This tuning offers a highly unique and resonant soundscape for your guitar. It deviates significantly from standard tuning, creating an open A diminished 7th chord. The most striking feature is its "re-entrant" nature: the higher strings (1st and 2nd) are actually tuned to pitches lower than the middle strings (3rd and 4th), which is reminiscent of instruments like the ukulele or mandolin, but applied to the guitar's larger range. This arrangement can produce lush, drone-like qualities and allows for unusual melodic and harmonic possibilities, making it ideal for experimental music, blues, jazz, or creating atmospheric textures. Be prepared for a very different feel on the strings, especially the higher ones, which will be significantly slacker than usual.

Technical Analysis

• Open Notes: The open string notes are (from lowest to highest string): A1 - C2 - D#3 - F#3 - A2 - C3.
• Open Chord: When strummed open, these notes collectively form an A diminished 7th chord (A-C-D#-F#), with the root (A) and third (C) repeated at different octaves across the instrument.
• Re-Entrant Structure: The tuning is re-entrant, meaning the pitch does not strictly ascend from the lowest to the highest string. Specifically, String 2 (A2) and String 1 (C3) are lower in pitch than String 4 (D#3) and String 3 (F#3). This creates a unique voicing and melodic potential.

Accessible Chords & Playing Style

• Diminished Harmony: Strumming all open strings yields a full A diminished 7th chord. Due to the symmetrical nature of diminished 7th chords, this open voicing can be easily transposed by sliding a single finger or barre up the neck to quickly achieve C diminished 7th, D# diminished 7th, and F# diminished 7th chords.
• Drone & Melodic Potential: The re-entrant layout and open diminished harmony lend themselves well to drone-based playing, fingerstyle arrangements with complex inner voices, and exploring exotic scales. Standard chord shapes will require significant re-learning and adaptation.
• A Minor/A Major: While the open tuning is diminished, the presence of the root A and its minor third C, along with repeated A notes, can facilitate the creation of A minor or even A major (by fretting C to C#) voicings with careful finger placement.

How to Tune

To achieve the "A Diminished 7th Re-Entrant" tuning, please adjust each string from its current state according to the instructions below. Use a reliable tuner to ensure accuracy.

• String 6: Tune down 2 semitones to reach A1.
• String 5: Tune down 4 semitones to reach C2. Note: This is a significant drop. Consider a heavier gauge string for optimal tension and tone.
• String 4: Tune down 6 semitones to reach D#3. Warning: This is a substantial drop. A heavier gauge string is highly recommended to maintain proper tension and avoid string flop.
• String 3: Tune down 8 semitones to reach F#3. Warning: This is a very significant drop. A much heavier gauge string is strongly advised for playability and to prevent issues.
• String 2: Tune down 10 semitones to reach A2. Warning: This is an extreme drop. A much heavier gauge string is essential for this string to be playable and to avoid potential issues.
• String 1: Tune down 11 semitones to reach C3. Warning: This is a very extreme drop. A significantly heavier gauge string is absolutely necessary for this string. Proceed with caution.