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
Appalachian dulcimer half," "6½" or "6+" fret a half step below the octave. This enables one to play in the Ionian mode when tuned to D3-A3-D4 (the traditional tuning for the Mixolydian mode), where the scale starts on the open (unfretted) string. This arrangement is often found to be more conducive to chord-melody play. It also became common to add a fret one octave up from the 6+ fret, called the "13+" fret, and by the late 1970s these additional frets had become standard. Eventually, some builders began to offer further additional frets at the "1+" and "8+" positions or (as an