The sensitivity according to published specs is the same for both speakers so it's surprising that the M80s should sound louder. It's possible the v4 is more sensitive than previous versions and Axiom has not yet updated the specs. It's also possible the two manufacturers measured the sensitivity differently.
Whatever obnoxious I hear in my M80v2 tweeter is in the recording. If the tweeter in the Air is the v4 tweeter, I would say Axiom has softened its response. Either that or the softened response I'm hearing is due to the Air's grill.
