If you like how your system sounds in general, then dual subs should make a nice improvement without changing the character of your system.
There is also something to be said that maybe one Statium III might be better than two Stratus III, ie, upgrade instead of having two. The Stratus is a nice sub in its class, but the Stadium is a nice step up..
There is also something to be said that maybe one Statium III might be better than two Stratus III, ie, upgrade instead of having two. The Stratus is a nice sub in its class, but the Stadium is a nice step up..