How many tunings
General mountain dulcimer or music discussions
Marg, the short answer is that there are 12 possible keys to tune to for any specific tuning.
The important information in your question is the numbers to which you refer. Those refer to scale positions of the notes.
Let's start with D and count the letters until we come back to D.
D = 1
E = 2
F# = 3
G = 4
A = 5
B= 6
C = 7
D = 8
So DAA is 1-5-5, DAC is 1-5-7, DAG is 1-5-4, and DAd is 1-5-8. Those are the 4 main tunings we use. (Although I find the use of modal names for tunings to be confusing, in case you are wondering, 1-5-5 is Ionian, 1-5-8 is mixolydian, 1-5-4 is Dorian, and 1-5-7 is Aeolian.)
You can start on any note, not just D. As you know, EBe and CGc are other 1-5-8 tunings. But you could start on any note you want and arrange the strings in the same pattern. Let's try F.
F = 1
G= 2
A = 3
Bb = 4
C = 5
D = 6
Eb = 7
F = 8
So a 1-5-8 tuning would be FCf. A 1-5-5 tuning would be FCC. A 1-5-4 tuning would be FCBb. A 1-5-7 tuning would be FCEb.
There are twelve notes in the chromatic scale, and we could start this pattern on any of them, so each tuning can be used for any of the 12 keys.
However, in practice, folk, old-timey, bluegrass, or Celtic sessions usually stick to 4 main keys: C, D, G, and A. So you might want to just ensure you know how to play in each of those keys rather than worry about the oddballs like Eb or F or Ab or whatever.
And remember that if you are tuned to the key of D, you can probably tune down to C or up to E, but any more than that you will probably need to change strings.
To your question about GGD, a "normal" 1-1-5 or Ionian tuning in G would be GDD. So your GGD just uses two G drones instead. But to figure out how to use that tuning in other keys, just count.
G = 1
A = 2
B= 3
C#= 4
D = 5
And we don't even have to go any higher. Tune your bass and middle strings to whatever note you want, start on that letter as number 1 and count to 5. That 5 will be the note you want for the melody string.
C, D, E, F, G, so in C, it would be CCG. ABC#DE, so in A it would be AAE.
Again, if you know the alphabet and can count to 8, you can do this yourself.
updated by @dusty: 03/23/21 11:57:23PM