Verbal Analysis

Welcome to the distinct sound of Open C7 Tuning! This unique configuration, as described by its creator, opens up a world of bluesy, soulful, and resonant possibilities. With the open strings forming a C7 chord (C-G-C-E-G-A#), you immediately get a rich, full-bodied dominant seventh sound that's perfect for slide guitar, powerful strumming, or complex fingerstyle. The low C provides a deep, foundational bass, while the A# on the high string adds that characteristic, yearning dominant seventh tension. This tuning invites experimentation, providing a powerful harmonic canvas for improvisation and songwriting. It's a tuning that truly sings, allowing you to evoke everything from gritty delta blues to lush jazz voicings with ease.

Technical Analysis

This tuning transforms your standard guitar into a vibrant C7 chord when played open, with the notes arranged as C2-G2-C3-E3-G3-A4# (from low E to high E string).

Let's look at the intervals between the open strings:

• String 6 (C2) to String 5 (G2): Perfect 5th
• String 5 (G2) to String 4 (C3): Perfect 4th
• String 4 (C3) to String 3 (E3): Major 3rd
• String 3 (E3) to String 2 (G3): Minor 3rd
• String 2 (G3) to String 1 (A4#): Minor 7th (relative to C, this creates the dominant 7th tension)

The open C7 chord (C-G-C-E-G-A#) provides a strong harmonic base, making full dominant seventh chords instantly accessible. Because of the inherent C7 chord, you can achieve powerful blues and rock voicings simply by barring across all strings at a single fret. For example:

• Barring at the 1st fret yields a C#7 chord.
• Barring at the 3rd fret yields a D#7 (or Eb7) chord.
• Barring at the 5th fret yields an F7 chord.

Beyond simple barring, the tuning's interval structure makes certain shapes very accessible. For instance, the stacked perfect 5th and 4th on the low strings (C-G-C) are ideal for robust power chords and bass lines. The presence of the A# (minor 7th) on the high string means that raising it by one fret creates a B natural, which can lead to interesting Cmaj7#11 or C13 voicings, expanding the harmonic palette significantly.

Important Note on String Gauge

As correctly noted, this tuning involves significant downward movements for most strings from standard EADGBe. Specifically, the low E string (-4 semitones), B string (-4 semitones), and particularly the high E string (-6 semitones) are tuned down significantly. Tuning down this far can cause strings to feel floppy, result in poor intonation, and even make them prone to buzzing with standard gauge strings. It is strongly advised to use slightly heavier gauge strings, especially for the lower E, B, and high E strings, to maintain optimal tension, tone, and playability throughout the tuning range.

How to Tune

To achieve the Open C7 tuning from standard EADGBe (E2-A2-D3-G3-B3-E4), follow these string movements:

• String 6 (Low E): Tune down 4 semitones to C2.
• String 5 (A): Tune down 2 semitones to G2.
• String 4 (D): Tune down 2 semitones to C3.
• String 3 (G): Tune down 3 semitones to E3.
• String 2 (B): Tune down 4 semitones to G3.
• String 1 (High E): Tune down 6 semitones to A4#.

String 6: C2

String 5: G2

String 4: C3

String 3: E3

String 2: G3

String 1: A4#