Overview

The Open Cadd9 Tuning, often discovered through creative exploration, transforms your guitar into a deeply resonant and harmonically rich instrument. With all open strings forming a Cadd9 chord (C-G-C-G-E-D), it provides a full, shimmering sound perfect for immediate strumming or intricate fingerstyle passages. This tuning lends itself well to folk, acoustic rock, contemporary, and ambient genres, offering a unique sonic landscape for composers and players alike.

Technical Breakdown

From the lowest to the highest string, the notes are C2-G2-C3-G3-E4-D4. This specific arrangement of notes directly outlines a Cadd9 chord. Let's examine the intervals relative to the root note C:

• 6th String (C2): Functions as the primary root of the chord.
• 5th String (G2): Provides the perfect fifth, adding stability and depth.
• 4th String (C3): An octave above the root, reinforcing the fundamental.
• 3rd String (G3): An octave above the perfect fifth, further enriching the harmonic texture.
• 2nd String (E4): Delivers the major third, giving the chord its major quality.
• 1st String (D4): Introduces the major ninth, which is characteristic of the 'add9' extension, adding brightness and harmonic complexity to the C major triad.

The tuning's structure, with repeated Cs and Gs across the lower strings, creates a powerful drone effect, while the higher E and D notes provide the chordal color and sparkle. The broad range from C2 to D4 makes it versatile for both robust rhythm work and delicate melodic phrases.

Chordal Opportunities

The most immediate benefit of Open Cadd9 tuning is that simply strumming all open strings produces a full, beautiful Cadd9 chord. Beyond this, many common chord shapes become surprisingly accessible or take on new, interesting voicings:

• Barre Chords: Barring across any fret will instantly yield a corresponding Add9 chord (e.g., barring at the 2nd fret creates a Dadd9, 3rd fret an Ebadd9, etc.), making transposing simple.
• G Major/Gadd9: Due to the prevalence of G notes, G major and Gadd9 chords are often easily formed with minimal fretting, especially on strings 5, 3, and 1.
• F Major/Fadd9: By shifting the Cadd9 open position shape, or by utilizing the strong C-G-C foundation on the lower strings, F major variations can be found with relative ease.
• Suspended Chords: The presence of the D (9th) can often be easily manipulated to create sus2 or sus4 voicings on other roots, offering unique melodic opportunities.
• Minor Chords: To achieve a C minor chord, the 2nd string (E4) would need to be flattened to Eb4. This could be done by fretting the 2nd string at the 3rd fret, or by tuning it down an additional semitone from its current E4.

This tuning invites players to explore and discover new chord shapes and voicings that might be challenging or impossible in standard tuning, encouraging a fresh approach to songwriting and improvisation.

How to Tune (from Standard EADGBe)

Please be aware that string movements exceeding -4 or +4 semitones can significantly alter string tension. For optimal playability and to prevent string breakage, consider using different string gauges as advised for these strings.

• 6th String (Original E2): Tune down 4 semitones to C2.
  Note: Tuning down 4 semitones is a significant change. Consider using a heavier gauge string for the 6th string to maintain optimal tension and tone.
• 5th String (Original A2): Tune down 2 semitones to G2.
• 4th String (Original D3): Tune down 2 semitones to C3.
• 3rd String (Original G3): Keep as is; no change (0 semitones) to G3.
• 2nd String (Original B3): Tune up 5 semitones to E4.
  Note: Tuning up 5 semitones is a significant change. Consider using a lighter gauge string for the 2nd string to avoid excessive tension and potential string breakage.
• 1st String (Original E4): Tune down 2 semitones to D4.