I downloaded Perfect Pitch, and tried to use it to tune my banjo cumbus. Yes, I was able to get the instrument in tune, but Perfect Pitch was really a little too perfect for my purposes. The pitch of a note played on an acoustic instrument is not constant, so the ear is a better judge of tuning than this very exacting bit of software. If your instrument is electronic, and entirely without vibrato, Perfect Pitch will read its tones perfectly -- but then, if that is the case, you don't need a tuner.