The Cmadd9 tuning presents a rich, melancholic, and deeply resonant soundscape, particularly well-suited for a 5-string acoustic guitar where the highest E string has been removed or is not utilized, as indicated by its description as being "Made for a cheap acoustic with no high e string".

Technical Analysis

The open strings are tuned to C2, D3#, D4#, D4, and G3. Analyzing these notes reveals the following intervals relative to the root C:

• String 5 (C2): Root (C)
• String 4 (D3# / Eb3): Minor Third (Eb)
• String 3 (D4# / Eb4): Minor Third (Eb) - an octave higher than String 4
• String 2 (D4): Major Second / Ninth (D)
• String 1 (G3): Perfect Fifth (G)

This unique combination forms a Cm(add9) chord (C - D - Eb - G) spread across the open strings, with the Eb duplicated an octave higher. The absence of a traditional major third creates an immediate minor tonality. The 'add9' (D) adds a sophisticated, jazzy, or contemporary feel, preventing the minor chord from sounding overly simplistic.

Verbal Analysis & Playability

This tuning has a dark, introspective character, perfect for atmospheric pieces, blues, or fingerstyle arrangements that lean towards a minor key. The open strings themselves form a beautiful Cm(add9) chord, meaning strumming all open strings will yield a full, harmonically rich sound without any fretting.

Due to the open Cm(add9), many common chord shapes will be re-voiced or rendered differently. Barre chords will likely be simplified, as the minor third and ninth are already present. Players can experiment with moving simple shapes up the neck, effectively creating variations of Cm(add9) in different inversions, or other chords that complement C minor. For example, a G minor or G major chord could be easily voiced by using the G3 on String 1 and finding a B (or Bb) and D on other strings. The lower C2 provides a deep, foundational bass note, giving the tuning a powerful presence.

The close proximity of D4# (Eb4) and D4 (D) on adjacent strings (String 3 and String 2) is interesting; these notes are only a semitone apart, offering opportunities for dissonant or close harmony voicings.

Open String Notes:

• String 5 (Lowest): C2
• String 4: D3#
• String 3: D4#
• String 2: D4
• String 1 (Highest): G3

How to Tune:

(Assumes starting from standard guitar tuning: E-A-D-G-B for the 5 strings)

• String 5 (Low E String, from E2): Tune down 4 semitones. (Note: A downward change of 4 semitones is significant; consider a heavier gauge string for optimal tension.)
• String 4 (A String, from A2): Tune down 6 semitones. (Warning: A downward change of 6 semitones is substantial. For best playability and to avoid string floppiness, a heavier gauge string is strongly advised.)
• String 3 (D String, from D3): Tune up 1 semitone.
• String 2 (G String, from G3): Tune up 7 semitones. (Warning: An upward change of 7 semitones is very significant and may put excessive stress on standard gauge strings, risking breakage. A lighter gauge string or caution is highly recommended.)
• String 1 (B String, from B3): Tune down 9 semitones. (Warning: A downward change of 9 semitones is extreme. It is highly recommended to use a significantly heavier gauge string to maintain adequate tension and playability.)

Always tune slowly and check string tension carefully, especially with large semitone adjustments.