Jon always seems to be in very good shape vocally in the studio (yes, even on "Burning Bridges"), but in concert he's just awful nowadays.

On the studio recordings his voice is always fresh, powerful (well, at least a lot stronger than live) and clear. The nasal sound is there sometimes, but it's not nearly as prominent (or annoying) as live. In the studio Jon even uses his good ol' rasp pretty often, but always dodges it completely on stage.

My question is this: how is it possible for Jon to sound great on every album, but not live? Is it auto tune, the possibility to record many takes of a song, that Jon always happens to have his "good days" while recording an album, his will to show off on the record, or all these things?