A Crash Course in Open and Alternate Tunings
For many generations, great guitarists have understood the power of alternate tunings and open tunings — alternate tunings being deviations from standard tuning's tried-and-true EADGBE, low string to high string; open tunings being any tuning which forms a full chord when all open strings are strummed together.
To the uninitiated, however, these departures from standard tuning can be anywhere from slightly confusing to utterly baffling. It's easy to get into a mindset that says that standard is "normal" and anything else is "not quite right," and certainly it might seem that way to your fingers and ears when you first venture into uncharted musical waters. The truth is, however, using an alternate tuning will actually make it a lot easier to play many styles of music, and chances are you'll feel at home with the changes a lot quicker than you might expect after just a short time of dedicated practice.
Many famous artists have used alternate tunings, from The Beatles and Rolling Stones to Led Zeppelin and many, many more.
Influential folk guitarist Davy Graham, who dies this week, was the person who first introduced the DADGAD tuning.
Check out these basic chords for some popular open and alternate tunings. Notice how they put melodic runs within easy reach, for certain types of fingerstyle playing in particular, by putting open strings within the key or scale of the song in question, and also how they make slide (bottleneck) playing much easier by creating chords that can be played on all open strings together or on any barred fret.
Open Tunings (clik to enlarge):
from left: Open D, Drop D, Double Drop D, DADGAD, Open G
Traditionally, one of the things that has discouraged many players from exploring alternate tunings thoroughly is the sheer work of changing the guitar from one tuning to another and back again. Professional performers who regularly use more than one tuning generally keep a number of different guitars on stage in different tunings, at arm's reach and ready to go, just to ease the work of all that tuner twisting.
[originally from Gibson.com - read full article here]