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
Tenor guitar six string guitar. As string tension for any pitch increases with length, some have said these guitars cannot be tuned to the normal CGDA fifths tuning because the A string cannot be tuned to pitch without breaking. However, there are a variety of available methods for addressing this point and bringing the longer-scaled tenor guitar up to standard tuning and pitch: special string sets; strings extracted from a seven string guitar set; etc. Tenor guitars can also be tuned to a reentrant CGDA tuning where the A and sometimes the D are pitched an octave lower. The plectrum guitar is