sympathetic string

Sympathetic strings are an element in some musical instruments that vibrate in response to the sound of other strings being played. This phenomenon is not unique to Western music but is a fundamental feature in many Eurasian chordophones.

Instruments like the Hindustani sarod and sitar, the South Asian sarangi, the Norwegian Hardanger fiddle, and the viola d'amore all utilize sympathetic strings. These strings, typically made of thin brass or steel, are tuned to the notes of the mode being played. When other strings are sounded, these sympathetic strings vibrate, reinforcing upper harmonics and contributing to a bright, silvery tone. This effect is also present in instruments like the piano, zither, and harp, though it may not be their central characteristic.1