This is a formidable 9-string guitar tuning, specifically known as the "OBESITY nine string tuning for most of their catalogue." It offers a uniquely deep and expansive sonic palette, ideal for heavy genres that demand extreme low-end presence and dense chord voicings.

Technical Analysis

This tuning leverages a standard EADGBE configuration for its top six strings (String 6 to String 1: E2-A2-D3-G3-B3-E4), providing familiarity and accessibility for players accustomed to a 6-string setup. The true character of this tuning emerges from its three lowest strings: C1, E1, and A1. These provide a massive extension into the sub-bass range.

The open strings lay out as follows, from lowest to highest: C1 - E1 - A1 - E2 - A2 - D3 - G3 - B3 - E4. When examined across all nine strings, this tuning does not form a simple, immediately identifiable common open chord in its entirety. However, its structure offers powerful harmonic possibilities:

• The lowest three strings (C1, E1, A1) are particularly interesting. Played together, they outline an A minor chord (A-C-E) or a C major chord with an added 6th (C-E-A). This allows for very resonant and thick low voicings, perfect for chugging riffs and ominous pads.
• The term "Drop C/E/A" aptly describes the significantly lowered pitch of the lowest strings. The C1 note, being the lowest, provides an incredibly deep foundation, common in modern progressive and extreme metal, allowing for profoundly heavy single-note riffs.
• Power chords are easily accessible on the lower strings, especially on the 9th (C1) and 7th (A1) strings. For example, simply fretting the 9th string and playing it alongside the open 8th and 7th (E1, A1) creates a huge, resonant interval. The consistent intervals between the 6th, 5th, and 4th strings (E2, A2, D3 - all perfect 4ths) and the 3rd and 2nd strings (G3, B3 - a major 3rd) facilitate standard chord shapes and scales on the higher register, while the lower strings can be exploited for crushing, extended-range riffs.

How to Tune

To achieve this specific 9-string tuning, follow these precise adjustments to reach the target notes:

• String 9 (C1): Tune down 1 semitone.
• String 8 (E1): Tune down 2 semitones.
• String 7 (A1): Tune down 2 semitones.
• String 6 (E2): Keep as is; no change (0 semitones).
• String 5 (A2): Keep as is; no change (0 semitones).
• String 4 (D3): Keep as is; no change (0 semitones).
• String 3 (G3): Keep as is; no change (0 semitones).
• String 2 (B3): Keep as is; no change (0 semitones).
• String 1 (E4): Keep as is; no change (0 semitones).

All specified string movements are relatively minor and within a safe range, so a different gauge string is not explicitly required based on these changes alone. However, for optimal tone, tension, and clarity when playing such low notes on a 9-string guitar, using a specialized, heavier gauge string set is generally recommended.

String 9: C1 (Lowest string)

String 8: E1

String 7: A1

String 6: E2

String 5: A2

String 4: D3

String 3: G3

String 2: B3

String 1: E4 (Highest string)