Nope. Not after I turn the LFE channel up 15dB in my 5.1 to binaural DSP with my modded T50RPs.
I know that because 5.3VRMS just happens to be almost exactly what my O2 puts out right now. It gets a bit louder than I need right now but my T50RPs are probably going to get even less efficient after I get around to trying more aggressive damping schemes so I could use a little more power. When I build the ODA I'm going to make sure it gets the full 7VRMS. I hope I can keep it within the O2's capabilities when combined with my movie EQ
Yeah, 5.3 Vrms may not be enough for you, but it's actually enough to push the DT880 (600 ohms version) to 110 dB peaks. SO I guess that should be enough for most people.