Oh crap I just realized something....RTi12's are NOT powered towered. They don't even have powered subs. When you said it had 4 7" woofers I was assuming they were seperately powered but they are not!

Of course they're not going to be able to compare to a seperate powered subwoofer, they are passive speakers! The woofers share the same power as the tweeters, so there's no way they are going to come close to doing what a seperately powered subwoofer can do.

You're definitely expecting way too much from a passive speaker...not knocking the speaker, it's just not designed to do what you're expecting.