Guitar Music Theory 101

Guitar music theory is a subject that a lot of guitarists ask about.

In this post you will start with very easy guitar theory and as I add more videos to the Modern Guitar Harmony Youtube channel you will learn more advanced guitar theory.

You must know one very important thing before we start and this comes directly from jazz guitar great Frank Vignola whom I organised a guitar workshop for. Frank said “Be able to play the theory!”

It’s no use knowing every mode of the harmonic minor scale for example if you can’t even play the harmonic minor scale on the guitar. Therefore each lesson also has a practical element. It is very important to practise these exercises.

This Guitar Music Theory 101 post goes hand in hand with the Ear Training 101 post. Study both simultaneously.

If you have any questions contact us through the Contact Form which is found in the header.

Anyhow, without further ado, let’s get started.

 

Guitar Music Theory Lesson 1

The Musical Alphabet / Chromatic Scale

Music consists of notes and these notes form a musical alphabet as follows;

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

There are 12 notes.

Notice that the B and E notes don’t have sharps (the word BE), conversely the notes C and F don’t have flats.

The # symbol is a sharp and raises the previous note by one fret.

The b symbol is a flat and lowers a note by one fret.

After the G#/Ab you go back to the start but an octave higher.

For visualisation purposes the A note is your open A string.

The A#/Bb is on the first fret, A string, the B note is on the second fret, A string and the C note is on the third fret, A string.

As you follow the notes up the A string you will find yourself on the A note on the 12th fret of the A string where the notes repeat.

The above notes played from A to A is actually a scale called the chromatic scale.

The A# and Bb are two names for the same pitch, they both sound the same. and are called enharmonic notes.

There are two notes for one sound as these relate to scales. You will learn later that it’s easier to read music with less sharps and flats. For now just roll with it.

Practical

Before moving on learn the above notes all over the guitar neck. There are lots of Youtube videos etc use these to learn the notes on the fretboard as quickly as possible.

Also ear training is super, super important. Sing the chromatic scale as you play it in a register that suits your voice. I can not emphasise how important this is. You will thank me in a few years, guaranteed!

 

Guitar Music Theory Lesson 2

The Major Scale Formula

The major scale isn’t just composed from a random bunch of notes. There is a formula that you can use when working out what the major scale is in a key.

The major scale formula is this;

Tone  Tone  Semitone  Tone  Tone  Tone  Semitone

A semitone is a half step or the distance of 1 fret.

A tone is a step or the distance of 2 frets.

Look at the musical alphabet again and to construct an A major scale let’s start with the A note.

With the A note as your starting point, your open A string for example, you need to move up a tone from A as a tone is the first step in the major scale formula.

A tone, or two frets, up from A gives you the B note.

Looking at the major scale formula you can see that we need to move up a tone, or two frets, from the B note. This gives you the C# note on the 4th fret of the A string.

Next you need to move up a semitone or 1 fret from the C# note. This gives you the D note on the 5th fret of the A string.

Now you need to move up a tone again (2 frets) from the D note which gives you the E note on the 7th fret, A string.

From the E note you need to move up another tone to the F# on the 9th fret and from the F# you need to move up another tone to the G# on the 11th fret on the A string.

Finally you need to move up a semitone, one fret, from the G# to the A note on the 12th fret.

Viola, by following the major scale formula you have now constructed an A major scale.

Practical

Try to work out the D major scale on the D string by following the major scale formula of Tone, Tone, Semitone, Tone, Tone, Tone, Semitone.

Also work out the G major scale on the G string.

Now play the major scale up and down one of those strings and sing the scale as you play it. Those with a lower voice might find the major scale on the A string more suitable, those with a higher voice might prefer to sing the major scale on the D or G strings.

Next, depending on your ability with the above, try to write something, or improvise something, with one of the above scales on one string (if you can’t do this or are daunted by it there’ll be more on this subject in future lessons).

