSB Subsonic 5 (not the 5i) which is good down to 32 Hz. I need something that will dig into the low 20s for around $500Cdn. Is this achievable for my budget? How difficult will it be to dial a 2nd sub into my system that would be able to dig deeper? Is this also achievable with a 7.1 receiver opposed to a 7.2 receiver?