Superlatives A Vulture series in which artists judge the best and worst of their own careers. Photo-Illustration: Vulture; Photo: Ian Dickson/Redferns In the early ’90s, Karlheinz Brandenburg was searching for a song with optimal humanity. As the creator of the MP3, his ideal test subject needed to be warm enough to challenge his highly refined compression algorithm. Then, down the hallway from his office in West Germany, he heard the radio playing a track with vocals cool and strong: “I am