The "C7 sus2" tuning is a distinctive and powerful setup for a 7-string guitar, or a 6-string with an extended low range, offering a rich sonic palette. It's built around a C dominant 7th suspended 2nd chord, making it ideal for blues, jazz-fusion, rock, and experimental genres where a full, resonant, and slightly ambiguous dominant sound is desired.

Verbal Analysis

Imagine a deep, resonant C acting as your anchor, surrounded by the strong, open sound of G and D. This tuning immediately evokes a sense of both stability and a yearning, thanks to the suspended 2nd (D) and the flat 7th (A#/Bb). It has a bluesy, open quality, allowing for ringing arpeggios and big, expansive chords. The low C provides incredible depth, while the repeated G and D notes across the strings create a natural resonance, making it feel very "open" and playable. It’s a tuning that invites exploration, where strumming all open strings yields a complex, yet pleasing, C7sus2 chord.

Technical Analysis

The tuning consists of the notes C2-G2-C3-D3-G3-A#4-D4. Analyzing the intervals from the lowest C (C2):

• String 7 (C2): Root (P1)
• String 6 (G2): Perfect Fifth (P5)
• String 5 (C3): Octave (P8) - reinforcing the root
• String 4 (D3): Major Second (M2) - the 'sus2' element
• String 3 (G3): Octave of the Fifth (P8 of P5) - reinforcing the G
• String 2 (A#4): Minor Seventh (m7) - providing the dominant '7' quality (A# is enharmonically Bb)
• String 1 (D4): Octave of the Major Second (P8 of M2) - reinforcing the 'sus2' and adding brightness

This arrangement precisely outlines a C7sus2 chord (C-D-G-Bb), with significant emphasis on the root (C), fifth (G), and suspended second (D). The duplicated notes across different octaves create a thick, full sound.

Open Chords and Playability

Strumming all open strings produces a rich C7sus2 chord. Due to the consistent intervals, simply barring across any fret will yield a new dominant suspended 2nd chord (e.g., barre at the 3rd fret for Eb7sus2, or at the 5th fret for F7sus2).

• C7sus2 Voicings: The open strings provide a powerful voicing. Experiment with lifting fingers to find inversions or extensions.
• Gsus2/Gsus4: The G2-C3-D3-G3 (strings 6-5-4-3) can easily imply Gsus2 or Gsus4 with slight fingerings.
• Drop Tunings: The low C offers a powerful foundation for heavy riffs, making it excellent for genres that utilize extended range or drop tunings.
• Modal Play: The presence of the minor 7th (A#/Bb) makes this tuning very suitable for C Mixolydian or C Dorian applications, opening up expressive blues and jazz lines.

Tuning Notes

• String 7: C2 (Low C)
• String 6: G2
• String 5: C3
• String 4: D3
• String 3: G3
• String 2: A#4 (A sharp / B flat)
• String 1: D4 (High D)

How to Tune to C7 sus2

To achieve the "C7 sus2" tuning from standard 7-string tuning (B-E-A-D-G-B-E), follow these string adjustments. Remember to always tune carefully and gradually. Generally, for movements exceeding 4 semitones up or down, considering a different string gauge is advisable to prevent string breakage or intonation issues, though this particular tuning remains within safe limits.

• String 7 (Lowest String - typically B): Tune up 1 semitone to C2.
• String 6 (typically E): Tune up 3 semitones to G2.
• String 5 (typically A): Tune up 3 semitones to C3.
• String 4 (typically D): Keep as is; no change (0 semitones) at D3.
• String 3 (typically G): Keep as is; no change (0 semitones) at G3.
• String 2 (typically B): Tune down 1 semitone to A#4.
• String 1 (Highest String - typically E): Tune down 2 semitones to D4.