[sethgrisham]

Just because an instrument can do equal temperament doesn't mean that is necessarily the best choice. Although absolute pitch can't be heard by most, relative pitch can, and so when playing any interval, such as a fourth, it will sound off in equal temperament, yet sound perfect when you put it "out of tune". There's some pretty interesting music theory that comes out of the traditional 12 tones not being able to be equally subdivided to then be arranged into those perfect intervals