The 12 string guitar came into its own during the folk music boom of the 1960′s. In its acoustic and electric forms, it was played to great effect by guitarists in many genres, such as George Harrison of The Beatles, and Roger McGuinn of The Byrds.
The 12 string guitar is usually tuned to the same notes as the six string, that is E A D G B E. Instead of six single strings, it has six pairs – or “courses” of two strings. The key to the unique sound of the 12 stringed instrument is the difference in frequency between the two strings in each course.
There is no special 12 string guitar tuning, but the instrument can be played in standard tuning or in alternate tunings. Many guitar players enjoy playing the 12 string in Drop D tuning. Because the extra strings cause the neck to warp over a period of years, 12 string guitars are sometimes tuned lower than concert pitch to minimize the tension on the neck.
Each course of strings can be tuned to exactly the same frequency. Many guitarists tune only the second and first strings – the notes B and E – in unison; the rest are tuned one octave apart. The exception to this rule is the G string which to many players sounds more pleasing when the two G strings are tuned an octave apart, but others prefer them tuned to sound in unison.
For the purposes of this tutorial, the pairs of strings in the sixth, fifth, fourth and third courses will be tuned one octave apart, and the B and E courses will be tuned in unison.
If you examine a 12 string guitar, you will see that the pairs of strings in each of the E A D G courses are of different gauges. The thicker string is in the lower position, and is tuned first. The strings in the B and E courses are the same gauge. The procedure for tuning a 12 string guitar is to sit with the guitar in playing position, and tune the lower string of each course as you would for a six string guitar.
The next step is to tune the top strings of the second and first courses to match the lower strings. Once you have those strings in tune, it is time to tune the top strings in the sixth, fifth, fourth and third courses an octave higher than the lower strings.
To get the pairs of strings sounding an octave apart, tune the top G string to the third fret of the first string. The top D string is tuned to the note at the third fret of the second string. The top A string is tuned to the second fret on the third string. The top E string matches the E on the second fret of the fourth string.
This looks complicated on the page, but in practice it is easily understood.