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
Acoustic bass guitar are quite rare. Like the traditional electric bass and the double bass, the acoustic bass guitar commonly has four strings, which are normally tuned E-A-D-G, an octave below the lowest four strings of the 6-string guitar. Like the electric bass guitar, models with five or more strings have been produced, although these are less common. In part, this is because the body of an acoustic bass guitar is too small to produce a resonance of acceptable volume at lower pitches on the low "B" string. One solution uses the five string acoustic bass to add an additional high string ("E-A-D-G-C")