Eh hem!...Subwoofers... What do ya know?

It really is easy, go big or go home! Just get a Wilson Audio Thor's Hammer and call it good. Kidding. Lot's and lot's of good info here. In the end though, one way or another, a compromise must be met. Budget constraints, testing capability, room realities etc. Not all can have the perfect acoustic room. Like Eric mentioned, get what you can, dial it in to what sounds good to your ears and call it good. OR, go all in, have the room tested, do all the treatment, demo locations/subs and take that route. I recently eliminated my sub for my two channel setup. My room constraints wound up creating more problems than I could/want to try to "fix" so I binned it. Being a drummer I like the low end, but at the end of the day, once my ears changed a bit and the low boomy bass I "thought" I liked, was actually a very real negative. Anyway... I compromised and now I'm happy. (for now) haha!

I think everyone is on the right track relating to their own likes . I agree having lots of power to mains is important. My mains are 3 way bi amped . 150w solid state to the 15” woofer and 100wch tube to the horns, tweets. Asking the woofers to reach down to the basement takes away from their clarity . Subs reinforce those very low notes and in this way gives an omnipresent feel to the sound . With my remote on my c46 preamp i can cut the outputs i used to engage the subs . Sound is still beautiful but having that ability from your chair to turn them on and off sure trains you to set them modestly as to only give the full picture nothing more.  Think of the 20th century fox orchestra intro where the last sound is made by a very large drum kind of a whomp powerful yet subtle . Can you hear a sub? Or the room that drum was recorded. The silence between notes is the most beautiful sound. 

"It really is easy, go big or go home!....  I recently eliminated my sub for my two channel setup. My room constraints wound up creating more problems than I could/want to try to "fix" so I binned it"

geof3,

I guess going big didn't quite work out.

My main system is Apogee Duetta Sigs. They don't go down much below 40-50 Hz, so I added a Paradigm 15 Ref Servo sub - sounded good. Then I added a 2nd 15 Ref Servo sub and it sound great!. I have them wired in stereo and positioned as if they were part of the Apogees - in other words - right next to them. Works for me.