This 7-string guitar tuning, aptly named "7 string A# major fourths," is a formidable setup designed for deep, resonant tones and heavy sonic landscapes. As described, it takes a "6 string D# all major fourths" concept and expands it to a 7-string instrument, resulting in an exceptionally low and powerful tuning. It is particularly well-suited for genres like modern metal, djent, and progressive rock, where a massive, articulate low end is crucial for defining the musical texture. The strategic combination of consistently-intervalled lower strings and familiar higher strings provides a versatile platform for both crushing riffs and expressive lead work.

Technical Analysis

The open notes for this tuning, from the lowest (7th) string to the highest (1st) string, are A#2, D#3, G#3, C#4, F#4, B3, E4.

• Interval Structure: The core of this tuning, encompassing the lowest five strings (7th to 3rd: A#2, D#3, G#3, C#4, F#4), is characterized by Perfect Fourths (each interval spanning 5 semitones). This creates a highly logical and symmetrical fretboard layout for these strings, simplifying the memorization of scale patterns and the application of consistent chord shapes.
• Hybrid Design: A notable deviation from a pure 'all fourths' system occurs between the 3rd string (F#4) and the 2nd string (B3), which forms a Perfect Fifth interval *down* (7 semitones). Despite this, the top two strings (2nd to 1st: B3, E4) maintain the familiar Perfect Fourth interval found in standard guitar tuning's high B and E strings. This hybrid structure is a deliberate choice, blending the advantages of a consistent low end with the familiarity of standard higher register playability.
• Playability and Chords:
  • The consistent Perfect Fourths on the lower five strings (A#2, D#3, G#3, C#4, F#4) significantly simplify power chord voicings and complex riffing. Shapes can be easily translated across these strings, promoting fluidity in heavy rhythm playing.
  • The open strings themselves (A#2, D#3, G#3, C#4, F#4, B3, E4) form a rich and complex harmonic landscape. They contain the notes A#, B, C#, D#, E, F#, G#, which collectively outline an A# Phrygian scale. This lends itself to deep, dark, or exotic open-string sonorities and allows for unique suspended or extended chord voicings.
  • By retaining the standard Perfect Fourth interval between the B3 and E4 strings, the tuning ensures that many familiar lead patterns, arpeggios, and higher-register chord shapes from standard guitar tuning remain immediately accessible. This provides a balanced approach, marrying the extended low range with traditional guitar melodicism.
  • While traditional open major/minor chords might be challenging to form across all strings, the tuning is exceptionally conducive to powerful two- and three-note chord voicings, suspended chords, and modal harmonies that effectively leverage its distinct interval structure.

How to Tune to 7 String A# Major Fourths

This tuning is based on a standard 7-string B Standard (B2 E3 A3 D4 G4 B3 E4) tuning. Carefully adjust each string as follows:

• 7th String (Low A# - A2#): Tune down 1 semitones from B2.
• 6th String (D# - D3#): Tune down 1 semitones from E3.
• 5th String (G# - G3#): Tune down 1 semitones from A3.
• 4th String (C# - C4#): Tune down 1 semitones from D4.
• 3rd String (F# - F4#): Tune down 1 semitones from G4.
• 2nd String (B - B3): Keep as is; no change (0 semitones).
• 1st String (High E - E4): Keep as is; no change (0 semitones).

7th String (Low A#): A2#

6th String (D#): D3#

5th String (G#): G3#

4th String (C#): C4#

3rd String (F#): F4#

2nd String (B): B3

1st String (High E): E4