Verbal Description

The A#FGCGA#F tuning, often notated as BbFGCGBbF, is a unique and highly resonant setup designed for a 7-string guitar. As its description suggests, it is a "4 sympathetic tuning," meaning the open notes C, F, G, and Bb (A#) are common tones across four major keys: Ab, Eb, Bb, and F. This makes the tuning incredibly versatile for playing melodically and harmonically within these specific key centers, allowing for rich, tonal exploration without extensive fretting.

When strummed open, this tuning produces a complex, yet remarkably resonant sound due to the careful arrangement of notes, including octaves of A#/Bb and F. The lowest strings (A#2/Bb2, F2) establish a strong foundational fifth, while the G2, C3, G3, A#4/Bb4, and F4 strings create a dense, ringing harmony. The presence of multiple octaves (A#2 and A#4; F2 and F4; G2 and G3) adds a natural fullness and sustain to the open strings, making the instrument feel very "alive" and rich in overtones.

While not designed for simple major or minor open chords in the traditional sense, the sympathetic nature allows for creative voicings. Due to the inherent resonance and common tones, a simple barre across all strings at any fret will likely yield rich, extended harmonies or modal voicings that maintain the tuning's unique sympathetic qualities. For example, a barre at the first fret would yield B, F#, G#, C#, G#, B, F#, a complex chord ripe for modern composition. The emphasis here is on the tonal quality and resonance within the specified keys, making it excellent for atmospheric soundscapes, fingerstyle playing that exploits open string drones, and improvisation that leans into the inherent harmonic possibilities.

Technical Analysis

This is a 7-string guitar tuning with the following open notes from lowest to highest string: A#2, F2, G2, C3, G3, A#4, F4. The interval structure, relative to the lowest A#2 (Bb2), is as follows:

• String 7 (A#2): Root (Bb2)
• String 6 (F2): Perfect 5th (7 semitones) above A#2/Bb2
• String 5 (G2): Major 6th (9 semitones) above A#2/Bb2
• String 4 (C3): Major 9th (14 semitones) above A#2/Bb2, or an octave and a major 2nd
• String 3 (G3): Major 13th (21 semitones) above A#2/Bb2, or two octaves and a major 6th
• String 2 (A#4): Octave (24 semitones) above A#2/Bb2
• String 1 (F4): Perfect 5th (7 semitones) above A#4, or two octaves and a perfect 5th (31 semitones) above A#2/Bb2

The tuning features a strong fundamental with the A#2 and F2 (Bb and F) forming a perfect fifth. The subsequent strings introduce G2, C3, and G3, which are key common tones across the identified sympathetic keys (Ab, Eb, Bb, F). The higher A#4 and F4 reinforce the tonic and dominant, creating a rich harmonic overtone series. The presence of multiple octaves (A#2-A#4, F2-F4, G2-G3) ensures a full, thick sound across the instrument's range. This non-standard intervalic relationship is clearly optimized for sympathetic resonance and modal playing within the specified tonal centers rather than for traditional major/minor chord shapes.

Open String Notes (from lowest to highest)

String 7 (Lowest): A2#
String 6: F2
String 5: G2
String 4: C3
String 3: G3
String 2: A4#
String 1 (Highest): F4

How to Tune

To achieve the A#FGCGA#F tuning on your 7-string guitar, follow these specific string adjustments. The instructions below describe the movement needed for each string to reach its target open note:

• String 7 (A2#): Tune down 1 semitone.
• String 6 (F2): Tune up 1 semitone.
• String 5 (G2): Tune down 2 semitones.
• String 4 (C3): Tune down 2 semitones.
• String 3 (G3): Keep as is; no change.
• String 2 (A4#): Tune down 1 semitone.
• String 1 (F4): Tune up 1 semitone.

Important Tuning Note: This tuning involves relatively small adjustments, with no string movements exceeding 2 semitones up or down. Generally, for changes exceeding 4 semitones in either direction, considering a different string gauge is advisable to ensure optimal string tension and prevent damage. This tuning falls well within safe limits for standard string gauges.