Guitar Scale Theory Explained

You could be a pro guitar player, who can play a lot of seriously technical
and fast lead segments that are rooted in some kind of scale. However, you
may not be familiar with the concepts behind the notes and patterns you

If you are the kind of person who likes to understand how things work,
learning about guitar scale theory will let you understand why those strings
sound the way they do. It will help you give deeper meaning to the fretboard

A guitar scale is defined as any sequence of musical noted ordered by
frequency or pitch. In simpler terms, it is an ascending or descending
sequence of notes.

Further, scales are ordered by pitch.

Pitch is a perceptual attribute that allows the ordering of sounds on a
frequency-related scale extending from low to high.

Now, the question is how do we apply this to the fretboard.

Basic Intervals

In music, each individual note (pitch) on the scale is indicated by one of the
first seven letters of the alphabet A B C D E F G. Moving between these
notes introduces you to the concept of changing pitch, which can be
measured in half and whole steps.

Half Steps (Minor second intervals): If you start with your first finger on
the 1st fret of the sixth string, then move your finger up to the 2nd fret on
the same string, you’ve moved up in pitch one half step.

Whole Steps (Major second intervals): If you start with your first finger
on the 1st fret of the sixth string, then move your finger up to the 3rd fret
on the same string, you’ve moved up in pitch one whole step.


These terms will help us describe movement up and down the fretboard.

The following diagram can be referred to match up intervals with fret
distance from a given root note.
Scales And Keys

The key is the root of the scale that a group of chords or notes fall into.

For example, if you have three notes being played, let’s say they’re C, D,
and G, we know from the C major scale that this note sequence can be said
to be in (or derived from) the key of C.

Each key is going to be one of the seven musical notes or pitches that we
identified earlier. However, we need to keep in mind that scale notes are
then taken directly out of that key. Thus, any piece of music is based on a
scale, which has a key.

Were we to move the scale up or down the fretboard, the key would change.

Therefore, the more correct explanation is that our songs have keys, which
then indicate to us particular scales.

The mechanism is, Scales take their letter value from the root note or
“tonic” of the scale sequence.

Once you know what scale you’re playing and in what key, you can move the
scale or any segment of it to any location on the fretboard, thereby changing
its key.

Chromatic Guitar Scales

Western music uses 12 notes, which can be referred to as “The Complete
Chromatic Scale.” On a keyboard or piano, this is represented by seven
white keys and five black keys.

On a guitar, it’s represented by 12 frets.

The chromatic scale on the guitar can be visualized by going from the open E
on the sixth string to the 12th fret (high E) on the same string, at which
point the pattern simply repeats.

Those 12 notes make up the complete chromatic scale on the guitar.
In the above diagram, we’ve only gone to the 10th fret to save space in the
graphic but, the concept remains intact.

All the guitar scales you will ever see are derived from this simple 12-note
system. Moreover, all the different sounds, melodies, and arrangements we
get come from a variation of this sequence.

It is made up of two types of notes:

1.Naturals: These notes have only a letter value (A, B, C, D, E, F, G) and
neither flats nor sharps are attached to them.

2.Accidentals: They have a letter value and either a sharp or flat associated
with it, like B♭.

These make up all the musical notes in existence.

Although complex music theory isn't required to become a good guitarist,
understanding these musical concepts will help us know why we play what
we play and what all the movement on the fretboard actually means.

You can read more about guitar scale theory here. Applications of guitar scale theory are also discussed in this article.

Written by - Saija Bhumireddy

Edited by - Anusha Vajha

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