If you went to Florida in November, you missed some magical moments at Symphony Hall. Hot conductor Gustavo Dudamel and his Simon Bolivar Youth Orchestra (pictured at right) wowed the audiences one day, and Boston Symphony Orchestra maestro James Levine kept the crowd spellbound less than 24 hours later. Writing of the BSO's performance of Mahler's Ninth, Globe critic Jeremy Eichler praised the BSO's string section. "The depth and sweetness of tone, the purity of intonation, and Levine's impeccable balancing of the string choir made this movement devastatingly effective," he wrote. "At the very end, you couldn't tell exactly where the music stopped and the silence began. Wherever that point was, Levine held it for a small eternity."