The '4 String Open E7' tuning, as its name suggests, is a unique and resonant four-string guitar setup that immediately presents an E7 chord when played open. This tuning is perfect for blues, rock, and slide guitar, offering a strong harmonic foundation in the key of E. Its creator aimed for versatility, and indeed, this tuning provides an excellent canvas for exploring various musical styles with a simplified string set.

Technical Analysis

• Open Notes: The tuning comprises the notes E2, B2, D3, and G4#. These notes collectively form a clear E7 (E dominant seventh) chord.
• Chord Structure:
  • String 4 (E2): Root (E)
  • String 3 (B2): Perfect 5th (B)
  • String 2 (D3): Minor 7th (D)
  • String 1 (G4#): Major 3rd (G#)
• Intervals: The intervals are consistent with an E7 chord, providing a rich, bluesy sound right out of the gate. The high G4# on the first string adds a bright, cutting quality to the overall voicing, which can be particularly effective for lead lines or vibrant chord extensions.

Chords and Playability

With an E7 chord as the open voicing, this tuning is highly intuitive for playing in the key of E. Barring across all four strings at any fret will instantly produce a dominant 7th chord (e.g., barre at fret 1 gives F7, fret 2 gives F#7). This makes transposing dominant 7th chords very straightforward across the fretboard.

The consistent intervals (Root, 5th, 7th, 3rd) make it easy to find other chord voicings and melodic possibilities:

• Slide Guitar: This tuning is exceptionally well-suited for slide guitar due to its open chord structure. Moving a slide across the strings will always produce a dominant 7th chord, allowing for easy melodic and harmonic improvisation.
• Blues and Rock: The E7 voicing is fundamental to blues and rock music, making this tuning a natural fit for these genres. Simple chord progressions and riffs will sound full and authentic.
• Simplified Chording: For players focusing on four-string arrangements, this tuning offers a powerful and musically useful open chord. By using a single finger to fret across all strings, a wide range of dominant 7th chords are instantly accessible.
• Related Chords: While the open tuning is E7, closely related chords like E major (by muting or altering the D string) or even A7 (by fretting certain strings) are within easy reach with minimal finger movement due to the foundational E and B notes.

How to Tune

To achieve the '4 String Open E7' tuning, follow these specific string movements from your guitar's current setup. It is generally recommended to use a reliable electronic tuner for accuracy.

• String 4 (Lowest): Tune to E2. Keep as is; no change (0 semitones).
• String 3: Tune to B2. This requires tuning up 2 semitones.
• String 2: Tune to D3. Keep as is; no change (0 semitones).
• String 1 (Highest): Tune to G4#. This requires tuning up 1 semitone.

Note on String Gauges: For significant tuning changes (generally exceeding 4 semitones up or down from standard pitch), it is often advisable to consider a different string gauge to ensure optimal tension and prevent string breakage or damage to the instrument. In this tuning, String 3 is tuned up 2 semitones and String 1 is tuned up 1 semitone. Both of these movements are well within a safe range for standard string gauges.