For those a little more advanced write or improvise using the A major scale on the A string for 2 bars then change to the D major scale on the D string for 2 bars.

Answer

Like the A major scale you should be playing the D and G major scales on the open string, 2nd fret, 4th fret, 5th fret, 7th fret, 9th fret, 11th fret and 12th fret of each string.

The D major scale is spelled D, E, F#, G, A ,B, C#, D

The G major scale is spelled G, A, B, C, D, E, F#, G

 

Guitar Music Theory Lesson 3

Intervals

Intervals are a very important thing to understand when it comes to music theory as intervals make up melodies and chords.

An interval is the distance from one pitch to another pitch. The interval from the A note the B note above is called the major 2nd for example. it doesn’t matter if the A and B notes are played together or separately the interval is still a major 2nd.

Here is the list of intervals, within the octave, using the musical alphabet as seen in lesson 1.

The fret distance of the interval is listed in the brackets.

A – A = unison (0 because it’s the same note)

A – A# = minor 2nd (1)

A -B = major 2nd (2)

A – C = minor 3rd (3)

A – C#= major 3rd (4)

A – D = perfect 4th (5)

A – D# = b5 or tritone (6)

A – E = perfect 5th (7)

A – F = minor 6th (8)

A – F# = major 6th (9)

A – G = minor 7th (10)

A – G# = major 7th (11)

A – A (one octave higher) = octave (12)

 

Here are the intervals on the A string but you can start on any note and the intervals will be the same. For example from the B note to the C# note is a major 2nd interval.

 

Intervals are classed as consonant and dissonant. The unison, perfect 4th, perfect 5th and octave are very consonant intervals which means that the notes of those intervals sound nice together. Play an octave and notice how smooth those notes sound.

The minor 2nd and major 7th intervals are definitely dissonant.

The other intervals range from somewhat consonant to somewhat dissonant.

I’m hesitating to group these intervals as I want you to hear these sounds for yourself and much of their sound is dependent on which other notes and intervals are used around these intervals.

For example even a perfect 4th can sound dissonant when played amongst the other very consonant sounds.

Practical

Sing The Intervals

If I had to give just one piece of advice to a musician it would be to sing everything that you play.

It is super important to sing these intervals in order to get the sound of them into your ear.

Start by singing the perfect 5th, then the perfect 4th followed by the major and minor 3rd because once you have these sounds in your ear you can start singing arpeggios and their inversions.

Don’t worry if you don’t understand this yet, just sing intervals on a daily basis until the sound of the intervals is in your ear. A good test of this is singing these intervals accurately away from the guitar.

There is much more to learn about intervals but the above is plenty to know for now.

 

Guitar Music Theory Lesson 4

Constructing  a Triad with the Major Scale Formula

Now you can put lessons 1-3 to good use and construct a triad with the major scale formula.

A triad is a 3 note chord.

Let’s pick the key of C since there are no sharps or flats in this key.

Using the major scale formula of tone, tone, semitone, tone, tone, tone, semitone we get the following notes in the C major scale.

C D E F G A B C

Typically tertian, also called  tertiary harmony is used to construct triads and chords. Tertiary, as you may know means thirds or the third of something.

When constructing a triad or chord with tertiary harmony we have to go up in thirds.

Let’s make a C major triad and you’ll see how this works.

Obviously you have to start with the C note since the C note is the ‘root’ note of the C major chord.

From the C note you have to go up a third.

From C to D is a major second.

From C to E is a major 3rd. Since C to E is a major 3rd and we are building a chord in thirds we keep the E as the second note of the chord.

You now have the notes C and E.

The next step is to see which note from the C major scale is a third above E.

E to F is a minor second.

E to G is a minor third. Since G is a third above E you now have your third note of the C major triad.

The C major triad is spelled C E G.

If you play the typical open C major chord but only the A,D and G strings, you are playing the C,E and G notes which is your C major triad.

Here is how to play the C major triad on the A, D and G strings.

Practical

Try to construct a G major triad starting from the G note.

