Octave twelve Octave twelve An octave twelve is a type of 12-string guitar fitted with a short-scale neck and a small solid body. It is tuned one octave higher than a standard guitar giving it the tonal range of a mandolin and enabling a guitarist to achieve a mandolin sound without learning mandolin fingering. The effect is similar to that of capoing a standard 12-string guitar at its twelfth fret. However, unlike a standard 12-string guitar, the courses of strings tuned in unison, rather than in octaves. The octave twelve was invented by engineers at Vox, which sold the octave twelve as
Scale length (string instruments) All other things being equal, increasing the scale length of an instrument requires an increase in string tension for a given pitch. A musical string may be divided by the twelfth root of two formula_1, approximately 1.059463094 and the result taken as the string-length position at which the next semitone pitch (fret position) should be placed from the previous fret (or, in case this is the first calculation, the nut or zero fret) of the instrument. This quotient is then divided again by itself to locate the next semitone higher, and so on. Alternatively, the string may be divided by