Abstract: A musical instrument, for example a flute, whose hole locations are a compromise in order to produce all notes of a scale, has note-identification switches on the keys, whose combination identifies each note selected by the player. A data storage memory responds by outputting a fine-tuning signal specifying a predetermined amount of frequency-tuning bias appropriate for the selected note. A tuning device responds to the tuning signal by automatically and rapidly tuning the instrument differently as each note is played. The tuning device can be a plug in the end of the flute, moved by a motor in response to each tuning signal to bias the frequency slightly as notes are played. The player maintains complete control of pitch, volume, vibrato, etc. When in "calibrate" mode, the notes of a scale are played, the calibrator automatically compares each with the frequencies of an accurate reference scale, and stores the necessary fine-tuning data note-by-note.