YouTube has selected the musicians for its next symphony orchestra project, which takes place in Sydney this March. Ninety-seven players from more than 30 countries were chosen after submitting video auditions to the site. The musicians, ranging in age from 14 to 49, will spend a week in Australia working with conductor Michael Tilson Thomas before giving a live performance in Sydney Opera House. Four players, including a violinist and an electric double bassist, will get to  perform an improvisation to a piece specially written for the orchestra by Mason Bates.