The tuning you've named "CFCEFC" is a fascinating and sonically rich open tuning, as you described, born from experimentation. It provides a distinct palette for creative expression, blending familiar major tonalities with unique harmonic extensions.

Verbal Analysis:

Upon strumming this tuning open, you'll immediately hear a bright and full C Major tonality. However, it's not a simple C Major triad; the repeated F notes (Perfect 4ths or 11ths) interwoven with the C and E create a unique harmonic landscape. This gives the tuning a characteristic "open C Major with an added 4th" or "Cadd11" feel, lending it a slightly suspended, almost folky or ethereal quality that is both resonant and inviting. It's excellent for creating rich drones, expansive soundscapes, and expressive fingerpicking passages. The way the notes are layered, particularly with the E3 (Major Third) surrounded by C's and F's, creates a lush and harmonically interesting canvas.

Technical Analysis:

The open strings are tuned to C2-F2-C3-E3-F3-C4. Analysing these notes reveals the following intervallic structure from the lowest C:

• Low C (C2): The Root
• F (F2): A Perfect 4th above the root
• C (C3): An Octave above the root
• E (E3): A Major 3rd above the root
• F (F3): A Perfect 4th (or 11th) above the root, or a Perfect 2nd above the E
• High C (C4): Two Octaves above the root

This configuration essentially forms a C Major chord with the added color of the F notes. It's akin to a C Major 11th chord without the G (5th) or Bb (minor 7th) but with a strong emphasis on the 4th/11th. This structure naturally facilitates the creation of C Major and F Major related harmonies. Barring across all strings at various frets will often yield other major chords, making it highly versatile for open chord playing and slide guitar. For instance, barring at the 5th fret would produce an F Major chord, and at the 7th fret, a G Major chord, leveraging the inherent major structure. The tuning's unique stacked fourths (C-F, E-F) and octaves (C-C) provide interesting harmonic possibilities for both melodic and rhythmic playing.

Open String Notes:

String 6 (Low E): C2
String 5 (A): F2
String 4 (D): C3
String 3 (G): E3
String 2 (B): F3
String 1 (High E): C4

How to Tune:

To achieve the "CFCEFC" tuning from standard E Standard tuning (E-A-D-G-B-E), please follow these steps carefully:

• String 6 (Low E to C): Tune down 4 semitones. This is a significant drop, transforming your low E string into a C.
• String 5 (A to F): Tune down 4 semitones. Your A string will become an F.
• String 4 (D to C): Tune down 2 semitones. Your D string will become a C.
• String 3 (G to E): Tune down 3 semitones. Your G string will become an E.
• String 2 (B to F): Tune down 6 semitones. This is a very substantial drop (a tritone or augmented 4th) and significantly alters the string's tension. Your B string will become an F.
• String 1 (High E to C): Tune down 4 semitones. Your high E string will become a C.

Important Note on String Gauges: Please be aware that almost all strings in this tuning require a significant drop in pitch from standard tuning. Specifically, strings 6, 5, 2, and 1 are tuned down 4 or more semitones (string 2 is down 6 semitones). For optimal playability, intonation, and to maintain adequate string tension, it is highly recommended to consider using a heavier gauge string set than standard, especially for the strings with the most significant pitch drops. Tuning down more than 4 semitones can result in very loose strings and potential intonation issues with standard gauges.