Tuning Overview: Drop C Double Third for 9-String Guitar

The "Drop C Double Third" tuning for a 9-string Guitar is a powerful and harmonically rich setup designed for a broad sonic palette. As its name suggests, the lowest string is dropped to C, providing a deep, resonant foundation typical of heavy genres like metal, djent, and progressive rock. The "Double Third" aspect refers to the inclusion of two major third intervals between consecutive open strings, enhancing the harmonic possibilities and making certain chord voicings particularly vibrant.

Technical Analysis: Intervals and Open Chords

This tuning, from lowest to highest string (C1-G1-C2-F2-A2-D3-G3-B3-E4), presents an interesting blend of intervals:

• The lowest three strings (C1-G1-C2) form a powerful C5 power chord, ideal for heavy riffing and foundational bass lines.
• The intervals between strings are:
  • String 9 (C1) to String 8 (G1): Perfect 5th
  • String 8 (G1) to String 7 (C2): Perfect 4th
  • String 7 (C2) to String 6 (F2): Perfect 4th
  • String 6 (F2) to String 5 (A2): Major 3rd (one of the "double thirds")
  • String 5 (A2) to String 4 (D3): Perfect 4th
  • String 4 (D3) to String 3 (G3): Perfect 4th
  • String 3 (G3) to String 2 (B3): Major 3rd (the second "double third")
  • String 2 (B3) to String 1 (E4): Perfect 4th

This configuration allows for several open string harmonies and easily reachable chords:

• The trio of strings 4, 3, and 2 (D3-G3-B3) form an open G Major triad (second inversion), making G major chords very resonant.
• Similarly, strings 3, 2, and 1 (G3-B3-E4) form an open E Minor triad (second inversion), providing an accessible minor tonality.
• The presence of the two major third intervals (F2-A2 and G3-B3) facilitates smooth voicings of major chords and arpeggios that include these intervals.
• The sequence of perfect fourths in the middle/upper strings (A2-D3, D3-G3, B3-E4) retains some familiarity for players accustomed to standard tuning, allowing for transferable scale and chord shapes in those regions.

How to Tune: Adjusting Your 9-String

To achieve the "Drop C Double Third" tuning, carefully adjust your strings according to the following movements. It is always recommended to use a reliable digital tuner.

• String 9 (Lowest): Tune down 1 semitone to C1.
• String 8: Tune up 1 semitone to G1.
• String 7: Tune up 1 semitone to C2.
• String 6: Tune up 1 semitone to F2.
• String 5: Keep as is; no change (0 semitones) to A2.
• String 4: Keep as is; no change (0 semitones) to D3.
• String 3: Keep as is; no change (0 semitones) to G3.
• String 2: Keep as is; no change (0 semitones) to B3.
• String 1 (Highest): Keep as is; no change (0 semitones) to E4.

Important Note on String Gauge: When tuning strings significantly (e.g., more than 4 semitones up or down), it is generally advisable to consider using a different string gauge to maintain proper tension and avoid potential damage to your instrument or strings. For this particular tuning, all movements are within a single semitone, making it generally safe for standard gauge strings.

Here are the notes for each string, from the lowest (thickest) to the highest (thinnest):

• String 9 (Lowest): C1
• String 8: G1
• String 7: C2
• String 6: F2
• String 5: A2
• String 4: D3
• String 3: G3
• String 2: B3
• String 1 (Highest): E4