operates String Theory Luthiery in Sioux Falls, S.D. On the left, his highly idiosyncratic 5-string mandolin, complete with Novax fretboard and Kent Armstrong pickup. It's fully hollow and the top is made of cocobolo. Scale length goes from 16 inches on the C string to 14 inches on the E. On the right, a semi-hollow baritone 5-string with a pair of pickups and a maple top.