The "G7sus4" tuning is an interesting open tuning that uniquely bridges the world of bass and guitar. It originated on a 4-string fretless bass and has been thoughtfully adapted for the guitar, specifically by extending its range with the addition of the high C4 and D4 strings.

Verbal Analysis: The Soundscape

When strummed open, this tuning immediately presents a rich, resonant G7sus4 chord. The sonic character is full and harmonically intriguing, with a strong root (G2, D2), a prominent suspended 4th/11th (C3, C4), and the distinctive flat 7th (F3). The addition of the high D4 provides a bright, ringing fifth, reinforcing the G tonality and adding shimmer. This tuning lends itself to atmospheric soundscapes, jazz-fusion explorations, and modern compositions where complex, yet pleasing, open voicings are desired. It has a slightly melancholic, yet vibrant, quality that evokes a sense of contemplative exploration.

Technical Analysis: Structure and Possibilities

Technically, the tuning is structured as D2-G2-C3-F3-C4-D4. This configuration creates a striking set of intervals:

• Strings 6-5 (D2-G2): Perfect 4th
• Strings 5-4 (G2-C3): Perfect 4th
• Strings 4-3 (C3-F3): Perfect 4th
• Strings 3-2 (F3-C4): Perfect 5th
• Strings 2-1 (C4-D4): Major 2nd

The prevalence of Perfect 4ths on the lower strings (D-G-C-F) creates a very consistent and intuitive fretboard layout for power chords and barres. Sliding a single finger across these lower four strings at any fret will always produce a consistent interval pattern, making it easy to transpose the open G7sus4 chord. For instance, barring at the 2nd fret yields an A7sus4, and at the 5th fret a D7sus4. The subsequent Perfect 5th (F3-C4) and Major 2nd (C4-D4) on the higher strings break this pattern, introducing unique melodic and harmonic possibilities, allowing for interesting counter-melodies and chord extensions not easily found in standard tuning. The open string arrangement strongly outlines the G7sus4 chord, making it an excellent base for improvisation and composition in the keys of G, C, or F.

Tuning Notes:

String 6 (Low E): D2
String 5 (A): G2
String 4 (D): C3
String 3 (G): F3
String 2 (B): C4
String 1 (High E): D4

How to Tune:

To achieve the G7sus4 tuning from standard EADGBe, follow these precise string adjustments:

• String 6 (Low E to D2): Tune down 2 semitones.
• String 5 (A to G2): Tune down 2 semitones.
• String 4 (D to C3): Tune down 2 semitones.
• String 3 (G to F3): Tune down 2 semitones.
• String 2 (B to C4): Tune up 1 semitones.
• String 1 (High E to D4): Tune down 2 semitones.

Important Note on String Tension: When tuning, please be mindful of the string movements. While most strings are tuned down by a moderate amount, string 2 is tuned up by 1 semitones. For tunings that require movements of more than 4 semitones up or down, it is generally recommended to consider a different string gauge to avoid potential string breakage or adverse effects on neck tension.