Violin where a stopped note sounds a unison or octave with another (open) string, causing it to resonate sympathetically. Students often use these ringing tones to check the intonation of the stopped note by seeing if it is harmonious with the open string. For example, when playing the stopped pitch "A" on the G string, the violinist could play the open D string at the same time, to check the intonation of the stopped "A". If the "A" is in tune, the "A" and the open D string should produce a harmonious perfect fourth. Violins are tuned in perfect fifths, like
String (music) invention of wound strings, such as nylon covered in wound metal, was a crucial step in string instrument technology, because a metal-wound string can produce a lower pitch than a catgut string of similar thickness. This enabled stringed instruments to be made with less thick bass strings. On string instruments that the player plucks or bows directly (e.g., double bass), this enabled instrument makers to use thinner strings for the lowest-pitched strings, which made the lower-pitch strings easier to play. On stringed instruments in which the player presses a keyboard, causing a mechanism to strike the strings, such as a