This is the "Deep D Open Major" tuning for a Guitar, an intriguing variant of the classic Open D tuning. As described, it shares similarities with an Open D# variant, but is transposed down to the key of D, offering a rich and resonant sound profile.

Verbal Analysis

At its core, this tuning provides a powerful D Major chord when strummed open. The unique feature is the doubling of the low D, with both the 6th and 5th strings tuned to D2, creating an incredibly deep and resonant foundation. This gives the tuning a particularly full and symphonic quality, making it ideal for drone-based music, blues, slide guitar, or any style where a strong, open major chord is desired. The overall lower tension from tuning all strings down contributes to a slacker feel, which can be advantageous for bending and vibrato, but might require a heavier string gauge for optimal playability and intonation.

Technical Analysis

The open notes are specifically D2-D2-A2-D3-F#4-A3. This configuration clearly outlines a D Major chord (D-F#-A) across all strings, with octaves and fifths reinforcing the tonality:

• String 6: D2 (Root)
• String 5: D2 (Root, Octave Unison with String 6)
• String 4: A2 (Perfect 5th)
• String 3: D3 (Root, Octave above D2)
• String 2: F#4 (Major 3rd)
• String 1: A3 (Perfect 5th, Octave above A2)

This arrangement allows for immediate D Major chords simply by strumming the open strings or barring any fret for subsequent major chords (e.g., first fret for D# Major, second fret for E Major, etc.). The prominent Major 3rd (F#) on the second string and the strong fifths (A) on the fourth and first strings create a bright, full sound. The double low D is a distinctive element, setting it apart from standard Open D (DADF#AD) by offering an even deeper, more resonant bass.

Chordal Possibilities

Beyond the immediate major chords, the predictable intervallic structure makes finding other voicings intuitive:

• Major Chords: As noted, barres across any fret yield a major chord.
• Minor Chords: To achieve a D minor, you would need to flatten the F# on the 2nd string to F. This is easily done by fretting the 2nd string at the 1st fret (if open is F#) or adjusting the tuning temporarily.
• Suspended Chords: By altering the 2nd (F#) or 1st (A) string, various suspended chords (Dsus2, Dsus4) can be formed with relative ease. For example, playing the 2nd string open (F#) but pressing it down one fret (E) might yield a Dsus4 if the context allows.
• Drone Power: The repeated D notes and open A's make this an excellent tuning for creating sustained drones and modal explorations, particularly in D Mixolydian or D Dorian scales.

How to Tune to Deep D Open Major

This tuning requires significant adjustments to most strings, all of them being tuned down. Please proceed carefully and use a reliable tuner. For strings with significant drops (exceeding -4 semitones), consider using a heavier gauge string to maintain optimal tension and intonation.

• String 6 (Low E to D2): Tune down 2 semitones.
• String 5 (A to D2): Tune down 7 semitones. Caution: This is a significant drop; a different string gauge is advised for long-term use.
• String 4 (D to A2): Tune down 5 semitones.
• String 3 (G to D3): Tune down 5 semitones.
• String 2 (B to F#4): Tune down 5 semitones.
• String 1 (High E to A3): Tune down 7 semitones. Caution: This is a significant drop; a different string gauge is advised for long-term use.