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
Multi-neck guitar 6-string neck on the bottom and an "octave guitar" for the top neck. This was a 6-string neck tuned an octave higher than the standard guitar, that both extended the range of the instrument, and allowed Maphis to play mandolin-like sounds. Between 1958-1968, Gibson made an instrument of this type which it called the "Double Mandolin" (Gibson EMS 1235). Hybrids with a 6-string guitar neck and a true 8-string mandolin neck were also made (e.g., the 1971 Dawson Electric guitar/mandolin). And Led Zeppelin's John Paul Jones has a triple-neck electroacoustic instrument, custom made for him by luthier Andy Manson, which