The Open Cmaj9 (CGDEBD) tuning is a harmonically rich and evocative setup for the guitar, particularly well-suited for fingerstyle playing and creating lush, complex chord voicings with remarkable ease. This tuning transforms your guitar into an instrument that, when strummed open, immediately resonates with a full C major ninth chord (C-E-G-B-D), offering a sophisticated sound right out of the box.

Verbal Analysis

This tuning invites exploration and improvisation. The inherent Cmaj9 chord creates a wide, open sound that is both bright and melancholic, perfect for atmospheric pieces, ballads, or jazz-inflected compositions. Players will find that melodic lines played on individual strings will naturally harmonize with the underlying Cmaj9, making it easy to weave intricate musical tapestries. The spacing of the notes across the strings feels intuitive for arpeggios and sustained drones, allowing for a full, piano-like texture.

Technical Analysis

Based on a standard EADGBe tuning, the Open Cmaj9 tuning involves significant alterations to four of the six strings. The notes are tuned to C2-G2-D3-E3-B3-D4. The intervals between adjacent strings are:

• 6th (C2) to 5th (G2): Perfect 5th (7 semitones)
• 5th (G2) to 4th (D3): Perfect 5th (7 semitones)
• 4th (D3) to 3rd (E3): Major 2nd (2 semitones)
• 3rd (E3) to 2nd (B3): Perfect 4th (5 semitones)
• 2nd (B3) to 1st (D4): Minor 3rd (3 semitones)

This unique set of intervals means that traditional chord shapes will not translate directly, requiring a fresh approach to the fretboard. However, this also unlocks a wealth of new sonic possibilities.

Open Chords and Possibilities

Beyond the obvious open Cmaj9, this tuning offers several easy-to-reach chordal ideas:

• Open Cmaj9: All strings played open. This is the defining characteristic of the tuning.
• Barre Chords: A full barre across any fret will instantly produce a major ninth chord corresponding to the root note at that fret on the 6th string. For example, a barre at the 2nd fret would yield an open Dmaj9 chord.
• Root-5th Bass: The lowest two strings (C2-G2) form a perfect fifth, making it easy to create strong, resonant power chords by simply fretting these two strings.
• Cluster Voicings: The D3-E3 (4th and 3rd strings) form a major second, which can be exploited for interesting, tight voicings or suspended sounds.
• Cmaj7: By muting or avoiding the 1st string (D4), you can approximate a Cmaj7 sound with a strong C-G-D-E-B voicing.

This tuning is an excellent choice for players looking to break away from conventional sounds and explore new harmonic landscapes, particularly those who appreciate the richness of extended chords and the freedom of open string resonances.

Tuning Notes

• 6th String (Low E): C2
• 5th String (A): G2
• 4th String (D): D3
• 3rd String (G): E3
• 2nd String (B): B3
• 1st String (High E): D4

How to Tune Your Guitar to Open Cmaj9 (CGDEBD)

To achieve the Open Cmaj9 (CGDEBD) tuning, you will need to adjust several strings from standard EADGBe tuning. Please tune your strings carefully, using a reliable tuner.

• 6th String (Low E): Tune down 4 semitones from E2 to C2. Caution: Tuning down 4 semitones is a significant drop. If this tuning is used frequently, consider a heavier gauge string to maintain tension and tone.
• 5th String (A): Tune down 2 semitones from A2 to G2.
• 4th String (D): Keep as is; no change (0 semitones) from D3 to D3.
• 3rd String (G): Tune down 3 semitones from G3 to E3.
• 2nd String (B): Keep as is; no change (0 semitones) from B3 to B3.
• 1st String (High E): Tune down 2 semitones from E4 to D4.

Always double-check your tuning after all strings have been adjusted, as changes to one string can affect the tension and pitch of others.