The C Extended Open tuning transforms your guitar into a resonant soundscape, centered around a deep, grounding C note on the lowest string. This isn't your everyday major or minor open chord; it's a rich and complex voicing that invites exploration and offers unique harmonic possibilities.

Verbally, this tuning presents a dark, expansive, and somewhat sophisticated character. The open strings resonate with a broad, full sound, making it excellent for ambient soundscapes, progressive rock, jazz-infused compositions, or even metal genres seeking a weighty low C without sacrificing harmonic depth. It encourages players to think beyond traditional chord shapes and discover new fingerings that leverage the unique string relationships.

Technical Analysis:

The open strings are tuned to C2 G2 D3 F3 B3 D4 (low to high). From the root C, the intervals present are a Perfect 5th (G), a Major 9th (D), a Perfect 4th/11th (F), a Major 7th (B), and another Major 9th (D). This configuration closely resembles an extended C chord, specifically a Cmaj7 (C-G-B) with the addition of the 9th (D) and the 11th (F). The presence of the Major 7th (B) and Perfect 4th (F) creates a sophisticated, almost jazzy or Lydian-esque quality.

Chords that are readily accessible or implied by the open strings include:

• Open C Power Chord: By strumming strings 6, 5, and 4 (C-G-D), you get a powerful C5 chord, with the D adding an extra layer of fullness.
• Cmaj7/Cmaj9 Voicings: The C-G-B notes are present across strings 6, 5, and 2. Adding the D on strings 4 and 1 further enriches this into a Cmaj9. Simple barres can yield various C major and extended voicings.
• Fmaj7/C: The notes F, B, D on strings 3, 2, 1, when combined with the low C, suggest an Fmaj7 chord over a C bass, offering interesting harmonic textures.
• G Major Triad Fragment: The B3 and D4 on strings 2 and 1 are the major 3rd and perfect 5th of G major, allowing for easy G chord shapes in the higher register.

This tuning is highly conducive to drone-based playing and arpeggiated figures that highlight its rich harmonic content. Its unique structure encourages experimentation and the discovery of fresh musical ideas.

How to Tune to C Extended Open:

To achieve the C Extended Open tuning from standard E, follow these steps. Please use a reliable tuner. Note that significant string tension changes can occur; be mindful of your guitar's neck relief. When tuning strings down more than 4 semitones or up more than 3 semitones, it's generally advisable to consider a different string gauge to maintain optimal tension and tone.

• 6th String (Low E): Tune down 4 semitones from E2 to C2. (Note: Tuning down 4 semitones is a significant drop; lighter gauge strings may feel very loose, while heavier gauges might be required for optimal tension and tone.)
• 5th String (A): Tune down 2 semitones from A2 to G2.
• 4th String (D): Keep as is; no change (0 semitones). Remains at D3.
• 3rd String (G): Tune down 2 semitones from G3 to F3.
• 2nd String (B): Keep as is; no change (0 semitones). Remains at B3.
• 1st String (High E): Tune down 2 semitones from E4 to D4.