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
Twelve-string guitar downward strum is the higher-octave string; however, Rickenbacker usually reverses this arrangement on its electric 12-string guitars. The tuning of the second string in the third course (G) varies: some players use a unison string, while others prefer the distinctive high-pitched, bell-like quality an octave string makes in this position. Another common variant is to tune the octave string in the sixth (lowest) course "two" octaves above the lower string, rather than one. Some players, either in search of distinctive tone or for ease of playing, remove some doubled strings. For example, removing the higher octave from the three bass