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
Basic physics of the violin pitch, which may be described in terms of frequency. The playing tension of a violin string ranges from about to . The length of the string also influences its pitch, and is the basis for how a violin is played. Violinists "stop" a string with a left-hand fingertip, shortening its playing length. Most often the string is stopped against the violin's fingerboard, but in some cases fingertip contact alone is enough to stop the string at the desired sounding length. Stopping the string at a shorter length has the effect of raising its pitch. String material affects the quality of