Tod Machover: composer's social media symphony for Toronto 12 March 2013 Last updated at 00:20 Help Imagine collaborating with a classical composer to create a symphony about your hometown. The people of Toronto, Canada, have done exactly that. On Saturday 9 March, residents were treated to a ground-breaking concert that was the result of an almost year-long project. Sounds recorded by volunteers across the city - everything from noisy traffic to children's voices - were weaved together with the strings and horns of a traditional orchestra. Contributions were invited via the internet and the audience were even able to manipulate the ending of the music via an app. Composer Tod Machover, who is also a technologist at the Massachusetts Institute of Technology, and Peter Oundjian, the music director at the Toronto Symphony Orchestra, explain how the innovative idea worked.