Standard tuning strings. This is done to simplify fingering. A few guitarists, mostly those using tapping, play without this interval, instead tuning in all fourths; thus on a six-string guitar the top two strings become C and F instead of B and E. Other unusual tunings include all major thirds, all minor thirds, and various other choices. In standard notation, the guitar sounds one octave lower than it is written. This is to avoid switching between treble and bass clef, or using ledger lines or 8vb, since it is very common to play past the 12th fret on the E string (E)
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