This is the iconic Iris Tuning, famously used by the Goo Goo Dolls. It's an atmospheric and resonant open tuning designed to simplify playing the distinctive chords and melodies of the song "Iris".

Verbal Analysis

The Iris tuning creates a rich, open D sound, perfect for strumming and fingerstyle playing that evokes a sense of expansive melancholy. The prevalence of D notes across multiple strings (D3, D3, D3, D4, D4) provides a beautiful, drone-like sustain, allowing for easy execution of a full D major chord with a single strum. The most striking feature is the exceptionally low B0 on the 6th string. This B0 provides an incredibly deep, resonant bass foundation, far below standard guitar range, which contributes significantly to the tuning's unique sonic landscape. While the tuning simplifies playing in the key of D, the low B also opens up possibilities for interesting harmonic extensions or pedal tones, giving chords an added depth and complexity.

Technical Analysis

The open tuning notes are as follows: B0-D3-D3-D3-D4-D4.

• Chord Voicing: The open strings form a clear D major chord (D3-D3-D3-D4-D4) over a very low B root. Technically, this could be interpreted as a Dsus2/B or a Bm7(no5), providing a deeply resonant and somewhat ambiguous harmonic foundation.
• Intervals:
  • String 6 (B0) to String 5 (D3): An unusual and vast interval of a minor 17th (minor third plus two octaves), contributing to the wide sonic range. This extremely low B0 is notably below the range of a standard guitar and would typically require a very heavy gauge string or even an extended-range instrument to achieve proper tension and intonation.
  • String 5 (D3) to String 4 (D3): Unison
  • String 4 (D3) to String 3 (D3): Unison
  • String 3 (D3) to String 2 (D4): Octave
  • String 2 (D4) to String 1 (D4): Unison
• Chord Accessibility: This tuning greatly facilitates playing in D major. Open D major, Dsus2, and Dsus4 chords are readily available. By barring across the D3-D3-D3-D4-D4 strings at various frets, you can easily create major chords (e.g., a barre at the 2nd fret yields E major, 5th fret yields G major).
• Drone Quality: The multiple D notes create a powerful, resonant drone effect, which is a hallmark of open tunings and especially effective for sustained chords and melodic lines.

How to Tune

To achieve the Iris Tuning, follow these string adjustments:

• String 6 (Lowest String): Tune to B0. This requires tuning down 2 semitones. (Movement within normal range)
• String 5: Tune to D3. This requires tuning up 5 semitones. (Caution: Tuning up 5 semitones is a significant adjustment; consider a different gauge string to prevent breakage or excessive tension.)
• String 4: Tune to D3. Keep as is; no change (0 semitones). (No change)
• String 3: Tune to D3. This requires tuning down 5 semitones. (Caution: Tuning down 5 semitones is a significant adjustment; string tension may become very loose, potentially affecting playability or intonation. A different gauge string might be advised.)
• String 2: Tune to D4. This requires tuning up 3 semitones. (Movement within normal range)
• String 1 (Highest String): Tune to D4. This requires tuning down 2 semitones. (Movement within normal range)

Remember to always tune carefully, especially when making large pitch adjustments, to protect your instrument and strings.

String 6: B0

String 5: D3

String 4: D3

String 3: D3

String 2: D4

String 1: D4