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
Scale length (string instruments) construction using the Novax Fanned-Fret system that "fan outward" for the ability to play in tune with the unequal scale lengths of each string that is used to find the optimal equal tonal response and equal string tension from string-to-string for easier playing is represented by Dingwall Basses, who uses a 37" to 34" span on their Prima, Z1, Z2, and Afterburner original designs and a shorter 34.25" to 32" span for their "Super J" Jazz Bass design. Helios R-Evolution 7 strings bass Heliosguitars Helios ANTARES 6 strings bass Heliosguitars The scale length of a piano is the length of