He had a powerful voice and stamina adequate for the most demanding parts .
He was not a thunderer , and never performed as Wagner 's vocally athletic , bellowing bassos Hagen , Hans Sachs , nor Wotan .
Although he had a powerful voice and stamina adequate for the most demanding parts , he was not a thunderer , and never performed as Wagner 's vocally athletic , bellowing bassos Hagen , Hans Sachs , nor Wotan .