Octave mandolin in unison. Alternate tunings exist in which the strings in some courses are tuned to octaves, rather than unisons, but this is more typical of the Irish Bouzouki. Usually, courses of 2 adjacent strings are doubled (tuned to the same pitch). The standard octave mandolin tuning is G2 G2 • D3 D3 • A3 A3 • E4 E4, so the lowest open strings are tuned to the lowest 'G' on the guitar, and the highest strings are tuned to the same 'E' as the highest string of the guitar. This tuning is one octave below the mandolin (or a fourth
Violin comparable to that of fine full size violins. 5 String violin sizes may differ from the normal 4 string. The instrument which corresponds to the violin in the violin octet is the mezzo violin, tuned the same as a violin but with a slightly longer body. The strings of the mezzo violin are the same length as those of the standard violin. Violins are tuned by turning the pegs in the pegbox under the scroll, or by adjusting the "fine tuner" screws at the tailpiece. All violins have pegs; fine tuners (also called "fine adjusters") are optional. Most fine tuners