The "F6/9... Sun Eater" tuning is a unique and powerful setup for an 8-string guitar, designed for players seeking a heavy yet clear sound, actively avoiding the muddiness often associated with extreme drop tunings. As described by its creator, this tuning aims to provide a robust low 'A1' while distinctly retaining a 'G' string, making it ideal for a strong, defined presence in a band setting where a heavy, punchy sound is paramount. It prioritizes clarity and tightness over the loose feel of very low drop tunings, contributing to a more articulate and impactful tone.

Technical Analysis

• The open strings are tuned to: A1-D2-G2-C3-F3-A3-D4-G4 (from lowest to highest).
• The interval structure is predominantly based on Perfect Fourths (P4), offering a logical and consistent layout across most of the fretboard. The full breakdown is as follows:
  • String 8 (A1) to String 7 (D2): Perfect 4th (5 semitones)
  • String 7 (D2) to String 6 (G2): Perfect 4th (5 semitones)
  • String 6 (G2) to String 5 (C3): Perfect 4th (5 semitones)
  • String 5 (C3) to String 4 (F3): Perfect 4th (5 semitones)
  • String 4 (F3) to String 3 (A3): Major 3rd (4 semitones) – this is a crucial deviation from a pure all-fourths tuning, introducing a familiar interval found in standard guitar tuning that facilitates common chord shapes.
  • String 3 (A3) to String 2 (D4): Perfect 4th (5 semitones)
  • String 2 (D4) to String 1 (G4): Perfect 4th (5 semitones)
• The consistent Perfect Fourth intervals (P4) across most strings make horizontal fretboard navigation highly predictable, simplifying the transposition of scales and arpeggio patterns. This design promotes a fluid playing style, especially for complex runs and leads. The inclusion of the Major 3rd (M3) break between strings 4 and 3 allows for the adaptation of many standard guitar chord voicings, blending the benefits of an all-fourths system with traditional chordal possibilities.

Open Chords and Harmonic Possibilities

• When all open strings are strummed, the notes A, D, G, C, F, A, D, G combine to form a rich and complex extended chord. This harmony can be identified as an F6/9sus4 chord (F, A, C, D, G, with additional octaves), providing a deep, full, and intriguing harmonic foundation for compositions.
• More simply, the open strings directly yield an F Major triad (F, A, C) across strings 5, 4, and 3 (C3, F3, A3) and an open D minor triad (D, F, A) across strings 7, 4, and 3 (D2, F3, A3), allowing for immediate harmonic content without fretting.
• The predominantly Perfect Fourth intervals facilitate extremely easy formation of power chords. By simply barring two adjacent strings at the same fret (e.g., strings 8 & 7, 7 & 6, etc.), players can effortlessly create powerful two-note or three-note (Root-5th-Octave) power chords that can be moved consistently across the fretboard, ideal for heavy riffing and chord progressions.
• Due to the structured nature of the tuning, many jazz and modern chord voicings become highly accessible. Patterns are largely consistent across the Perfect Fourth sections of the neck, enabling complex harmonies to be formed and moved with ease, opening up diverse harmonic and melodic explorations.

String 8 (Lowest): A1

String 7: D2

String 6: G2

String 5: C3

String 4: F3

String 3: A3

String 2: D4

String 1 (Highest): G4

How to Tune

To achieve the "F6/9... Sun Eater" tuning, start from your guitar's current tuning and adjust each string as follows. Please exercise caution when tuning strings up, as excessive tension can lead to string breakage or neck damage. While none of the string movements technically exceed the threshold of 4 semitones where a different gauge is strongly advised, movements of 3 semitones are significant and should be done carefully, monitoring string tension closely.

• String 8 (A1): Tune up 3 semitones. (Note: Tuning up 3 semitones is a significant adjustment. Proceed with care and ensure your strings and instrument can handle the increased tension.)
• String 7 (D2): Tune up 3 semitones. (Note: Tuning up 3 semitones is a significant adjustment. Proceed with care and ensure your strings and instrument can handle the increased tension.)
• String 6 (G2): Tune up 3 semitones. (Note: Tuning up 3 semitones is a significant adjustment. Proceed with care and ensure your strings and instrument can handle the increased tension.)
• String 5 (C3): Tune up 3 semitones. (Note: Tuning up 3 semitones is a significant adjustment. Proceed with care and ensure your strings and instrument can handle the increased tension.)
• String 4 (F3): Tune up 3 semitones. (Note: Tuning up 3 semitones is a significant adjustment. Proceed with care and ensure your strings and instrument can handle the increased tension.)
• String 3 (A3): Tune up 2 semitones. (This is a moderate adjustment and generally safe for standard string gauges.)
• String 2 (D4): Tune up 3 semitones. (Note: Tuning up 3 semitones is a significant adjustment. Proceed with care and ensure your strings and instrument can handle the increased tension.)
• String 1 (G4): Tune up 3 semitones. (Note: Tuning up 3 semitones is a significant adjustment. Proceed with care and ensure your strings and instrument can handle the increased tension.)