It is distinct from other tenor fächer by its endurance,[8][9] volume,[10][11] and dark timbre, which may be, in its middle register, like that of a baritone.[4][12] The voice may also sound clear or metallic.[1] It is one of the rarest voice types in opera.[13][14] Heldentenor roles, such as the title roles in Siegfried and Lohengrin, often require commanding stage presence and strong acting ability. In some cases, due to reasons such as voice misidentification, singers may begin their careers as baritones before later transitioning.[15][16][17] The term heldentenor may be used to refer to both a singer and their voice.
The treble counterpart of the heldentenor is the Wagnerian soprano.[18][19][20]