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, the re-entry is between the third and fourth strings, while in the case of the Venezuelan cuatro it is between the first and second strings.

Instruments usually tuned in this way include:

Instruments often (but not always) re-entrantly tuned include:

Instruments not usually considered re-entrant, but which have common re-entrant alternate tunings:

The standard tunings for instruments with multi-string courses, such as the twelve string guitar, eight string bass, or Colombian tiple are not considered re-entrant, as the principal strings of each course are ordered from lowest to highest.

Ukuleles other than the tenor and baritone are most commonly tuned in re-entrant fashion. These conventional re-entrant tunings are sometimes known as high 4th tunings.

Non re-entrant tunings, also known as low 4th tunings, exist for these instruments.

The Andean charango, a small 5-course, 10-string guitar frequently made from an armadillo shell, is most usually tuned in re-entrant fashion, with re-entry between the third and second courses.

Other members of the charango family, such as the hualaycho and charangon are usually similarly tuned; the ronroco is often, but not always tuned re-entrantly.

The ten string classical guitar was originally designed for a specific re-entrant tuning invented by Narciso Yepes, now called the Modern tuning. Both this and other re-entrant tunings, such as the Marlow tunings, are now used, as well as non re-entrant tunings such as the Baroque. These tunings may also be used on related instruments, such as ten string electric and jazz guitars.

The Venezuelan cuatro is a member of the guitar family, smaller in size and with four nylon strings. The cuatro is similar in size and construction to the ukulele and it is one of several South American instruments by the name of cuatro, which is Spanish for four. Despite of the name, not all instruments called Cuatro have four strings, but the Venezuelan Cuatro, preserves this number of strings.

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Wikipedia