The Open GBDABD tuning is a rich and vibrant variation, offering a full, resonant sound that's particularly suited for blues, folk, rock, and ambient music. When strummed open, the strings ring out a G Major 9th chord, creating a lush, expansive soundscape. This tuning simplifies many chord shapes and encourages creative melodic and rhythmic playing over a strong harmonic foundation.

Technical Analysis:

• Overall Chord Structure: The open strings G-B-D-A-B-D form a G Major 9th chord (G-B-D-A), with the B and D notes repeated across octaves for enhanced resonance and fullness.
• Root and Fifth: The tuning maintains strong G (root) and D (fifth) notes on both the lower and higher strings, providing a solid, drone-like foundation.
• Major Third and Ninth: The presence of B (major third) and A (major ninth) notes contributes to the bright, open quality of the tuning, adding harmonic color and complexity.
• Intervals (from low G):
  • String 6 (G2) - Root
  • String 5 (B2) - Major 3rd
  • String 4 (D3) - Perfect 5th
  • String 3 (A3) - Major 9th (compound major 2nd)
  • String 2 (B3) - Major 10th (compound major 3rd)
  • String 1 (D4) - Perfect 12th (compound perfect 5th)

Accessible Chords & Playing Styles:

• Open G Major 9th: The tuning's natural resonance makes an open G Major 9th chord effortlessly beautiful, perfect for rich strumming patterns.
• Drone and Riffing: The repeated G and D notes across octaves provide excellent opportunities for drone playing, pedal points, and powerful open-string riffs.
• Slide Guitar: This open tuning is highly conducive to slide guitar, allowing for smooth glissandos and soulful melodies over the G major harmony.
• Root-Fifth Power Chords: Moving one or two fingers across the fretboard, especially on the lower strings, will easily yield powerful root-fifth power chords, useful in rock and blues.
• Relative Major/Minor: With a G major foundation, exploring relative minor chords like E minor or modes around G will be intuitive. Barre chords up and down the neck will easily create other major and minor harmonies.

Here are the specific notes for each string in the Open GBDABD tuning, from the lowest (6th) to the highest (1st) string:

• 6th String: G2 (Low G)
• 5th String: B2 (Low B)
• 4th String: D3 (Middle D)
• 3rd String: A3 (Middle A)
• 2nd String: B3 (High B)
• 1st String: D4 (High D)

How to Tune Your Guitar:

To achieve the Open GBDABD tuning, you will adjust your standard E-A-D-G-B-E tuning as follows. Pay close attention to the direction and number of semitones for each string.

• 6th String (Low E to G2): Tune up 3 semitones. This brings your standard low E string up to a G2.
• 5th String (A to B2): Tune up 2 semitones. This brings your standard A string up to a B2. Mathematical calculation confirms this is correct (A -> A# -> B is 2 semitones).
• 4th String (D to D3): Keep as is; no change (0 semitones). Your standard D string remains D3.
• 3rd String (G to A3): Tune up 2 semitones. This brings your standard G string up to an A3. Mathematical calculation confirms this is correct (G -> G# -> A is 2 semitones).
• 2nd String (B to B3): Keep as is; no change (0 semitones). Your standard B string remains B3.
• 1st String (High E to D4): Tune down 2 semitones. This brings your standard high E string down to a D4. Mathematical calculation confirms this is correct (E -> Eb -> D is -2 semitones).

Important Note on String Gauge: All string movements for this tuning are within the recommended range of -4 to +4 semitones. Therefore, a change in string gauge is generally not advised for this specific tuning, making it safely playable with standard string sets.