Jeff Olson is an American musician and the original drummer for the doom metal band Trouble. He is also the founding member of Retro Grave, keyboardist for Victor Griffin's In~Graved, proprietor of Upland Recording, and former drummer for The Skull.

Douglas Theodore Pinnick, sometimes stylized as dUg Pinnick or simply dUg, is an American musician best known as the bass guitarist, co-lead vocalist, and songwriter for the hard rock and progressive metal band King's X. He has performed on 15 albums with King's X and recorded four solo albums. Pinnick has also participated in numerous side projects and has multiple guest appearances to his credit. He is recognized for his unique vocals, and heavily distorted bass tone. Pinnick often plays bass with a guitar pick, though he has also been seen using his fingers.