This is the "Double Drop A" tuning for a 9-string guitar, inspired by Andrew Baena's interpretation of an Emmure breakdown. It's designed for maximum low-end impact and rhythmic aggression, perfect for modern metal, djent, and hardcore.

Verbal Analysis

Verbally, this tuning plunges into the deepest registers, creating an incredibly thick and resonant foundation. The "Double Drop A" implies that not just the lowest string, but also other key strings, are brought down to A or related notes, creating a unique sonic landscape. It's built for heavy riffing, chugging, and open-string percussive attacks, where clarity at extreme low frequencies is paramount. This tuning fosters a sense of immense weight and dark power, ideal for generating crushing breakdowns and formidable low-end rhythms.

Technical Analysis

This 9-string tuning presents the following open notes, from the thickest (9th string) to the thinnest (1st string): A0 E1 A1 D2 G2 C3 F3 A3 D4.

• The foundational string is an astonishing A0, providing an earth-shattering low end that is two full octaves below standard A2 on a 6-string guitar.
• The lowest three strings (A0, E1, A1) form a massive A5 (power chord) voicing when played open. This is the hallmark of a "Drop A" configuration, extended across three strings for immense depth and immediate power chord accessibility.
• From the 7th string (A1) upwards to the 3rd string (F3), the tuning largely follows a pattern of perfect fourths (A1-D2, D2-G2, G2-C3, C3-F3). This consistent interval makes power chords and scale shapes highly intuitive across these strings, similar to the middle strings of a standard-tuned guitar.
• An interesting deviation occurs between the 3rd string (F3) and 2nd string (A3), which is a major third interval. This interval adds a different harmonic flavor and provides opportunities for specific chord voicings or melodic lines that deviate from the perfect fourths.
• The highest string (D4) is a perfect fourth above the 2nd string (A3).
• The tuning features multiple octaves of A (A0, A1, A3) and D (D2, D4) across the instrument, creating a rich harmonic resonance for the key of A or D, making it powerful for compositions in those keys or modes.

Open Chords and Accessibility

• The most immediate and powerful open chord is the A5 power chord achievable on strings 9, 8, and 7 (A0-E1-A1). This three-note open voicing is exceptionally thick and forms the core of its breakdown potential.
• Due to the prevalence of perfect fourths in the middle strings, standard two-finger power chords (root and fifth) or barre chords (root, fifth, octave) are easily formed by barring a single fret across adjacent strings.
• The A0 and A1 strings, along with D2 and D4, provide a strong tonal center. With the addition of the E1 (a perfect fifth above A0 and a perfect fourth below A1), simple A minor or major triad shapes become readily available with minimal effort on the open strings or low frets, providing a full, resonant sound.
• The F3-A3 major third interval on the higher strings can be used to form unique open F major or A minor chords with other strings, offering melodic contrast to the heavier lower register.
• This tuning is perfectly suited for one-finger octave riffs on the lower strings, leveraging the A0, A1, and D2, D4 relationships, making intricate low-end patterns very accessible.

Tuning Notes & How to Tune

Here are the target notes for each string, followed by instructions on how to adjust your guitar.

Target Tuning Notes:

• String 9 (Lowest): A0
• String 8: E1
• String 7: A1
• String 6: D2
• String 5: G2
• String 4: C3
• String 3: F3
• String 2: A3
• String 1 (Highest): D4

How to Tune:

Please proceed with caution, especially when tuning strings significantly up or down. For movements exceeding 4 semitones (up or down), a different gauge string is generally advised to maintain string tension and prevent damage to your instrument or strings.

• String 9 (A0): Tune down 4 semitones to A0. (Caution: Tuning down exactly 4 semitones is at the threshold where a different string gauge might be advised for optimal tension and playability.)
• String 8 (E1): Tune down 2 semitones to E1.
• String 7 (A1): Tune down 2 semitones to A1.
• String 6 (D2): Tune down 2 semitones to D2.
• String 5 (G2): Tune down 2 semitones to G2.
• String 4 (C3): Tune down 2 semitones to C3.
• String 3 (F3): Tune down 2 semitones to F3.
• String 2 (A3): Tune down 2 semitones to A3.
• String 1 (D4): Tune down 2 semitones to D4.