As a sax player, one of the things you get taught is "You play in tune. The sax doesn't".
And this is quite correct. Most saxes will get near to a note, but you basically have to adjust the pitch yourself to fine tune it. This comes with practice.
So. If we assume that I have to play in *perfect* pitch, I go on stage (with a directional microphone and oscilloscope or a digital tuner) and take extra care with every single note. The audience, who would all have directional microphones and oscilloscopes, would obviously be paying special attention.
Of course, we'd have to take atmospheric pressure into account, tuning, say, the drum kit up and down for difference in sea level. And better not use Gibson guitars, because, Fact Fans, the 24 3/4 scale on most Gibsons is fretted up incorrectly, so you get minor intonation errors.
I'd expect nothing less than my picky fans to play our music on vinyl, heaven forfend that their record deck didn't revolve at precisely 33.333 recurring RPM, otherwise that'd put the pitch out, too.
Edited by Davesax1965 - July 16 2015 at 07:14