Open D9: A Rich, Extended Sonic Canvas

This intriguing Open D9 tuning transforms your guitar into a complex harmonic instrument, moving far beyond the traditional Open D. As the original description notes, it's an "extension of open D adds 9ths, 7ths, minors," creating a tuning rich with both major and minor harmonic possibilities. It leans into a sophisticated, almost jazz-inflected sound while retaining the open, resonant character typical of open tunings. Players will find this tuning inspiring for blues, jazz fusion, folk, and even modern ambient soundscapes, offering a full, lush chord when strummed open.

Technical Analysis

The Open D9 tuning on an 8-string guitar presents the following notes from lowest (String 8) to highest (String 1):

• String 8: D1 (Root, an exceptionally low pitch)
• String 7: A1 (Perfect 5th)
• String 6: D2 (Octave)
• String 5: F#3 (Major 3rd)
• String 4: A2 (Perfect 5th, a lower octave than String 5's root, adding depth)
• String 3: D3 (Octave)
• String 2: E3 (Major 9th / Major 2nd)
• String 1: C4 (Minor 7th)

When strummed open, these notes collectively form a powerful D9 chord (D-F#-A-C-E). The arrangement provides a wide, expansive voicing, starting from an exceptionally low D1 and reaching up to C4. The presence of the Major 3rd (F#), Minor 7th (C), and Major 9th (E) on open strings means that a single strum yields a complete, rich, dominant 9th chord. The multiple D and A notes (D1, D2, D3 and A1, A2) add significant depth and resonance to the open chord, creating a thick, sustained sound.

Chordal Possibilities

• Open Chord: The entire tuning is a magnificent D9 chord. This allows for immediate, rich harmonic textures without any fretting.
• Movable 9ths: By simply barring all strings at any given fret, you can easily transpose this D9 shape into other dominant 9th chords across the fretboard (e.g., bar at the 3rd fret for F9, 5th fret for G9, etc.).
• Implied Major/Minor/Altered: Fret the C (String 1) up a semitone to C# to get a Dmaj9. By judiciously muting or fretting certain strings, one could also imply D major, D minor, or explore altered dominant sounds by shifting the 7th or 9th.
• Unique Voicings: The unique intervallic spread, especially the F#3 followed by A2, creates interesting sonic possibilities for arpeggios, fingerstyle patterns, and melodic lines that are distinct from standard tuning. The robust low D1 and A1 strings provide a strong bass foundation for complex harmonic explorations.

How to Tune Your Guitar

To achieve the Open D9 tuning, precisely follow these string adjustments. Please note that several strings require significant adjustments, so proceed with caution. If tuning significantly up or down (more than 4 semitones), consider using a different string gauge to ensure proper tension, intonation, and to prevent potential damage to your instrument.

• String 8 (Lowest): Tune down 4 semitones to reach D1.
• String 7: Tune down 2 semitones to reach A1.
• String 6: Tune down 2 semitones to reach D2.
• String 5: Tune down 3 semitones to reach F#3.
• String 4: Tune down 5 semitones to reach A2. Caution: This is a significant drop in pitch; a different string gauge may be advised.
• String 3: Tune down 5 semitones to reach D3. Caution: This is a significant drop in pitch; a different string gauge may be advised.
• String 2: Tune down 7 semitones to reach E3. Warning: This is a very significant drop in pitch (a perfect 5th plus 2 semitones); a different string gauge is strongly advised.
• String 1 (Highest): Tune down 4 semitones to reach C4.

String 8: D1

String 7: A1

String 6: D2

String 5: F#3

String 4: A2

String 3: D3

String 2: E3

String 1: C4