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
Zero fret fret 1 to 3 mainly) the elevated fret keeps the string action higher and helps to avoid string buzz. The term "guitar intonation" denotes to what precision the ideal equally tempered musical scale can be produced by a guitar, while "piano intonation" refers to the setup procedure of the individual hammers in the piano keyboard. A conventional nut or an elevated zero fret will cause pitch errors on the lower frets due to the increased pressure on the strings. The fret distances would have to be corrected for that increased tension effect, but with guitars that is not common. On