A stringed instrument with sympathetic strings is provided that includes (in addition to the primary elements corresponding to standard instrument elements) sympathetic strings, one or more supplementary bridges, a supplementary string termination assembly, and a set of supplementary tuners. The sympathetic strings are stretched diagonally across the soundboard of the instrument, with one end of each string attached at a supplementary tuner and the other end attached at a supplementary string termination assembly. The sympathetic strings are spaced by the supplementary bridge(s) a sufficient distance from the soundboard to prevent interaction with it during vibration of the string during playing. The sympathetic strings are activated by sound vibrations created by the bowed primary strings, may additionally be activated by plucking or strumming, and may be manually muted.