The Diatonic Scale for Guitarists

This is the first theory post on Six String Geek, so it's only apt that we start at the very beginning. What better place is there to start than the diatonic scale?

Also known as the major scale, the diatonic scale is arguably the most important scale for a musician to learn. It serves as the foundation for learning to build and break down musical structures from or into their constituent blocks.

Let's begin with a fun little line. Below is a jazzy line played in the C major (or C diatonic) scale. The transcription to this line is at the end of this article.



What is the diatonic scale?

Here are some simple answers:

• The white keys on the piano.
• Do, Re, Me, Fa, So, La, Ti
• The major scale.
  

For the more detailed explanation, , let's first talk about intervals.

What are intervals?

An interval is the distance between two notes. Think about moving around on one string of your guitar. When you move from fret 4 to fret 5, you are moving a "half-step" between the two notes. This interval is sometimes also called a "minor 2nd".

The half-step (or minor 2nd) is the smallest interval. Its distance is 1 fret, e.g, moving from fret 4 to fret 5.

An interval of 2 frets is a whole-step, and is usually called a "major 2nd". So the distance between frets 4 and 6 on a single string on a guitar, is a whole step.

Below is a list of the common interval names, based on their number of half-steps. Also included are a list of common symbols for the interval.

0 - Unison (Technically, this is the smallest interval).
1 - Minor Second (m2, min2), Half-Step
2 - Major Second (2, maj2), Whole-Step
3 - Minor Third (m3, min3)
4 - Major Third (M3, maj3)
5 - Fourth (4)
6 - Diminished (dim, dim5), Flat Fifth (b5)
7 - Perfect Fifth (5)
8 - Augmented, Sharp Fifth, Minor Sixth (m6, min6)
09 - Sixth (6, maj6)
10 - Dominant Seventh (dom7, 7), Flat Seventh (b7)
11 - Major Seventh (maj7, M7)
12 - Octave
13 - Minor Ninth (m9, min9), Flat Ninth (b9)
14 - Ninth (9)
15 - Sharp Ninth (#9)
16 - Flat Eleventh (b11)
17 - Eleventh (11)
18 - Sharp Eleventh (#11)
19 - Flat Thirteenth (b13)
20 - Thirteenth (13)

For the purposes of this article, it is only necessary to know about the minor and major 2nd intervals. The other intervals will be introduced in future articles.

Also, guitarists generally use the half-step / whole-step names when referring to the minor and major 2nd intervals, so to stick to the convention, let's use these names.

So, now that you know what intervals are, we can proceed with learning about the diatonic scale. But wait... there's one more useful melodic structure to learn about before we go on: the chromatic scale.

What is the chromatic scale?

The simple answer: "all the keys on the keyboard".

The less-simple answer: The chromatic scale is composed of notes a half-step away from each other.

So let's say you start at fret 5 on the G-string, which is a C, and move up the fretboard in half-step increments. All the notes that you play till the next C make up the C chromatic scale.

The C chromatic scale consists of the following 12 tones:

C - C#/Db - D - D#/Eb - E - F - F#/Gb - G - G#/Ab - A - A#/Bb - B - C

The interval between the first C and the last C is known as an Octave.

Here is what the chromatic scale looks like in tablature.


Okay, now that you know what the chromatic scale is, let's get to the diatonic scale. For real this time.

So... what is the diatonic scale?

The diatonic scale is the set of notes that follow the interval pattern:

W - W - H - W - W - W - H

Above, W stands for whole-step, and H stands for half step. So the scale consists of two whole-steps followed by a half-step, then three whole-steps followed by a half-step.

So, given this formula, what does the C diatonic scale look like?

C - D - E - F - G - A - B - C

Here it is notated (click to enlarge):



And here is what it sounds like:



Wait, what? How did WWWHWWH turn into CDEFGABC?

Okay, lets start with the key, which is C. The first interval in the formula is W, for whole-step. Looking at the chromatic scale above, the note which is only whole-step away from C is D. There you have your second note.

The next interval is also a whole-step. The note that is a whole-step away from D is E. Then there's the half step. Notice that there is no note between E and F on the chromatic scale? The F note is a half-step above E. If you look at the keys on the piano, you'll see that there's no black key between E and F.

By now, you should understand the process of constructing the diatonic scale for any given key. Try it yourself. See if you can build the diatoinc scales for all keys. Here are the notes of the D diatonic scale:

D - E - F# - G - A - B - C#

Alternate notation for the diatonic scale.

There's another way to express the formula of the diatonic scale, which is by using the interval names. Here's what it looks like:

Unison - maj2 - maj3 - 4 - 5 - 6 - maj7

If you look at the interval table above, and substitute these interval names with the note names based on the number of half-steps for the interval, you'll get the same result.

For example, the first note in the D diatonic scale is D, which is 0 half-steps away (Unison). The second note is E, derived from maj2 (2 half steps away). The third note is F#, derived from maj3 (4 half-steps). And so on.

Expressing scales in this notation is actually easier to do once you're comfortable with the diatonic scale, because other scales are more commonly expressed in relation to the diatonic scale. For example, the jazz melodic-minor scale is the diatonic scale with a flattened 3rd (min3). This simply means, take the diatonic scale and replace the maj3 with the min3, as so:

Unison - maj2 - min3 - 4 - 5 - 6 - maj7

In the key of C, this would be:

C - D - Eb - F - G - A - B

As another example, the harmonic minor scale has a flattened 3rd and 6th, like so:

Unison - maj2 - min3 - 4 - 5 - min6 - maj7

In the key of A, this would be:

A - B - C - D - E - F - G#

So, in conclusion, in addition it to being a frequently-used scale in classical and modern music, the diatonic scale serves as a reference point to building and naming of intervals, chords, and other scales.

If you have another look at the interval names above, you'll see that the flats, sharps, majors, and minors are all relative to their position on the diatoinc scale.

Enough talk. Let's play. Below is the transcription of the lick played in the beginning of this article. Enjoy.



For more information on the diatonic scale, read the excellent Wikipedia article at: http://en.wikipedia.org/wiki/Diatonic_scale.