Capo plays a B note for any capo position at or below the seventh fret), and thus a performer does not need to adjust for or relearn the entire fretboard as they might with retuning. The scale length of the strings of an instrument affects the timbre of the strings, and thus the use of a capo may alter the tone of the instrument. Musicians also use capos to bring a guitar tuned below standard up to standard tuning. Manufacturers sometimes recommend tuning a twelve-string guitar a whole-step or more below standard to offset the additional stress of the additional strings.
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