A bass-baritone who has had a long and successful career (he recorded Alberich for Bernard Haitink between 1989 and 1991), Theo Adam never had a particularly attractive voice. It tends to grittiness and has an intermittent beat which was already apparent by the mid-sixties. He did have a good dramatic sense though, which made him the Wotan of choice at Bayreuth during the sixties, where he recorded the role live on the famous Karl Böhm cycle, with Wolfgang Windgassen and Birgit Nilsson. He was always a reliable singer, and in spite of the flaws in his voice, achieved remarkable vocal longevity: he re-recorded the role of Wotan for Marek Janowski (an under-rated recording of the cycle) in the early eighties, by which time he was in his mid fifties, and there is very little difference in the quality of the voice from the Bayreuth performances recorded nearly twenty years earlier.

Not surprisingly, Adam's roles included quite a lot of not-very-nice people, such as Boris Godunov, Don Pizarro, Don Giovanni and Alberich. He was also a successful Wozzeck.