Your graph sounds almost exactly like mine. I got a Behringer Feedback Killer and used it as an EQ and it worked a treat! Takes some tweaking and tricks, but it did a lot to flatten out my response.

So that's one way you can consider going...


---- A Woofer in Tweeter's Clothing... M60s, VP150, QS8s, EP350 Onkyo TX-SR702, Denon DVD-3910