Slam Stewart

Leroy Eliot "Slam" Stewart was an American jazz double-bass player whose trademark style was his ability to bow the bass and simultaneously hum or sing an octave higher. He was a violinist before switching to bass at the age of 20. From Wikipedia (https://en.wikipedia.org/wiki/Slam_St...) under Creative Commons Attribution CC-BY-SA 3.0 (http://creativecommons.org/licenses/b...)