Answer

The G major scale is spelled G, A, B, C, D, E, F#

The root, 3rd and 5th of the G major triad are G, B and D

Therefore if you play the G, B and D notes anywhere on the guitar neck you are playing a G major triad.

Here are 3 possibilities. All these G major triads are spelled G, B, D.

 

Guitar Music Theory Lesson 5

Harmonizing the C Major Scale

In guitar music theory lesson 4 you constructed a triad on the first note of the C major scale.

This triad was a C major triad.

If we apply the same principle of skipping a note and selecting the next note (moving up in thirds) we get the following triads of the C major scale.

C E G = C major

D F A = D minor

E G B = E minor

F A C = F major

G B D = G major

A C E = A minor

B D F = B diminished

The Difference Between Major and Minor Triads

The major triads are major because they have a major third (which is a distance of 4 frets from the root note remember).

The minor triads are minor because they have a minor third (which is a distance of 3 frets from the root note ).

The C major triad is spelled C E G. The distance from the C to the E note is a major third hence the triad is major.

The D minor triad is spelled D F A. The distance from the D to the F is a minor third hence the triad is minor.

The Diminished Triad

The B triad when the C major scale is harmonized is a funny one.

The B diminished triad is spelled B D F.

Diminished means made smaller and a diminished triad is a type of minor triad.

The distance from B to D is a minor third this gives you a type of minor triad.

The distance from D to F is also a minor third whereas in a typical minor triad the interval from the middle note to the last note is a major third.

You can also say that the distance from B to F is a flat 5 (b5) or a tritone instead of a more typical perfect 5th.

So, you can see that this B diminished triad has been made smaller than the typical minor triad.

Triad Chord Scales

When you play the above triads from C to C (so C, Dm, Em, F etc) you are playing a triad chord scale.

The formula for triad chord scales is always the same for a major key and matches the pattern above which is;

Major – minor – minor – major – major – minor – diminished

When you play triad scales you might run out of space on the neck if you are just going up three strings. This means that you might have to change your string set as the following example shows.

Practical

First work out the G major scale using the major scale formula.

Next harmonize the G major scale with triads as you did with the C major scale in this lesson.

Also practise playing triads all over the neck. The Mick Goodrick Almanacs will definitely help with that.

Download Volume 1 on the Modern Guitar Harmony Resources Page.

Answers

Don’t scroll down if you don’t want to see the answers.

The G major scale is spelled;

G – A – B – C – D – E -F# – G

When the G major scale is harmonized you get the following triads.

G B D = G major

A C E = A minor

B D F# = B minor

C E G = C major

D F# A = D major

E G B = E minor

F# A C = F# diminished

Guitar Music Theory Lesson 6

Triad Inversions

The triads that you worked out in lesson 5 are called root position triads because the root of the triad is in the bass (the lowest voice). The root note is the main note. For example the C note in a C major triad is the root note.

A C major triad is spelled C E G and this is a root position triad.

However, you can also take the C note and put it on top of the triad so that it becomes the highest voice.

The C major triad is now spelled E G C and this is known as a first inversion triad.

From the first inversion triad which is spelled E G C you can take the E note and move it up to the highest voice.

The C major triad is now spelled G C E and this is known as a second inversion triad.

Practical

Take the C major or G major triads in root position (which you have worked out in the previous lessons) and work out the triad scales in first and second inversion triads.

Tip; try to work these out on the G B and E strings as beginners will find the triads on these strings most useful.

 

Guitar Music Theory Lesson 7

The Natural Minor Scale

In the second guitar theory lesson above you learned how to construct a major scale.

Now you will learn two ways to construct a natural minor scale.

The First Way to Construct the A Natural Minor Scale

The first way to construct a natural minor scale is that you can just play the major scale from the 6th note to the same note an octave higher.

The A major scale is spelled A B C# D E F# G# A

You can see that the 6th note is F# so if you play F# G# A B C# D E F# you are playing the F# natural minor scale.

