The "Open D Minor 9" tuning is a captivating choice for guitarists seeking a lush, sophisticated sound. It effortlessly conjures dreamy jazzy atmospheres, making it perfect for expressive soloing and intricate chord voicings. Its minor foundation also lends itself beautifully to minor blues contexts, offering a soulful and resonant canvas for improvisation.

As an open tuning, it is exceptionally versatile for slide playing, allowing for smooth glides and expressive bends across the fretboard. Furthermore, the inherent structure of the tuning often simplifies complex voicings, making easy fingering possible even for advanced chords.

Technical Analysis:

The open strings are tuned to D2-A2-C3-F3-A3-E4 (low to high). This arrangement immediately forms a D minor 9 (Dm9) chord when strummed open. Specifically, the notes represent the root (D), fifth (A), minor seventh (C), minor third (F), octave fifth (A), and major ninth (E) of the D minor scale. This rich harmonic foundation means that simply barring across any fret will instantly yield a minor 9 chord in the corresponding key (e.g., barring at the 3rd fret produces an F minor 9, barring at the 5th fret produces a G minor 9).

The consistent interval relationships across the strings, particularly the repetition of the fifth (A2 and A3), and the minor third and seventh, create a highly resonant and melodically rich sound. The presence of the major ninth (E) adds a characteristic open and ethereal quality to the minor tonality, differentiating it from a simple Dm7.

Chords Accessible:

• Open Strings: D minor 9 (Dm9)
• Bar Chords: Barring any fret will produce a minor 9 chord (e.g., 1st fret for Ebmin9, 5th fret for Gmin9).
• Accessible Shapes: The structure also makes it easier to find other minor and dominant shapes by adjusting a few fingers, especially those incorporating the minor third and seventh. The open nature provides a deep, full sound for these chords.

How to Tune:

When making significant tuning changes, especially those exceeding -4 or +4 semitones, it is generally advisable to consider using a different string gauge to prevent damage to your instrument or ensure optimal tone and playability. Always tune carefully and gradually.

• String 6 (Low E): Tune down 2 semitones from E2 to D2. This is a significant drop, so proceed with care.
• String 5 (A): Keep as is; no change (0 semitones) from A2.
• String 4 (D): Tune down 2 semitones from D3 to C3.
• String 3 (G): Tune down 2 semitones from G3 to F3.
• String 2 (B): Tune down 2 semitones from B3 to A3.
• String 1 (High E): Keep as is; no change (0 semitones) from E4.