A symphony of bells rang out across the University of Toronto on Friday, celebrating graduation for 1,400 students and nine decades of musical tradition.

The chorus of bells have played out at the downtown campus for the past 90 years. They're the dramatic peals of a carillon, a musical instrument consisting of at least 23 cast bronze bells.

Since 1927, the art of playing the carillon has been passed from one musician to the next. The current honour of U of T carillonneur is held by Roy Lee, who says making the bells sing requires a careful touch.

“They are fully in my control,” he said. “I can feel the instrument, and it is reacting to my touch.”

The massive musical instrument is kept inside the Soldier’s Tower at the university, up 95 steps. Some listeners might assume that the bells are automatic, but Lee says a trained ear can tell the difference.

"If they listen carefully they will know that it's a human up here and not a machine that's playing this," he said.

The university originally acquired the carillon as a way of holding onto a piece of Canadian history.

“They wanted the carillon to be an audio reminder of the sacrifice made by the people in wartime,” said Kathy Parks, a Soldier’s Tower historian with the University of Toronto.

The carillon initially only had the standard 23 bells, all of which were cast in England. An additional 28 bells were added in the 1970s, dramatically expanding the instrument’s musical range

"Now that we have a little over four octaves of bells I can play a lot more music,” Lee said.

The echoing sound reverberates across the downtown campus, adding a sense of grandeur to graduation ceremonies.

"It is a beautiful thing to be part of this and I think it kind of ties the whole thing together,” one student told CTV News.

With a report from CTV’s Peter Akman in Toronto