I am a violinist. :) That's my primary instrument. But even there you don't tune to perfects fifths all the time. In string quartets you tune the bottom C of th

I am a violinist. :) That's my primary instrument. But even there you don't tune to perfects fifths all the time. In string quartets you tune the bottom C of the cello up a bit and the E's of the violins down a bit. But if you're playing with a piano in, say, a piano quintet, you generally play equal temperament with the piano.