Bass guitar the 3rd, 5th, 7th, 9th fret and 12th fret (the 12th fret being the octave of the open string) and on the octave-up equivalents of the 3rd fret and as many additional positions as an instrument has frets for. Typically, one marker is on the 3rd, 5th, 7th and 9th fret positions and two markers on the 12th fret. The long scale necks on Leo Fender's basses—with a scale length (distance between nut and bridge) of — set the standard for electric basses, although "short scale" instruments, such as the Höfner 500/1 "violin bass" played by Paul McCartney, and the
Fret generally perpendicular to the instrument's neck centerline and parallel to each other, on a "fanned" fretboard, the frets are angled (spread like a fan) with only one center fret perpendicular to the neck’s centerline. This gives the lower-pitched strings more length and the higher strings shorter length (comparable to a piano or a harp where heavier strings have different lengths). The idea is to give more accurate tuning and deeper bass. Some think that fanned frets might be more ergonomic. Fanned frets first appeared on the 16th century Orpharion, a variant of the cittern, tuned like a lute. John Starrett