Dsus4: D A D G A D (aka Dad Gad)
This tuning has a colorful history and is popular among Celtic players. It’s sometimes referred to by it’s notes in a name “Dad Gad”. All the intervals (the distance between two notes) in Dsus4 are perfect 4ths except one very small interval of one whole step between the G and the A.
Having a major second interval like this can open up some possibilities. For example you can now play consecutive scale notes without having to fret either note (or fretting the same fret). This is something that you can’t do in a lot of other tunings, so as you can see there are a lot of possibilities.
Getting the Guitar into Dsus4
The following chart shows D A d g a d in comparison to standard tuning.
|Strings||Standard||D A d g a d||Changes||Fret to Match
Adjacent Open String
|6||E||D||Lower 1 whole-step||7|
|1||E||D||Lower 1 whole-step||-|