In these tables, the treble string is at the top.
Because it is the highest-pitched string, we call it the “top” or 1st string.
But if you play a guitar the normal way, it’s on the bottom as you look down at the strings as you play them.
So it’s not exactly logical.
The key to retuning the guitar frequently while people are waiting is to pick one string to use as an anchor so you don’t get hopelessly lost.
The more strings you’re going to retune at a time, the more important this is.
If you have to actually retune all six strings, pick one string as your first anchor, tune as many strings as you can to it and get them in tune with each other, then pick a second anchor and retune the first anchor.
In general you want to pick as your anchor a string that will be, in the new tuning, in octaves, fourths, or fifths to as many of the strings as possible.
So, for example, if you start in “standard” and want to go to Open G, pick the D string as the anchor and tune the bass and top strings in octaves to it and then the fifth string in fifths.
Finally, check the tuning of the second string, the only third.
The reason for doing it this way is that it’s easier to hear octaves, fourths, and fifths accurately. Thirds are harder to tune precisely, so leave them until last, and don’t saddle yourself with an anchor string that requires a lot of them.
As another example, to go from Open G to Open C, pick the G string as the anchor, and tune the Cs to it (fifths).
Finally tune the top string (the third).
It is actually very quick once you’re in the habit of it.
The same as standard tuning except that the bottom E is dropped to D.
The key of D sounds a lot better like that.
There are certain things you have to work around to play in this tuning, most notably that to form a G chord you either hit the fifth fret on the sixth string and the third on the top string and you avoid hitting the fifth string
|Drop D tuning|
This is of course the easiest tuning to adopt from “standard”.
Just tune the bottom string down and there you go.
One thing that may not be obvious, though: it’s a very nice tuning for playing in, of all things, a minor, because you get such a nice, full sound on the either D major or d minor, both useful chords in a minor.
This is the first genuine “open” tuning, which means simply that if you strum all the strings leaving them open without fretting any of them, you get a full chord, in this case G.
|Open G tuning|
In other words, you tune both the top E and bottom E down to D and the fifth string down to G from A.
If you’re moving to Open G from Drop D, therefore, you only need to retune two strings.
Considerations like this may play a part in the order you play songs
There are actually two different versions of Open C. The one that most people usually mean is:
|Open C tuning|
This is more radical than the others so far.
From “standard” you leave the first string, tune the second string *up* a half tone, leave the third string, tune the fourth and five down a whole tone each, and tune the bass string down two whole tones.
Tunings like this respond well to using extra-heavy 5th and 6th strings.
Like Open G, this tuning’s a little bit limited, in that you’re stuck with that top third all the time. The other version of Open C, which isn’t used much is:
|Open C tuning|
This is even more radical than the first version of Open C, in that you wind up tuning the first three strings down two whole tones, the 4th and 5th down a whole tone each, and the bass string down two whole tones again.
But of course it all depends where you start from.
If you’re in Open G, moving to Open C is retuning 4 strings no more than a whole tone each (although the second Open C is still more work).
Open D is the same as that second Open C tuning, only a whole tone higher, and is much more commonly used than that one.
|Open D tuning|
From standard, four strings are different. Top two down a whole tone, third down a half-tone, fourth and fifth stay the same, bottom string
down a whole tone.
Arguably, a better term for DADGAD would be “D modal”.
Because there are no thirds in it you can play it as either major or minor.
A full explanation of DADGAD and some useful links are available at Wikipedia’s DADGAD page.
DADGAD is used by increasing numbers of players, but was first popularised (many say invented) in the UK by Davy Graham and has it’s leading champion in Pierre Bensusan.