The "Double Unison D" tuning is a powerful and resonant open D variant for the guitar, specifically designed to create a massive, droning sound centered around the D note. As its name suggests, a unique characteristic of this tuning is the presence of two pairs of strings tuned in unison: the lowest two strings (6th and 5th) are both tuned to D2, and the middle two strings (4th and 3rd) are both tuned to D3. This creates an incredibly thick and sustained D presence across multiple octaves.

Technical Analysis

The open string notes for this tuning are D2-D2-D3-D3-A3-D4 (from thickest to thinnest string). Let's break down the intervals relative to the root note D:

• 6th String (D2): Root D
• 5th String (D2): Root D (unison with 6th string, creating a thick bass)
• 4th String (D3): Root D (octave above D2)
• 3rd String (D3): Root D (unison with 4th string, creating a thick mid-range)
• 2nd String (A3): Perfect Fifth of D
• 1st String (D4): Root D (octave above D3)

When strummed open, this tuning produces a rich and full Dsus2 chord, overflowing with D and A notes across several octaves. The powerful unisons on the lower and mid-range strings provide immense sustain and a unique textural quality. While it lacks the major third (F#) to be a pure D major, its strong root and fifth create a very stable and versatile foundation. This tuning is excellent for slide guitar, drone music, or any style where a resonant, open sound is desired. Barring across any fret will generally yield a major or sus2 chord based on that fret, making it very accessible for creating full chords with a single finger, expanding its playability beyond just open chords.

How to Tune

To achieve the Double Unison D tuning, you will need to adjust several strings significantly from standard EADGBe tuning. Please note the warnings for strings requiring substantial changes, as these may benefit from a different string gauge for optimal tension and tone. The movements are as follows:

• 6th String (Low E to D2): Tune down 2 semitones from E to D2.
• 5th String (A to D2): Tune down 7 semitones from A to D2. Caution: This is a significant drop. Consider a heavier gauge string to maintain adequate tension.
• 4th String (D to D3): Keep as is; no change (0 semitones).
• 3rd String (G to D3): Tune down 5 semitones from G to D3. Caution: This is a significant drop. Consider a heavier gauge string to maintain adequate tension.
• 2nd String (B to A3): Tune down 2 semitones from B to A3.
• 1st String (High E to D4): Tune down 2 semitones from E to D4.

6th String: D2
5th String: D2
4th String: D3
3rd String: D3
2nd String: A3
1st String: D4