How does the station Bravo keep people addicted to its reality TV shows? A composer says that he and others make the station sound like candy: “midcentury spy film vibraphones. Tchaikovskian pizzicato — that is, finger-plucked — violin strings. The melodious wooden tock-tock-tock of a struck marimba. Egg shakers. Cymbals which, when struck in succession, vibrate with an ephemeral sound halfway between a wish and a sparkle.”