I'd sure add it and try to keep the crossover very low on both to avoid localization. I think 80Hz is for the birds...and tiny little main speakers. Yours are not tiny. Good luck; I think it can be integrated.
Thoughts on having 2 different sized subs in same room
We are currently in the process of redoing our living room and "Managment", or should I say my, wife does not want any funiture in the design that will provide a place for my equipment. Luckily I still have my main system in my man cave / media room and now since I have an extra sub was considering incorporating into my main system.
Main system breakdown:
Bob Carver Crimson 275 Tube Amp
(80w x2 @ 8 ohms)
Parasound ZPre3 Pre-Amp
U-Turn Orbit TT w/ Ortofon Super OM20
Ifi Zen Phono Pre Amp
Warfedale EVO 4.3 Speakers
SVS SB12-NSD subwoofer
Potential Sub to add:
Audio Source SW15" 200 w Sub
Any thoughts?