Mandolin are used. Usually, courses of 2 adjacent strings are tuned in unison. By far the most common tuning is the same as violin tuning, in scientific pitch notation G–D–A–E, or in Helmholtz pitch notation: g–d′–a′–e″. Note that the numbers of Hz shown above assume a 440 Hz A, standard in most parts of the western world. Some players use an A up to 10 Hz above or below a 440, mainly outside the United States. Other tunings exist, including "cross-tunings", in which the usually doubled string runs are tuned to different pitches. Additionally, guitarists may sometimes tune a mandolin to
Contrabass guitar Contrabass guitar A contrabass guitar is a low-register plucked string instrument in the guitar family with four, five or six strings. It is often called, simply, a "six string bass guitar". The "five string bass guitar" is rarely called a contrabass guitar, even though it typically has the same lowest note. Contrabass guitars have been around since 1899, when a "Grand Concert Contra Bass Guitar" was listed in Joseph Bohmann's catalogue. Bohmann, a violin, mandolin, guitar and zither manufacturer from Chicago, developed a large 6-string guitar. While some logically speculate that this instrument was tuned one octave lower than a