D minor 9th - 9 String: An Expansive D Minor Landscape

This unique 9-string guitar tuning, named "D minor 9th - 9 string", creates an incredibly rich and deep harmonic foundation rooted in D minor. Building upon a core D minor 9th chord (D-F-A-C-E), this tuning spreads these notes across an expansive range, offering a palette of dark, resonant tones perfect for atmospheric music, extended jazz voicings, or heavy, low-end riffing. Its construction is particularly interesting, featuring a blend of consonant perfect intervals and compelling dissonances.

Technical Analysis:

• Root and Chord Tones: The open strings are tuned to D1, F1, A1, D2, A2, E3, F3, C4, E4. This directly spells out a D minor 9th chord (D-F-A-C-E) across the strings, with multiple octaves of D and A, and duplicates of F and E. Specifically, we have D (root), F (minor 3rd), A (perfect 5th), C (minor 7th), and E (major 9th).
• Intervalic Structure: Examining the intervals between adjacent strings reveals a fascinating layout:
  • String 9 (D1) to String 8 (F1): Minor 3rd (3 semitones)
  • String 8 (F1) to String 7 (A1): Major 3rd (4 semitones)
  • String 7 (A1) to String 6 (D2): Perfect 4th (5 semitones)
  • String 6 (D2) to String 5 (A2): Perfect 5th (7 semitones)
  • String 5 (A2) to String 4 (E3): Perfect 4th (5 semitones)
  • String 4 (E3) to String 3 (F3): Minor 2nd (1 semitone) - A notable cluster!
  • String 3 (F3) to String 2 (C4): Perfect 5th (7 semitones)
  • String 2 (C4) to String 1 (E4): Major 3rd (4 semitones)
• Harmonic Implications: The presence of the minor 2nd interval between E3 and F3 on adjacent strings (Strings 4 and 3) creates a powerful dissonance that can be used for tension, leading tones, or unique sustained voicings. The wide perfect 5ths and 4ths provide a stable backdrop for this complexity.

Open Chords and Playing Potential:

With this tuning, the guitar itself becomes a giant D minor 9th chord when strummed open. This provides an immediate, full, and rich harmonic texture without any fretting. Beyond the open chord, the unique string intervals open up various possibilities:

• Instant D minor 9th: A full, nine-note D minor 9th chord is available just by strumming all open strings.
• Power Chords: The perfect 4ths (A1-D2, A2-E3) and perfect 5ths (D2-A2, F3-C4) make easy access to power chords and sustained drones across multiple string groups. For instance, D2-A2 on strings 6 and 5, or A2-E3 on strings 5 and 4.
• Minor Triads: The lowest three strings (D1-F1-A1) form a clear D minor triad, offering a deep, fundamental bass. Similarly, F1-A1-D2 (strings 8, 7, 6) can be voiced as an F major triad in first inversion.
• Upper Register Voicings: The top three strings (F3-C4-E4) create a C major triad with an added F, or an F major 7th (#11) chord, offering bright, jazzy extensions in the higher register.
• Dissonant Textures: The E3-F3 interval is ripe for creating sustained, ringing dissonances or for exploring modes that highlight this semitone, such as Phrygian or Locrian.

This tuning encourages exploration beyond standard chord shapes, pushing players to discover new voicings and melodic patterns that leverage its unique architecture. It is particularly well-suited for progressive metal, ambient soundscapes, or experimental jazz where deep, complex harmony and extended range are desired.

How to Tune to D minor 9th - 9 String:

Please note that all string movements described below are relative to a standard starting point for each string. Tune carefully and always check your string's tension, especially when tuning up.

• String 9 (Lowest D1): Tune up 1 semitone. This is a minor adjustment.
• String 8 (F1): Tune down 1 semitone. A slight decrease in tension.
• String 7 (A1): Tune down 2 semitones. A moderate decrease in tension.
• String 6 (D2): Tune down 2 semitones. A moderate decrease in tension.
• String 5 (A2): Keep as is; no change (0 semitones). This string acts as a stable reference.
• String 4 (E3): Tune up 2 semitones. A moderate increase in tension, proceed with care.
• String 3 (F3): Tune down 2 semitones. A moderate decrease in tension.
• String 2 (C4): Tune up 1 semitone. A minor adjustment.
• String 1 (Highest E4): Keep as is; no change (0 semitones). This string acts as a stable reference.

Important Safety Note: All movements in this tuning are within a safe range of +/- 2 semitones. However, always exercise caution when adjusting string tension. If you plan to frequently switch between tunings with larger semitone movements (exceeding negative 4 or positive 4 semitones), consider using different gauge strings for optimal performance and to prevent string breakage or damage to your instrument.