This is a distinctive 7-string "Open C" tuning, as indicated by its original description, primarily designed for lap steel guitar. The "Open C" designation means that when strummed open, the strings produce a C Major chord, which is fantastic for slide playing. It offers a rich, full, and resonant sound without needing to fret individual notes, making it highly intuitive for creating harmonious backdrops and melodic lines.

Verbal Analysis

The tuning's name, "Open C reentrant," hints at both its primary chordal structure and a non-linear string pitch arrangement. While the term "reentrant" often suggests that string pitches do not strictly ascend or descend from lowest to highest gauge, in this specific manifestation, the notes are presented in a generally ascending pitch order from the lowest numbered string (String 7) to the highest (String 1). However, its wide intervallic spread and the specific voicing provide a unique character. This tuning facilitates extremely fluid playing for major chords and offers a deeply resonant canvas, ideal for the sustained, expressive tones of the lap steel.

Technical Analysis

The open strings are tuned to E2, C2, G2, C3, G3, C4, E4 (from String 7 to String 1). This arrangement perfectly forms a C major chord (C-E-G) across several octaves, providing a very full and harmonious sound. The full complement of notes includes:

• String 7: E2 (Major Third)
• String 6: C2 (Root)
• String 5: G2 (Perfect Fifth)
• String 4: C3 (Root, octave higher)
• String 3: G3 (Perfect Fifth, octave higher)
• String 2: C4 (Root, two octaves higher)
• String 1: E4 (Major Third, two octaves higher)

The tuning robustly reinforces the C major tonality, with three roots (C), two major thirds (E), and two perfect fifths (G) spread across a two-octave range from E2 to E4. This wide span allows for rich voicings and substantial harmonic depth, characteristic of many lap steel tunings.

Open Chords and Reachable Shapes

The most immediate benefit of this tuning is the pristine C major chord produced by simply strumming all open strings. This creates an instant, full, and resonant tonic chord.

• Major Chords: By placing a slide or bar straight across all strings at any given fret, you will automatically produce a major chord. For instance, moving up two frets will yield a D major chord, three frets an Eb major, and so on. This makes playing in major keys incredibly intuitive and allows for smooth, sweeping chord changes.
• Minor Chords and Dominant 7ths: Achieving minor, dominant 7th, or other extended chords typically requires more nuanced slide techniques. This might involve 'slanting' the slide to selectively fret certain strings at different positions or employing specific picking patterns that exclude or include particular notes. For example, to achieve a C minor, the E notes on String 7 and String 1 would need to be flatted to Eb, which would demand precise slide placement.
• Broad Harmonic Textures: The expansive range from E2 to E4 lends itself well to creating broad, sustained harmonic textures, making it highly versatile for various musical styles, from country and blues to ambient and experimental genres.

Target Tuning Notes

String 1: E4

String 2: C4

String 3: G3

String 4: C3

String 5: G2

String 6: C2

String 7: E2

How to Tune

To achieve the Open C Reentrant tuning from a standard 7-string tuning (typically B-E-A-D-G-B-E, from low B to high E), follow these steps for each string:

• String 1 (High E): Keep as is; no change (0 semitones).
• String 2 (B): Tune up 1 semitone to C4.
• String 3 (G): Keep as is; no change (0 semitones).
• String 4 (D): Tune down 2 semitones to C3.
• String 5 (A): Tune down 2 semitones to G2.
• String 6 (Low E): Tune down 4 semitones to C2.
• String 7 (Low B): Tune up 5 semitones to E2. Important Note: Tuning up 5 semitones is a significant change in pitch. While possible, for optimal string tension, playability, and to reduce the risk of string breakage, it is often advisable to consider a heavier gauge string for String 7 when making such a substantial upward adjustment.