Well, yeah, exactly. Hence why I mentioned the possibility of the distortion I've heard myself being due to the version of the tracks on Spotify. As I mentioned, I can hear noticable distortion on some tracks with my aeon's that I didn't notice with dt770's.Not all of the songs on Spotify are perfectly mastered and some of them are probably transcoded from lossy MP3's or something.
It's more likely a combination of spotty encoding and my FiiO. I don't really have time to A/B test at work... Hence positing a theory to encourage discussion.
I'm looking forward to doing all kinds of comparisons this weekend. Pad rolling, checking out various version of songs in my library. Still plenty of cool stuff to uncover with this hobby -- outside of simply enjoying awesome sounding music