Acoustic bass guitar of acoustic bass guitars. The bajo sexto, with six pairs of strings, resembles a twelve-string guitar tuned an octave lower. The heavy gauge strings generate a large string tension, yet the guitar is built relatively lightly. Musicians began to use the bajo sexto in Texas in the 1920s with the rise of "Tex-Mex" music, and remains in common use to play parts that would be played by the piano in traditional American popular music. It matches the standard tuning of a 12-string guitar, one octave lower. The tuning of these instruments is (capital letters are an octave lower than small
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