As I understand it, the formant is the difference between the interval from the harmonic series, and the interval using whatever temperment you're in. Piano-no

As I understand it, the formant is the difference between the interval from the harmonic series, and the interval using whatever temperment you're in. Piano-notes are in equal temperment. String players, and some wind instruments allow you to play the "in-between" notes selectively (like a true major third, unlike the horrid thing a equal temperment produces) giving you a powerful emotional tool