This is the incredibly deep and resonant "Drop A#/Drop Bb" tuning, an extreme detuning strategy that effectively shifts the entire guitar down by two full steps from a standard Drop D setup. It's designed for a heavy, guttural sound, making it a favorite among musicians in metal, deathcore, and djent genres who seek to explore the lowest sonic registers.

Technical Analysis:

• The open strings are tuned to A#2, F2, A#3, D#4, G3, C4, listed from the thickest (6th) to the thinnest (1st) string.
• The most prominent feature is the "Drop" configuration on the lowest three strings: A#2 (6th), F2 (5th), and A#3 (4th). When strummed open, these strings form a powerful A#5 (A# power chord), allowing for easy one-finger power chords across these strings.
• This tuning exhibits a significant re-entrant characteristic on the higher strings. Specifically, the 2nd string (G3) is tuned lower than the 3rd string (D#4). This unusual interval relationship (a minor 3rd between D#4 and G3, where D#4 is higher in pitch) will dramatically alter chord voicings and scale shapes, opening up unique harmonic possibilities but requiring adaptation from standard guitar playing techniques.
• Overall, this is a very low tuning, pushing the guitar into baritone territory. The substantial drop in pitch across all strings will result in significantly reduced string tension compared to standard tuning. To maintain playability, intonation, and prevent fret buzz, a much heavier gauge of strings (e.g., a baritone string set) is highly recommended.

Open Chords and Possibilities:

• A# Power Chord: The open 6th, 5th, and 4th strings provide a ready-to-play A#5 power chord. This shape can be easily moved up and down the neck with a single finger to form other power chords (e.g., fretting all three at the 1st fret gives a B5, 2nd fret a C5, etc.).
• Due to the extreme detuning and the re-entrant 2nd string, conventional open major/minor chords are not immediately available. However, the unique intervals encourage experimental voicings, dissonances, and complex harmonies often desired in modern heavy music.
• The low A# provides an incredibly solid foundation for heavy riffs, chugging, and drone notes.

Target Notes:

Here are the target notes for each string, from the thickest (6th) to the thinnest (1st):

• 6th String: A2#
• 5th String: F2
• 4th String: A3#
• 3rd String: D4#
• 2nd String: G3
• 1st String: C4

How to Tune:

This tuning involves significant detuning across all strings. When tuning down 4 semitones or more, it is generally advised to use a heavier gauge string set to maintain proper string tension, intonation, and playability, as standard gauge strings may become too slack and prone to fret buzz. For these extreme drops, a baritone string set is highly recommended.

• 6th String: Tune down 6 semitones to A2#. This is a very significant drop, suggesting a heavier gauge string for optimal performance.
• 5th String: Tune down 4 semitones to F2. A heavier gauge string is recommended.
• 4th String: Tune down 4 semitones to A3#. A heavier gauge string is recommended.
• 3rd String: Tune down 4 semitones to D4#. A heavier gauge string is recommended.
• 2nd String: Tune down 4 semitones to G3. A heavier gauge string is recommended.
• 1st String: Tune down 4 semitones to C4. A heavier gauge string is recommended.