His background is mostly in the jazz world ( he was a professor of jazz studies at Berklee ) .
His background played bluegrass as a child ( his first instrument was the upright bass , which he picked up at the age of seven . )
His background is mostly in the jazz world ( he was a professor of jazz studies at Berklee ) but played bluegrass as a child ( his first instrument was the upright bass , which he picked up at the age of seven . )