Musicians know that a note is not just a note. The fundamental note they play is bolstered by dozens of other tones that thrum above and below it — octaves, fourths, major thirds — in realms we can't quite consciously detect. Just listen to the ringing chords of a piano with the sustain pedal held down: The strings seem to multiply as the harmonics quiver into hearing, auditory ghosts manifesting through... More >>>