This unique 7-string tuning, officially named "Open B add 4", offers a rich and expansive soundscape, particularly for those exploring drone-based compositions or seeking a powerful open chord voicing. It establishes a strong B Major tonality as its foundation, enhanced by the prominent F# (perfect fifth) and an E (perfect fourth/eleventh), giving it a full, resonant quality.

Verbal Analysis

The most striking feature of this tuning is its reentrant nature on the 7th string. Instead of being the lowest note, the 7th string is tuned to F#3, which is actually higher in pitch than the 6th, 5th, and 4th strings. This creates an intriguing open drone for the V (F#) chord, adding depth and harmonic tension without clashing with the IV (E) chord. It allows for a sustained, ringing quality, making it excellent for ambient textures, blues, and heavy, resonant riffs. The overall feel is weighty and powerful, with clear major voicings available across the fretboard. The open Badd4 chord itself is very full, providing a strong harmonic bedrock for exploration.

Technical Analysis

The open strings for this 7-string guitar are:
String 7: F#3 (Reentrant)
String 6: B1
String 5: E2
String 4: B2
String 3: F#4
String 2: B3
String 1: D#5

When played open, these notes collectively form a B major chord with an added 4th (E) and additional F# (5th) and B (root) octaves, essentially a Bmaj11 (without the major 7th). The intervallic structure from lowest B (String 6) is B-E-B-F#-B-F#-D#. This provides a powerful open Badd4 chord. The arrangement facilitates easy access to various voicings:

• Open B Major: By simply muting String 5 (E2), you can achieve a very full B Major chord (B1-B2-F#3-F#4-B3-D#5), offering multiple octaves of the root and fifth, and the crucial major third.
• Open Bsus4/B11: The presence of E2 (the perfect 4th or 11th) on String 5 inherently gives the tuning a suspended quality, or an 11th chord, which is very common in modern and ambient styles.
• V Chord Drone (F#): The reentrant F#3 on String 7 acts as a constant drone, particularly effective when playing over B major or F# major harmonies, adding a deep, sustaining resonance.

Due to the consistent B, F#, and D# notes across the higher strings (String 4 to 1: B2-F#4-B3-D#5), barre chords will easily yield different inversions or extensions of major chords built upon B. Shifting finger shapes can also lead to readily accessible E Major (IV chord) and F# Major (V chord) voicings, as the open strings already provide many of the necessary root and fifth tones. The overall architecture is designed for powerful, ringing chords and melodic lines that can leverage the open string drones.

Here are the notes for each string in this 7-string guitar tuning:

• String 7 (Lowest): F#3
• String 6: B1
• String 5: E2
• String 4: B2
• String 3: F#4
• String 2: B3
• String 1 (Highest): D#5

How to Tune

To achieve the Open B add 4 tuning on a 7-string guitar (assuming a standard B-E-A-D-G-B-E tuning as a reference), follow these instructions for each string:

• String 7 (Lowest B to F#3): Tune up 7 semitones. This is a significant upward adjustment. Consider using a heavier gauge string to prevent breakage and ensure optimal tone.
• String 6 (E to B1): Tune down 5 semitones. This is a substantial drop in pitch. A lighter gauge string might be advisable for better playability and intonation at this lower tension.
• String 5 (A to E2): Tune down 5 semitones. Another significant downward adjustment. A lighter gauge string is recommended here as well.
• String 4 (D to B2): Tune down 3 semitones. This is a noticeable change; tune carefully to ensure stability.
• String 3 (G to F#4): Tune down 1 semitone. This is a minor adjustment.
• String 2 (B to B3): Keep as is; no change (0 semitones). This string retains its standard tuning.
• String 1 (Highest E to D#5): Tune down 1 semitone. This is a minor adjustment.

Important Note on String Gauges: For changes exceeding 4 semitones (either up or down), such as on String 7 (+7 semitones) and Strings 6 & 5 (-5 semitones), it is strongly advised to consider using a different gauge string set specifically designed for such tensions. This will help maintain proper string tension, intonation, playability, and prevent potential damage to your guitar or strings.