Late Hamilton College professor Samuel Pellman contributed to Tower of Voices 9/11 memorial in Shanksville

The chimes are eight-inch-diameter tubes cut to somewhere between 5 and 10 feet in length. The length determines the chime’s pitch, but each chime sounds with overtones and undertones, Murdoch said. The goal was to create pitches that would sound distinct, despite those tones, and that would ring in harmony, symbolizing the actions of crew and passengers on that fateful day, but also with a degree of dissonance, reflecting the tragedy, he said.