"Hammerschlag has a complete command of his instrument and yet his choice is often to make the simplest and most profound note choice possible. His warm, buttery tone combined with his thorough knowledge of western harmonic languages make his improvisations a lesson in a kind of empathic logic-structure-building. He is unique and has a sense of humor that comes out forcefully through his music. His depth of focus, cultivated through years of meditation and practice gives his phrasing a kind of irresistible magnetism."

     - Aaron Alexander

Arnold has led bands featuring Michael Bisio, Chris Corsano, Sam Bardfeld, Will Holshouser, Brian Glassman, Fima Ephron, Aaron Alexander, Ethan Iverson, Michel Gentile, Owen Howard and Phil Haynes. He studied with Jim Knapp, Jerry Granelli, Julian Priester and Jay Clayton.