Vienna Acoustics Bach Grand

I'm currently demo'ing a pair of these speakers in my home. It's seeming as if there's a bit of muddiness in the mid-bass. From anybody whose heard these speakers, is this something that could be a function of how much power I'm giving it? I'm using an HK AVR125, rated at 45 w/ch. Highs and midrange seem just fine, in fact it sounds great. Its just when I play something a bit denser, such as Dave Matthews Band or even some of Sting's more recent albums, that I'm finding this type of performance. I don't listen to anything much harder, but if I ever do, I would imagine it would only exacerbate the issue.

I was expecting something a bit more, but wondering if it's the fault of my equipment rather than the speaker. My old speakers were three-way, so I'm wondering if I might need a speaker with a dedicated midrange plus woofer to get me the sound I'm wanting?