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
Fret revived the idea in the late seventies on his innovative instrument, the Starrboard. Rickenbacker employed a slanted fret, but it was not multi scale, or fanned. Novax Guitars among others offers such guitars today. The appearance of angled frets on these modern instruments belies the antiquity of this technique. Scalloped fretboard: Scalloping involves removing some of the wood between some or all of the fret. This is intended to allow a lighter touch for more precise fingering, while easing bends or vibratos (since there's no contact between the fingertips and the wooden surface of the fingerboard). It has some popularity