The "Open C6 Sus" tuning transforms your guitar into a resonant soundscape, built upon the foundation of a C6 chord with a prominent suspended fourth. As described, this tuning facilitates the immediate availability of a fourth interval on an open string, adding a unique harmonic texture.

Verbal Analysis

This tuning offers a rich, full, and somewhat mellow sound, ideal for creating expansive chord voicings and melodic lines. The open strings, when strummed together, create an immediate sense of warmth and can evoke styles ranging from folk and acoustic blues to more contemporary fingerstyle compositions. It's particularly well-suited for slide guitar due to the open chord structure, allowing for fluid glissandos and expressive phrasing. The suspended fourth adds a contemplative or yearning quality, making it versatile for both introspective pieces and uplifting arrangements.

Technical Analysis

The open string notes are configured as C2 F2 G3 A3 C4 E4. This arrangement inherently forms a C6 chord (C-E-G-A) with an added F as a suspended fourth. Let's break down the intervals:

• String 6 (C2) acts as the root.
• String 5 (F2) is a perfect fourth above the root C, creating a strong sus4 flavour and providing a deep bass F.
• String 4 (G3) is a perfect fifth above the root C.
• String 3 (A3) is a major sixth above the root C, completing the C6 sonority.
• String 2 (C4) is an octave above the root C.
• String 1 (E4) is a major third above the root C.

The presence of the low F on the 5th string (F2) alongside the C (C2) on the 6th string creates a powerful perfect fourth interval, giving the tuning its unique character and the described "ability to play a fourth on an open string." This tuning is diatonic to C Major, making it easy to find melodic and harmonic ideas within that key.

Open Chords & Accessible Shapes:

• Strumming all open strings yields a full and resonant C6sus4 chord (C-F-G-A-C-E).
• Barring all strings at any fret will produce the corresponding 6sus4 chord up the neck (e.g., Fret 1 = C#6sus4, Fret 5 = F6sus4).
• Muting string 5 (F2) allows for a clear C6 chord to ring out (C-G-A-C-E).
• The strong interval of a perfect fourth (C-F) on the lowest two strings can be used for drone effects or powerful bass lines.
• Shapes for Fmaj7 and G7 chords may become surprisingly intuitive due to the presence of F and G notes in the open tuning.
• The open C and E on the top two strings (C4 E4) provide a readily available C major third, useful for lead melodies and adding harmonic colour.

How to Tune

To achieve the Open C6 Sus tuning from standard EADGBe, follow these steps:

• String 6 (Low E to C): Tune down 4 semitones. This is a significant drop, so proceed with care. Note: Tuning down 4 semitones (from E to C) is a substantial change. If your guitar normally uses light gauge strings, you might consider a heavier gauge set to maintain tension and avoid excessive slack.
• String 5 (A to F): Tune down 4 semitones. Another considerable drop, requiring attention to string tension. Note: Tuning down 4 semitones (from A to F) is a substantial change. If your guitar normally uses light gauge strings, you might consider a heavier gauge set to maintain tension and avoid excessive slack.
• String 4 (D to G): Tune up 5 semitones. This is a large increase in tension. Tune slowly and carefully. Note: Tuning up 5 semitones (from D to G) is a significant increase in tension. While possible, for long-term use or if your guitar uses very light gauge strings, a heavier gauge string or even a dedicated set for open tunings is strongly advised to prevent string breakage and potential neck damage. Proceed with extreme caution.
• String 3 (G to A): Tune up 2 semitones.
• String 2 (B to C): Tune up 1 semitone.
• String 1 (High E to E): Keep as is; no change (0 semitones).

Always use a reliable tuner and tune gradually to avoid over-tightening or sudden slackening, which can damage strings or your instrument.

String 6: C2 (Low C)

String 5: F2 (F an octave below middle C)

String 4: G3 (G below middle C)

String 3: A3 (A below middle C)

String 2: C4 (Middle C)

String 1: E4 (E above middle C)