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
Tenor guitar six string guitar. As string tension for any pitch increases with length, some have said these guitars cannot be tuned to the normal CGDA fifths tuning because the A string cannot be tuned to pitch without breaking. However, there are a variety of available methods for addressing this point and bringing the longer-scaled tenor guitar up to standard tuning and pitch: special string sets; strings extracted from a seven string guitar set; etc. Tenor guitars can also be tuned to a reentrant CGDA tuning where the A and sometimes the D are pitched an octave lower. The plectrum guitar is