Tuesday, September 29, 2009

Pentatonic Axis Positions

Pentatonic scales on the guitar are often thought of primarily as the basis of blues solo styles, usually in the minor mode, usually A minor;


In fact, this pattern is both A minor and C major. This is only one of many pentatonic patterns. This particular pattern is by far the most widely used because of its technical simplicity. There is a note on each string at the 5th fret, each played with the 1st finger. There are no notes played with the second finger and there are three notes played with the 3rd finger (3rd, 4th and 5th strings), and three with the 4th finger (1st, second and 6th strings).

Before examining all the other pentatonic patterns, let's examine the actual tonal structure of the pentatonic scale.

The scale in the tablature above has the following tones;

A - C - D - E - G

The scale degrees of these five tones are;

VI - I - II - III - V

The interval pattern is;

A [minor 3rd] C [whole-step] D [whole-step] E [minor 3rd] G

Of course, we can add the octave of the first tone of the scale at the end;

A [minor 3rd] C [whole-step] D [whole-step] E [minor 3rd] G [whole-step] A

All five of these tones are found at the 5th fret. String by string;

1) A
2) E
3) C
4) G
5) D
6) A

Because the interval relationships are the same at all fret positions on the guitar, if the axis of tones on the 5th fret belong to a pentatonic scale, then so do those at the the other axis positions; the open strings, 10th fret, 12th fret, 17th fret.

Remember, the intervals between the strings are;

[perfect 4th]
[major 3rd]
[perfect 4th]
[perfect 4th]
[perfect 4th]

The three axes are shown in the diagram at the top of this entry at the open strings, 5th fret and 10th fret along with a look at the scale intervals for each, and notation. Also, the rest of the tones are shown as white circles, with gray ovals emphasizing the half-step clusters to bring out the overall diatonic symmetry.

So there are actually three pentatonic scales within each key. The major tonic of each scale is on the 3rd string of that axis, and the minor tonic is on the 6th string.


All contents of this blog are © Mark Newstetter

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