The 'ZD tuning' is an exceptionally distinctive and highly customized tuning designed for a 7-string guitar. It presents a very broad tonal range and incorporates multiple re-entrant intervals, meaning that some strings are tuned to a lower pitch than the adjacent, typically lower-pitched, strings. This non-linear arrangement offers a unique sonic texture, moving away from conventional guitar tunings and encouraging a fresh approach to playing.

Technical Analysis

• Instrument Type: 7-String Guitar
• Open Notes (from lowest to highest string): F#2, C#3, G#3, C#4, B3, C#5, E4

A detailed look at the intervals between adjacent strings reveals the tuning's unconventional nature:

• String 7 (F#2) to String 6 (C#3): Perfect 5th (7 semitones up)
• String 6 (C#3) to String 5 (G#3): Perfect 5th (7 semitones up)
• String 5 (G#3) to String 4 (C#4): Perfect 4th (5 semitones up)
• String 4 (C#4) to String 3 (B3): Minor 2nd down (B3 is 1 semitone lower than C#4). This is a significant re-entrant interval.
• String 3 (B3) to String 2 (C#5): Major 9th up (14 semitones up). This is a substantial leap in pitch, spanning over an octave.
• String 2 (C#5) to String 1 (E4): Minor 7th down (E4 is 9 semitones lower than C#5). Another notable re-entrant interval.

Chordal and Harmonic Implications

The 'ZD tuning' is not designed for easy strumming of standard open chords. The combination of perfect fifths/fourths on the lower strings (F#2, C#3, G#3, C#4) provides a solid, resonant foundation, rich in power chord potential. However, the subsequent re-entrant strings (B3, C#5, E4) introduce unique tensions and wide voicings.

The open strings, when considering their pitch classes (F#, G#, B, C#, E), lean towards a modal sound, particularly reminiscent of F# Dorian (F# G# A B C# D E) or F# Natural Minor with specific extensions. It can evoke complex, open voicings like F#m7(add9,11) or C#sus2/F#. Players can explore unique arpeggios and intricate melodic lines, leveraging the extreme pitch differences and wide intervals between strings. This tuning is ideal for experimental music, specific riff construction, or creating a deeply resonant, dark, and harmonically rich soundscape.

How to Tune Your Guitar to ZD Tuning

Follow these instructions carefully to tune your 7-string guitar to the 'ZD tuning'. Take particular care with strings requiring larger semitone adjustments.

• String 7 (Lowest String): Tune to F#2. Keep as is; no change (0 semitones).
• String 6: Tune to C#3. Tune down 3 semitones.
• String 5: Tune to G#3. Tune down 1 semitone.
• String 4: Tune to C#4. Tune down 1 semitone.
• String 3: Tune to B3. Tune up 4 semitones.

  ⚠️ Caution: Tuning up 4 semitones is a significant adjustment. Please proceed with care to avoid string breakage. For optimal tension and safety, considering a different gauge string for this position is advised.

• String 2: Tune to C#5. Tune up 2 semitones.
• String 1 (Highest String): Tune to E4. Keep as is; no change (0 semitones).