Is that directly from your MDAC or ultimately though your SPL auditor? I don't think the MDAC has enough power to drive the HD800 efficiently and I'm sure the SPL auditor adds to the dynamic of what you hear at the end of the day. If you read on the"Pink Fish Media" forums, most of the people that like V.09 are speaker listeners. I found easy to drive headphones like my COP's sound flat and thin on the V.09.
I'm sure it will differ from person to person depending on what they experience with all the different gear they use.