The "e7sus" tuning, as suggested by its name, presents an open E7sus4 voicing, making it a highly versatile and resonant choice for blues, slide guitar, and open-chord playing. This tuning is particularly renowned for its suitability on lap steel, where its inherent ambiguity and open character truly shine. The absence of a major or minor third in the open string configuration (E-B-D-E-B-E) means the tuning doesn't commit to either a major or minor tonality, allowing it to function as a powerful dominant 7 chord that can lean either way depending on the melodic context.

Technical Analysis

The open strings are tuned to E2-B2-D3-E3-B3-E4, from the lowest to the highest string. This configuration spells out the notes of an E7sus4 chord (E, B, D, with the E acting as the root and an octave, and B as the 5th). Specifically, the intervals from the root E are: Root (E), Perfect 5th (B), Minor 7th (D), Octave (E), Perfect 5th (B), and Octave (E). This rich voicing provides a full, harmonically ambiguous foundation. The repeated E and B notes across octaves create a strong, resonant drone.

Chords are readily accessible across the fretboard. By simply barring any fret, you can achieve a corresponding 7sus4 chord. For example, barring the 1st fret yields an F7sus4 chord, the 2nd fret an F#7sus4, and so on. This makes it exceptionally intuitive for slide guitarists to navigate and create fluid chord changes and melodic phrases. The open, ringing quality lends itself well to blues progressions, allowing for soulful bends and expressive glissandos.

How to Tune

To achieve the e7sus tuning from standard EADGBe, follow these precise string adjustments:

• Low E String (6th String): Tune to E2. Keep as is; no change (0 semitones).
• A String (5th String): Tune to B2. This requires tuning up 2 semitones from its standard A2.
• D String (4th String): Tune to D3. Keep as is; no change (0 semitones).
• G String (3rd String): Tune to E3. This requires tuning down 3 semitones from its standard G3.
• B String (2nd String): Tune to B3. Keep as is; no change (0 semitones).
• High E String (1st String): Tune to E4. Keep as is; no change (0 semitones).

The string adjustments for this tuning are moderate, with the largest movements being tuning the 5th string up 2 semitones and the 3rd string down 3 semitones. These changes are generally well within the safe limits for standard guitar strings, though as with any tuning alteration, care should always be taken.

String 6 (Low E): Tuned to E2. This is the lowest E on a standard 6-string guitar.

String 5 (A String): Tuned to B2. This note forms a perfect fifth with the low E and is essential for the open chord.

String 4 (D String): Tuned to D3. This note provides the crucial minor seventh interval, giving the tuning its dominant 7th character.

String 3 (G String): Tuned to E3. An octave higher than the low E string, reinforcing the root.

String 2 (B String): Tuned to B3. Another perfect fifth, an octave higher than the 5th string, adding brightness and resonance.

String 1 (High E): Tuned to E4. The highest E note, an octave above the 3rd string, completing the full, ringing E chord.