John Spradley's discussion of his "diplacusis" reminded me of an
experience recounted by my brother-in-law, who regularly played in a
jazz band back in the '70s.  At the time, he played keyboard "by ear",
having had no formal training.  One week he had a rather serious ear
infection, and the doctor packed his ear with gauze, etc.  The aural
result was that one ear perceived the pitch a full semitone higher
than the other!  Wow, that must have been quite a weekend for both
the band and the audience!

I've often wondered how uniformly we perceive pitch, anyway.
Do I perceive a given pitch the same as everyone else? What if both
my ears are uniformly different than yours?

By the way, "diplacusis" can be artificially and temporarily
stimulated, such as the study at
http://www.mmk.ei.tum.de/persons/ter/ref/Brink1965a.html

Todd Augsburger - Roller Organs
http://www.rollerorgans.com/