If you throw a rock in L.A. and you don’t hit a Starbucks, you’ve probably knocked a musician out cold. Guitar slingers are a dime a dozen these days, but quality tunes are scarce. Viral videos and auto tune have taken rock n’ roll hostage, Facebook fans are more important than real fans, and virtual likes carry more weight than a modern track that cuts deep. But hope remains for the future of music. L.A.’s own Steven Roth is knocking on your door, and whether or not you’re listening, you will hear him.