Verbal Analysis:

The "Em+G7 tuning" is an exceptionally versatile and expressive open tuning, particularly popular among guitarists who delve into blues, rock, and slide styles. As its name elegantly suggests, this tuning artfully combines the harmonic characteristics of an E minor chord with a G dominant 7th, creating a rich and dynamic sonic palette. This blend allows for a seamless transition between a soulful minor feel and a gritty, driving dominant sound, making it a powerful tool for expressive playing.

It is especially well-suited for slide guitar, where the open strings' resonant quality allows for fluid glissandos and expressive vocal-like phrasing. The inherent dominant 7th nature, particularly on the middle strings, means that achieving that classic bluesy tension is often as simple as barring a single fret. The presence of the low E string provides a robust bass foundation, anchoring the minor tonality or adding depth to the dominant harmonies.

This tuning makes several chords readily available. You can easily achieve full open E minor and G7 chords, facilitating quick harmonic shifts. Furthermore, a simple single-finger bar across the top five or all six strings at any given fret will yield movable dominant 7th or minor 7th chord shapes, depending on your harmonic interpretation. This makes it highly efficient for both rhythm accompaniment and intricate lead work.

Technical Analysis:

The open string notes for this tuning are, from low to high: E2 - G2 - D3 - F3 - B3 - D4.

Analysing the harmonic content reveals the core of its versatility:

• The notes E - G - B are prominently featured, forming a clear E minor triad, providing a melancholic or grounded minor tonality.
• The notes G - B - D - F are also present, constructing a strong G dominant 7th chord, which is essential for blues and rock.

When strummed open, the combination of these notes (E-G-D-F-B-D) creates a harmonically rich, somewhat dense sound that can be interpreted as an Em7(add11) or a G13 (with an omitted 9th). The tuning's structure, particularly the G-D-F-B-D on the top five strings, bears a resemblance to an Open G tuning but with a flattened 7th (F) on the 3rd string instead of G, thereby giving it its dominant characteristic. The low E string then contributes the minor third relative to G, or functions as the root for an E minor harmony. The varied intervals between strings offer a full and complex voicing that is highly conducive to both slide playing and creative open chord voicings.

Tuning Notes:

Here are the specific notes for each string, from the thickest (low E) to the thinnest (high E):

• String 6 (Low E): E2
• String 5 (A): G2
• String 4 (D): D3
• String 3 (G): F3
• String 2 (B): B3
• String 1 (High E): D4

How to Tune:

To achieve the 'Em+G7 tuning' from standard E-A-D-G-B-E tuning, please follow these precise instructions:

• String 6 (Low E): Keep as is; no change (0 semitones). The note remains E2.
• String 5 (A): Tune down 2 semitones from its standard A2 to G2.
• String 4 (D): Keep as is; no change (0 semitones). The note remains D3.
• String 3 (G): Tune down 2 semitones from its standard G3 to F3.
• String 2 (B): Keep as is; no change (0 semitones). The note remains B3.
• String 1 (High E): Tune down 2 semitones from its standard E4 to D4.

Important Note on String Tension: Please be mindful when adjusting string tension. Generally, tuning up or down by 3 or 4 semitones from standard pitch might require a different string gauge to maintain optimal tension and prevent potential damage to your instrument or strings. For this 'Em+G7 tuning', all string movements are either no change or a moderate 2 semitones down, which is typically safe and well within the limits for standard string gauges. Always tune carefully and listen for any signs of excessive tension or looseness.