D7sus Tuning Analysis

This tuning, aptly named d7sus, is specifically designed as a "modal blues tuning for lap steel with a dom 7 but no 3rd." It cultivates a distinctive, open sound, making it particularly well-suited for blues, slide guitar, and other genres where a clear, resonant dominant seventh chord quality, unburdened by a major or minor third, is desired. The tuning inherently provides a strong, foundational D dominant seventh chord, with the deliberate omission of the third granting it a versatile modal character.

Technical Breakdown:

The open string notes, from low to high, are configured as D2-A2-D3-A3-C4-D4. An analysis of these notes reveals the following harmonic structure:

• String 6 (D2): The fundamental root note, establishing a deep and resonant foundation for the tuning.
• String 5 (A2): The perfect fifth, providing harmonic stability and reinforcing the root.
• String 4 (D3): An octave of the root, which significantly adds to the tuning's richness and depth.
• String 3 (A3): An octave of the perfect fifth, further broadening the harmonic overtone series and chordal density.
• String 2 (C4): The crucial minor seventh, which definitively establishes the dominant seventh quality of the chord. Its presence is key to the tuning's inherent bluesy feel.
• String 1 (D4): Another octave of the root, completing the chord voicing with a bright, ringing tone.

This arrangement effectively forms a D5 chord (comprising D and A) with an added minor seventh (C). While the tuning's name includes "sus," it's important to note that a traditional suspended fourth (G) or suspended second (E) is not present in the open strings. In this context, "sus" likely refers to the deliberate absence of a defined major or minor third, which imparts an ambiguous, open, and modal character. This allows the tuning to seamlessly adapt to both major and minor blues tonalities, essentially functioning as a D dominant 7th chord without a third (D7no3).

Chords and Playability:

The D7sus tuning is exceptionally player-friendly, especially for slide guitar. With no notes fretted, the open strings already produce a full and resonant D7(no3) chord, offering immediate musicality.

• Effortless Barre Chords: By simply barring across all strings at any fret with a finger or a slide, you instantly create the corresponding dominant seventh (no 3rd) chord. For instance, a barre at the 5th fret yields a G7(no3) chord, and at the 7th fret, an A7(no3) chord. This makes navigating common blues progressions (I-IV-V) incredibly straightforward and intuitive.
• Modal Flexibility: The intentional absence of a third means you retain significant harmonic flexibility. You can easily imply a major or minor tonality by adding just one finger; for example, fretting an F on any D string for a D minor 7 sound, or an F# for a D major 7, without conflicting with an existing third in the open tuning.
• Powerful Drone Capabilities: The multiple D and A strings spanning across different octaves create a rich, powerful, and sustained drone effect, which is highly effective for blues, folk, and various ambient musical styles.
• Full Open Voicings: The wide intervals and octave repetitions among the lower strings (D2 to A2, A2 to D3) provide a lush, full-bodied sound that is excellent for both strumming and arpeggiated patterns.

In summary, this D7sus tuning is an outstanding choice for guitarists seeking a powerful, versatile, and blues-infused open tuning that actively encourages expressive slide playing and deep modal exploration.

Open String Notes:

• String 6 (Low E): D2
• String 5 (A): A2
• String 4 (D): D3
• String 3 (G): A3
• String 2 (B): C4
• String 1 (High E): D4

How to Tune from Standard E-A-D-G-B-E:

To achieve the D7sus tuning, follow these specific instructions for each string. Always use a reliable tuner and make adjustments slowly and carefully. While the string movements for this particular tuning are within generally safe limits, always exercise caution when tuning strings significantly up or down.

• String 6 (Low E): Tune down 2 semitones to D2. (Original E2 moves to D2).
• String 5 (A): Keep as is; no change (0 semitones). It remains A2.
• String 4 (D): Keep as is; no change (0 semitones). It remains D3.
• String 3 (G): Tune up 2 semitones to A3. (Original G3 moves to A3).
• String 2 (B): Tune up 1 semitone to C4. (Original B3 moves to C4).
• String 1 (High E): Tune down 2 semitones to D4. (Original E4 moves to D4).

After making all adjustments, it's a good practice to re-check the tuning of all strings, as changes in tension on one string can sometimes subtly affect the pitch of others.