Diatonic Double Stops - Blitzstar Guitar

A double stop — also called a harmonic interval or a diad — is defined as two notes played at the same time.

A double stop can be incorporated into a solo, used as a rhythm fill or to harmonize a melody.

Double stops sound best if they are diatonic, both notes belonging to the same harmonized major scale. Any harmonic interval can be a double stop but thirds, sixths and fourths sound best and are the most commonly played.

This post will cover how to construct diatonic double stops — thirds, sixths and fourths.

It will also provide common fingerings for each double stop, along with instruction on how to play them on a guitar in any key.

Diatonic Thirds

To identify the diatonic thirds in any given major scale, we need to harmonize the scale in intervals of a third.

Harmonize a C Major Scale in Thirds

To harmonize a scale in thirds we take each degree of the scale and add the note an interval of a third above it, using only notes from the scale.

Fig.1 shows a C major scale and a C major scale harmonized in thirds.

Fig.1

Diatonic Thirds: Theory

We know from a previous post that in a major scale, diatonic thirds will be major or minor in quality.

The intervals built on the first, fourth and fifth degrees of the scale will be major thirds:

C to E.
F to A.
G to B.

The intervals based on the second, third, sixth and seventh degrees of the scale will be minor thirds:

D to F.
E to G.
A to C.
B to D.

Fig.2 shows the major and minor third intervals in a C major scale.

Fig.2

Diatonic Thirds: On a Guitar

Fig.3 shows the interval shapes for major and minor thirds.

Fig.3

You can use the interval shapes to play the diatonic thirds in any major key, based on any major scale.

The diatonic thirds in C major are shown in fig.4. The major third intervals are in blue; the minor third intervals in green.

Fig.4

Diatonic Fourths

To identify the diatonic fourths in any given major scale, we need to harmonize the scale in intervals of a fourth.

Harmonize a C Major Scale in Fourths

To harmonize a scale in fourths we take each degree of the scale and add the note an interval of a fourth above it, using only notes from the scale.

Fig.5 shows a C major scale harmonized in fourths.

Fig.5

Diatonic Fourths: Theory

We know from a previous post that in a major scale, the diatonic fourth intervals are perfect fourths except for the interval built on the fourth scale degree, which is an augmented fourth (F to B in a C major scale).

Fig.6 shows the perfect and augmented fourth intervals in a C major scale.

Fig.6

Diatonic Fourths: On a Guitar

Fig.7 shows the interval shapes for perfect and augmented fourths.

Fig.7

You can use the interval shapes in to play the diatonic fourths in any major key, based on any major scale.

Fig.8 shows the diatonic fourths in C major. The perfect fourth intervals are in blue; the augmented fourth interval is in green.

Fig.8

Diatonic Sixths

To identify the diatonic sixths in any given major scale, we need to harmonize the scale in intervals of a sixth.

Harmonize a C Major Scale in Sixths

To harmonize a scale in sixths we take each degree of the scale and add the note an interval of a sixth above it, using only notes from the scale.

Fig.9 shows a C major scale harmonized in sixths.

Fig.9

Diatonic Sixths: Theory

We know from a previous post that in a major scale, diatonic sixths will be major or minor in quality.

The intervals built on the first, second, fourth and fifth degrees of the scale will be major sixths:

C to A.
D to B.
F to D.
G to E.

The intervals based on the third, sixth and seventh degrees of the scale will be minor sixths:

E to C.
A to F.
B to G.

Fig.10 shows the major and minor sixth intervals in a C major scale.

Fig.10

Diatonic Sixths: On a Guitar

Fig.11 shows the interval shapes for major and minor sixths.

Fig.11

You can use the interval shapes to play the diatonic sixths in any major key, based on any major scale.

Fig.12 shows the diatonic sixths in C major.

The major sixth intervals are in blue; the minor sixth intervals in green.

Fig.12

Interval Shapes

Because we can play the same note in multiple places on a guitar, there are multiple shapes for each interval.

The two notes contained in an interval can be on adjacent strings or there can be a string (or more) between them. The interval shapes that include notes on two adjacent strings are the same for string sets:

One and two.
Three and four.
Four and five.
Five and six.

Because of the way a guitar is tuned, the interval shapes are different when played on strings two and three.

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