The "Perfect 4th 9 String Tuning" is a distinctive setup for a 9-string guitar, designed to offer a unique sonic landscape and playability. While its name suggests an all-fourths interval structure, a technical analysis reveals a more complex and varied arrangement of intervals between strings.

Verbal Analysis

This tuning presents a fascinating challenge and opportunity for exploration. The presence of several perfect fourths (C#2-F#2, B1-E2, G#3-C#4-F#4, B3-E4) across the strings creates familiar patterns for players accustomed to bass-like or all-fourths tunings, allowing for easy movable chord shapes and melodic runs within these segments. However, the tuning is punctuated by significant deviations: two descending perfect fifths (F#2-B1 and F#4-B3) and a compound major third (E2-G#3), which is a Major 3rd plus an octave. This wide interval creates a dramatic shift in register.

The large octave jump between E2 and G#3 offers a wide dynamic range for arpeggios and unique voicings that span a vast interval. The descending perfect fifths, while breaking the consistent fourths pattern, can open up unexpected resonant open string voicings or facilitate specific bass-note runs. Players will find that traditional chord shapes may need re-learning or adaptation across these irregular intervals, but this also encourages new harmonic and melodic approaches.

While the open strings themselves do not form a single common chord, subsets of the tuning can imply various harmonies. For example, the segment E2-G#3-B3-E4 clearly outlines an E major chord. The combination of C#2, F#2, and G#3 could form a C#sus4 type of voicing. This tuning is excellent for creating dense, complex soundscapes, or for metal and progressive genres that utilize extended range and unique harmonic structures. It encourages creative fingerings and rewards a player willing to break from conventional patterns.

Technical Analysis

• Overall Range: From the lowest C#2 to the highest E4, this 9-string tuning covers an expansive range of over three octaves (approximately 37 semitones).
• Interval Breakdown (from lowest to highest string):
  • String 9 (C#2) to String 8 (F#2): Perfect 4th (5 semitones)
  • String 8 (F#2) to String 7 (B1): Descending Perfect 5th (-7 semitones)
  • String 7 (B1) to String 6 (E2): Perfect 4th (5 semitones)
  • String 6 (E2) to String 5 (G#3): Compound Major 3rd (Major 3rd + Octave, 16 semitones)
  • String 5 (G#3) to String 4 (C#4): Perfect 4th (5 semitones)
  • String 4 (C#4) to String 3 (F#4): Perfect 4th (5 semitones)
  • String 3 (F#4) to String 2 (B3): Descending Perfect 5th (-7 semitones)
  • String 2 (B3) to String 1 (E4): Perfect 4th (5 semitones)
• Harmonic Implications: The repeated Perfect 4th segments create a foundation for linear playing and power chords. The two P5th drops and the M3+Octave jump introduce unique harmonic possibilities, forcing players to adapt and discover new chord voicings and arpeggio patterns.

How to Tune

To achieve the "Perfect 4th 9 String Tuning", follow these precise string adjustments from a reference point (e.g., standard tuning or previous setup). Remember to always tune carefully, especially when adjusting pitch.

• String 9 (C#2): Keep as is; no change (0 semitones).
• String 8 (F#2): Keep as is; no change (0 semitones).
• String 7 (B1): Keep as is; no change (0 semitones).
• String 6 (E2): Keep as is; no change (0 semitones).
• String 5 (G#3): Tune down 1 semitone.
• String 4 (C#4): Tune down 1 semitone.
• String 3 (F#4): Tune down 1 semitone.
• String 2 (B3): Keep as is; no change (0 semitones).
• String 1 (E4): Keep as is; no change (0 semitones).

All adjustments are within a small range (0 or -1 semitones), so a change in string gauge is generally not necessary for this tuning.

The notes for this 9-string guitar tuning are:

• String 9 (Lowest): C#2
• String 8: F#2
• String 7: B1
• String 6: E2
• String 5: G#3
• String 4: C#4
• String 3: F#4
• String 2: B3
• String 1 (Highest): E4