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
Reentrant tuning and old-time music. The four string plectrum banjo (more often used in jazz) and the four string tenor banjo lack this shorter string, and are rarely tuned in re-entrant fashion. Reentrant tuning On a stringed instrument, a break in an otherwise ascending (or descending) order of string pitches is known as a re-entry. A re-entrant tuning, therefore, is a tuning where the strings (or more properly the courses) are not all ordered from the lowest pitch to the highest pitch (or vice versa). Most common re-entrant tunings have only one re-entry. In the case of the soprano ukulele, for example,