Also, the bass with HE-500 through Emotiva, while great also at times comes off non-cohesive. Similarly to the lacking center stage and vocals somewhat going to the left and right towards my ear rather than being in the center or close to it; the bass also feels as if its punching on the sides of my ear and not quite connecting with the bass through the entire width. Typically, the bass is supposed to be through and through, filling the stage. With HE-500 and Emotiva, you can feel the bass hit from the sides and coming near the middle but just not reaching it. So it feels as if you have two separate bass channels kicking separately rather than being unified. With O2, HE-500's bass didn't have this problem. The LCD-2 and other speakers doesn't have this problem either with Emotiva.
I think this might be because the Emotiva pushes the HE-500 to its limit. While it does show a lot more stengths like a wider soundstage, better separation, more controlled and faster bass. It does also amplifies it's few caveats, in this case it's the center stage. Although the height never changed for me with any amp: Fiio E10, O2 or Emotiva. Also, with both E10 and O2, the HE-500's centerstage seems quite sufficient, but again none of them are as wide as Emotiva.