This is a highly unique and expansive open tuning for guitar, offering a bright and complex sonic palette. Derived from the original "GUIDE DOG 2" concept, it appears to be an experimental tuning designed to open up new harmonic possibilities, moving beyond conventional open chord tunings.

Technical Analysis

The open strings are tuned to D2 B2 E3 A3 C#4 E4 (from lowest to highest string). This configuration results in a sound strongly reminiscent of an extended D Major chord. When analyzed from the lowest D string, the intervals are: Root (D), Major 6th (B), Major 2nd/9th (E), Perfect 5th (A), Major 7th (C#), and an octave higher Major 2nd/9th (E). This collection of notes (D, E, A, B, C#) is a subset of a D Major 13th chord (D, F#, A, C#, E, G, B), with the F# (Major 3rd) being an implied note that can be easily added by fretting. The tuning is not a simple chord, but rather a rich harmonic cluster designed for evocative textures and advanced voicings.

Chords and Playability

The open strings themselves resonate to form a compelling D Major 13th sound, making it ideal for drone passages, ambient soundscapes, or fingerstyle playing where these rich voicings can ring out. The absence of the Major 3rd (F#) in the open tuning provides a certain ambiguity, allowing for both major and sometimes more modal qualities depending on how you play. Simple one-finger movements or partial fretting can unlock many chords:

• Fretting the 4th string (E) at the 2nd fret will yield F#, completing a full D Major chord with extended voicings.
• Barre chords become powerful tools, allowing for easy transposition of this extended voicing across the fretboard, creating dense and complex harmony with minimal effort.
• The wide intervals on the lower strings (D2 B2 E3) offer unique melodic opportunities, perfect for arpeggios and phrases that stand out from conventional tunings.
• Experimenting with slides and sustained notes will yield lush, evolving textures due to the inherent harmonic richness.

How to Tune

To achieve the D Major 13th Open Tuning from standard E Standard tuning (E2 A2 D3 G3 B3 E4), follow these instructions carefully:

• 6th String (Low E): Tune down 2 semitones from E2 to D2. This is a common drop tuning, offering a deep, resonant low end.
• 5th String (A): Tune up 2 semitones from A2 to B2. Exercise care when raising string tension.
• 4th String (D): Tune up 2 semitones from D3 to E3. Exercise care when raising string tension.
• 3rd String (G): Tune up 2 semitones from G3 to A3. Exercise care when raising string tension.
• 2nd String (B): Tune up 2 semitones from B3 to C#4. Exercise particular care when raising string tension. While the original tuning notes listed C#5, the movement instruction strictly indicates a 2-semitone increase from B3, resulting in C#4. This is a significant but manageable tension increase.
• 1st String (High E): Keep as is; no change (0 semitones). It remains E4.

Important Note: All upward string movements in this tuning are 2 semitones. While this does not exceed the threshold of 4 semitones where a different string gauge is typically advised, it is always crucial to tune up slowly and carefully to prevent string breakage and ensure string stability. The -2 semitone drop on the 6th string is well within standard string capabilities.

6th String: D2 (tuned down 2 semitones from standard E)

5th String: B2 (tuned up 2 semitones from standard A)

4th String: E3 (tuned up 2 semitones from standard D)

3rd String: A3 (tuned up 2 semitones from standard G)

2nd String: C#4 (tuned up 2 semitones from standard B)

1st String: E4 (no change from standard high E string)