DAA or DAD as primary tuning ?
General mountain dulcimer or music discussions
Changing to these different tunings is pretty easy. Starting with your present tuning of DAA:
1- to tune to DAdd, tighten the melody string(s) to the same note as the 7th fret on the bass string.
2- to tune to the other tunings, loosen the melody strings from DAdd to the note desired.
3- to tune to other tunings, such as CGc, etc, you usually loosen the strings [there are a few exceptions]. Keep in mind that the DAdd tuning tightens the strings to very close to their maximum strength, about 2-3 notes below breaking point.
For reference; a standard MD, bass D is D3, A is A3, melody D is D4, and it is written as DAd(d). Bass dulcimers are tuned an octave lower, D2, A2, D3.