Seven-string guitar string is augmented with a high octave string. Many of McGuinn's notable guitar solos utilize the G string of the twelve-string guitar to perform the main melody, and therefore the Martin seven-string guitar was designed to achieve this extended range playing without the need for doubling all six of the guitar's strings. In 2010, Inox Guitars has created a mix of the Brazilian Viola caipira and the Russian semistrunka (семиструнка). This instrument has 2 bass strings (as the 6th and 7th strings of the semistrunka) and five treble courses (as the Viola caipira) and it is used in open tuning
Eight-string bass guitar Eight-string bass guitar An eight-string bass guitar is a type of bass guitar with double course strings normally tuned in octaves, with both strings in a course usually played simultaneously. As on a 12-string guitar, this produces a natural chorus effect due to the subtle differences in string timbre. Such approach has been extended with the introduction of 10-, 12-, 15- or more-string bass guitars, which either double the strings of standard 5- or 6-string basses or even triple the strings of normal 4-, 5- or 6-string basses. The 8-string bass guitar was invented by electrical engineer, bass player and