Imagine throwing two pebbles into a calm pool, the expanding concentric ripples collide with each other creating a complex pattern. Now imagine that in three dimensions and in sound, that is what you experience when you hear the “Harmonic Cannon”, now installed at Trinity College of Music. One of this pair of bells sounds the major harmonic series , the other the minor harmonic series a semitone higher. These two series share a couple of frequencies, so when both bells are ringing these frequencies collide and interfere with each other creating complex acoustic patterns. The “Harmonic Cannon” is also a composition device and a number of composers and contemporary musicians are working on pieces at the moment which use the notes and beat patterns of this pair of bells for a performance early next year. It is anticipated that before and after a performance with the bells, the bells will be rolled into the foyer for the audience to play.