All Fourths

All Fourths

Among alternative tunings for the guitar, all-fourths tuning is a regular tuning. In contrast, the standard tuning has one irregularity—a major third between the third and second strings—while having perfect fourths between the other successive strings. The standard tuning's irregular major-third is replaced by a perfect fourth in all-fourths tuning, which has the open notes

E-A-D-G-C-F.

Among regular tunings, this all-fourths tuning best approximates the standard tuning.

In all guitar tunings, the higher-octave version of a chord can be found by translating a chord by twelve frets higher along the fretboard. In every regular tuning, for example in all-fourths tuning, chords and intervals can be moved also diagonally. For all-fourths tuning, all twelve major chords (in the first or open positions) are generated by two chords, the open F major chord and the D major chord. The regularity of chord-patterns reduces the number of finger positions that need to be memorized. Jazz musician Stanley Jordan plays guitar in all-fourths tuning; he has stated that all-fourths tuning "simplifies the fingerboard, making it logical".

However, seventh chords require severe hand-stretching in not only standard tuning, but also all-fourths tuning. For example, the C7 chord has notes on frets 3-8 in standard tuning (and all-fourths tuning). Consequently, seventh chords are rarely played in standard tuning. In their stead, standard-tuning and all-fourths tuning use "alternatively voiced" chords, which have the same notes but in different order (and perhaps in a different octave). An illustration shows a C7 chord (in standard tuning), which would be extremely difficult to play, and an "alternatively voiced" C7. In comparison, all seventh-chords can be played on three consecutive frets in major-thirds tuning.

Among all regular tunings, all-fourths tuning E-A-D-G-C-F is the best approximation of standard tuning, which is more popular. An advantage of standard tuning is that it has many six-string chords, unlike all-fourths tuning. All-fourths tuning is traditionally used for the bass guitar; it is also used for the bajo sexto.