The Seattle Symphony’s critically acclaimed “untitled” series explores new music in the informal atmosphere of the lobby of Benaroya Hall. Concerts are Fridays at 10pm, and attract a mix of new music fans and concert hall first-timers, intrigued by the event that's more like a nightclub experience than a classical concert. Nathan Chan is assistant principal cellist of the Symphony and a player in the next “untitled” program on Feb. 28th. Here, Chan talks about the rewards and challenges of new music.