A 12-string guitar produces that big, shimmering, chorus-like sound because of how its strings are paired, and understanding that pairing is the key to tuning one properly. It looks daunting at first with double the strings and double the tuning pegs, but the logic behind it is straightforward.

How the string pairs work

A 12-string is tuned in the same E-A-D-G-B-E pattern as a standard 6-string, but each of those six notes is played by a pair of strings, known as a course, rather than a single string. The lowest four courses (E, A, D and G) each pair a standard string with a second string tuned a full octave higher, which is what creates that shimmering, chiming quality. The top two courses (B and high E) are unison pairs, tuned to the same pitch rather than an octave apart, since strings light enough to reliably tune an octave above the high E and B don't hold up well in practice.

Tuning order

Work through the courses from low to high, tuning both strings in each pair before moving to the next: low E pair, A pair, D pair, G pair, B pair, then high E pair. Whether you're using an electronic tuner or the fifth-fret method, remember the same exception that applies on a 6-string: the B course is tuned from the G course at the 4th fret, not the 5th.

A few things that catch people out

• It's easy to accidentally tune the octave string in a bass course to the wrong octave. If it sounds off compared to its partner string, check you haven't tuned it a full octave too high or low rather than just slightly out.
• Twelve strings under tension put considerably more load on the neck than six, so 12-string guitars are generally built with this in mind. Even so, be gentle when bringing a 12-string up from well below pitch, and avoid over-tightening any single string.
• New strings on a 12-string take a little longer to stretch in and settle than a standard set, simply because there are twice as many to stabilise.

Why it's worth the extra care

The distinctive 12-string sound, heard across so much classic folk, country and rock recording, only really works when both strings in each course are accurately in tune with each other. A slightly out-of-tune pair doesn't sound like a stylistic chorus effect, it just sounds out of tune. Take your time with each course and check it against the octave or unison partner string before moving on.