D'Addario H610-34M double bass string set 3/4, medium, nickel Helicore Orchestral bass strings are multi-stranded steel core strings that produce a warm tone quality with excellent bow response. The core design makes for strings that are very easy to play under the left hand. Damping is optimized for arco use, making them ideal for symphonic performance. Helicore Orchestral also work well for pizzicato applications where a very warm, less-sustaining sound is desired.