Inside a quaint yellow-and-blue Victorian, set on one of the grittiest of Mission streets, lives a quiet refuge for music. Well, maybe not so quiet: Stand in the hallway of the Community Music Center and you're likely to hear the low hum of a cello, the happy plink of piano keys, or the eerie wail of a violin -- or all three together -- coming from behind closed doors. In addition to offering numerous music classes for kids and adults (not to mention private lessons and summer camp), the Community Center rents private practice rooms, each furnished with an upright Yamaha piano, for $1 per hour. And once you've practiced and practiced, you can rent the full hall and have yourself a recital.