Lesson Three

Introduction to Music Theory

In order to understand music, you only really need to know two things:

Know your letters from A to G
Be able to count from 1 to 12

Of course this is an oversimplified way of looking at it, but it is nevertheless true. All concepts in music theory boil down to these two abilities, so keep that in mind as you dive deeper down the rabbit hole of music theory – and remember to have fun along the way!

Introducing the Chromatic Scale:

The Musical Alphabet Consists of Tones and Semi-Tones:

a) A whole step in music is called a tone. That means you’re skipping a note on the piano’s keyboard, or skipping a fret on the guitar fretboard
b) A half step in music is called a semi-tone. This means you don’t skip a note or fret.

Introducing the Major Scale

The Major Scale is the main scale used in just about all forms of music. The major scale is the basis for playing songs in major keys, e.g. the key of A Major. It has a specific formula that stays the same, no matter what key you’re looking at:

Whole Step – Whole Step – Half Step – Whole Step – Whole Step – Whole Step – half Step

Here’s your first major scale on the guitar (a G Major Scale):

Here is the chart for all the major scales:

Scales 2 – Introduction to the Minor Scale

The Minor Scale is the basis for playing songs in minor keys, e.g. the key of Am. Just like the major scale, the minor scale has a specific formula, no matter what note you’re starting out with. The formula is as follows: Tone – Semitone – Tone – Tone – Semitone – Tone – Tone In terms of whole and half steps, it would be the following:

Whole Step – half Step - Whole Step – Whole Step – Half Step – Whole Step – Whole Step

The Harmonized Major and Minor Scale:

The chords you use to play in any key are based on the major scale of that key (or the minor scale, if you’re playing in a minor key).

Once you know the notes in the major scale of the key you want to play in, and you remember the “chord formula”, you will know which chords to use, no matter what key you are playing in. Here are the formulas for scale chords in major and minor keys:

Chord Formula (Major Key): Maj – Min – Min – Maj – Maj – Min – Dim

Chord Formula (Minor Key): Min – Dim – Maj – Min – Min – Maj – Maj

With this knowledge, you can play chords in any of the 12 keys. Here is a chart that combines everything you’ve learned so far:

But for simplicity’s sake, here are chords in keys charts for the major and minor scale, separately:

Remember this chart? I hope it all makes sense now:

Triads - Building Chords From Scratch

In lesson one, we learned that chords are made up of triads:

We will focus on Major, Minor, Diminished, Suspended, and 7th Chords

Diminished Chords

Diminished chords are chords that sound “more minor than minor”. A minor chord sounds “minor” or sad with respect to the major cord. Now the diminished chord sounds even gloomier, because now we’re flatting the 3rd and the 5th note. The VII chord in any harmonized major scale is always a Diminished chord.

When you look at the harmonized chromatic scale, things get even more interesting. The most common chord in the harmonized chromatic scale is the
diminished chord! Every sharp or flat note in between the notes of the major or minor scale, when harmonized, ends up being a diminished chord.

The main application of diminished chords are as passing chords. Diminished chords are mainly used as passing chords, either between the chords of the harmonized major or minor scale, or as a passing chord between the VI and I chords. Good examples are the VI – VII – I and IV – IV#dim – V progressions.

Here are some 4th, 5th, and 6th string Diminished chord shapes:

Major Seventh and Seventh Chords

Two of the most important harmonic chords are the 7th and major 7th Chords:

The 7th and Major 7th part of the names come from the scale interval the extra note added to the triad occupies on the chromatic scale. Recall scale intervals:

The Major 7th Chord is used primarily as a harmonic substitute chord for the I and IV chords. It gives a soft, dreamy, beautiful sound. Here are some major 7th open chord shapes:

Seventh chords, also known as dominant 7th chords, are used as harmonic substitutes for just about every major chord, and for some minor chords as well. Their most common uses however are the following:

Substituting V 7th for the V chord (e.g. G for G7), especially at the end of a musical section ( e.g. F – G7 – C)
Substituting I 7th for I in a I – IV progression (e.g. C7 – F)
As a substitute for the III chord in a I – III – VI progression (e.g. C – E7 –
Am), such as in What A Wonderful World
As a replacement for major triads in Blues and Jazz music (e.g. replacing A – D – E with A7 – D7 – E7)

Here are some dominant 7th chord shapes:

Suspended Chords

There are two types of suspended chords – suspended 2 (sus2) and suspended 4 (sus4) chords. The name “suspended” comes from the feeling you get when you hear the chord – it leaves you in suspense, waiting for the sound to be resolved back to the major triad.

Suspended chords are formed by replacing the 3rd interval with either the major 2nd or 4th interval to in major triad:

Here are some common suspended chord shapes:

Suspended chords are usually used to create variation in a piece of music. They can be used as substitutes for any of their respective major triads, but most often are used for the I, IV, and V chords.

Musical Notation – Reading Standard Music

Music is now written in a universal language, consisting of mainly the types of notes that are played, and the length of time that each note is played. For the purposes of learning guitar, we should have at least a basic understanding of standard notation, and a thorough grasp of guitar tablature.

We will begin with identifying notes along musical staves, otherwise known as standard musical notation. The musical stave looks something like this:

The following diagrams help to simplify the above diagram a little further:

I know this looks really complicated, but hang in there. There is a much easier way to remember which note belongs where on the musical staff, and it involves memorizing catch phrases for both the spaces and the lines on the staff:

To put what you have learned into practice, try this simple melody on the guitar:

The Circle of 4ths and 5ths – Understanding Key Signatures

The circle of 4ths and 5ths is a diagram used to help musicians understand the relationship between a key and the number of sharps or flats in the scale of that key. The diagram looks something like this:

The main application of the circle is to be able to recognize key signatures in musical notation. This key signature for example has 3 sharps:

Using the circle, we see that the key of A has 3 sharps in its scale.

As you go down the circle of fifths, the sharp being added is always a semitone below the actual key it belongs to. This is because the last step in the major scale is a half-step (semi-tone).

Study the circle of fiths (clockwise) carefully again. The first sharp, F#, is one half step below the actual key represented by the key signature of 1 sharp, which is the key of G. The next sharp, C#, is a semitone below D, the key represented by a key signature of 2 sharps.