JSE is a full orchestra playing standard repertoire: overtures, concertos, and symphonies. For many students this is where they do their best playing. A child who spends several years here, performing twice a season in front of a real audience, has had a complete musical education.
Occasionally a JSE player is asked to join the Young Symphonic Ensemble for the Discovery Gala or a tour. That is not a reward for time spent in JSE. It happens when faculty can already hear that a player is at YSE standard and simply has not auditioned yet. If that sounds like your child, the answer is to audition.
If your child wants to go further, the Young Symphonic Ensemble audition runs every semester, whenever they feel ready to handle its requirements. Those requirements are published, so you can read them together and decide when the time is right.