Another way of picturing this is that if you want to solo over an F# minor chord you can do so with the A major scale but making the F# note the main note. As an aside the A and C# notes are the 3rd and 5th of the chord and will also sound great over an F# minor chord. Remember F# A C# spell an F# minor triad.

The Natural Minor Scale Formula

The second way of constructing a natural minor scale is with the natural minor scale formula which is;

Tone – Semitone – Tone – Tone –  Semitone – Tone – Tone

F# – G# – A – B – C# – D -E – F#

If you have been learning the above lessons properly you can see each of the interval distances between the notes of the scale.

This lesson has focused on the natural minor scale. There are many more minor scales such as the melodic minor scale, the harmonic minor scale, the hungarian minor scale and many more. Don’t worry about the other scales just yet.

The Relative Minor Scale

You can see how the F# natural minor scale was derived from the A major scale. You can say that the F# natural minor scale is the relative minor of the A major scale.

The relative minor scale starts on the 6th note of the major scale.

So the relative minor scale of the C major scale is the A minor scale as A is the sixth note of the C major scale.

The relative minor scale of the G major scale is the E minor scale.

In the diagram of the circle of fifths in the next lesson you can see the relative minor scale of each key

Practical

Beginners: Play up and down the A string making the F# note the main note. Try to make up little melodies around the F# note

Intermediates: Put on a Youtube backing track in F#m and improvise over the backing track using the F# natural minor scale using any scale positions that you know (all scale positions will be covered later).

 

Guitar Music Theory Lesson 8

The Circle of Fifths

 

The circle of fifths as seen above is also known as the circle of fourths.

If you start from the C at the 12 o’clock position and move clockwise you’ll see that the G is next. As you learned in the interval section the distance from a C note to the G note is a fifth.

Hence if you move clockwise you are using the circle of fifths.

However, if you move in an anti-clockwise direction you are using the circle of fourths. This is because the interval from the C to the F is a distance of a fourth.

Uses of the Circle of Fifths

One use of the circle of fifths is to use it to write all or part of a song.

Hey Joe most famously performed by Jimi Hendrix just moves up the circle of fifths.

The Hey Joe chord progression is C / G / D / A /E / E. As you can see this chord progression follows the circle of fifths exactly.

Uses of the Circle of Fourths

The circle of fourths is also used in song writing especially in the jazz idiom. For example in the bridge of the tune ‘I’ve Got Rhythm’ in the key of Bb the chord progression goes;

D7 / D7 / G7 /G7 / C7 / C7 / F / F

You can see that if you start on the D and move anticlockwise in the circle of fourths diagram you follow this chord progression exactly!

Other Uses of the Circle of Fifths

A great way for beginners to use the circle of fifths is to find the notes all over the guitar neck.

First find the C notes all over the guitar neck, then find the G notes, then the D notes etc.

Intermediate guitarists can use the circle of fifths in a variety of ways.

They can play scales in one position using the circle of fifths and they can also play triads and chords in one position of the fingerboard using the circle of fifths.

Relative Keys on the Circle of Fifths

You might read about keys in music or music keys.

When you are playing with the C major major scale you are playing in the key of C.

So, a piece of music might be composed of notes that belong to the C major scale. This piece of music is said to be in the key of C.

The C at the top of the circle of fifths represents the key of C. if you move to the right, to the G, the G is the key of G etc.

You saw in lesson 7 that the relative minor of A is F# (because you play the A major scale but from F# to F#).

If you look at the circle of fifths again you can see that underneath the C is an Am, A minor is the relative minor of C.

Similarly, you can see the F# underneath the A because F# is the relative minor of A.

Practical

Use the circle of fifths to find the notes on the guitar , use it to practise different scale fingerings in one position or to write a short piece of a song depending on your playing ability.

 

Guitar Music Theory Lesson 9

Playing Triads Through Cycles

It is important to learn how to play triads and chords through cycles especially if you want to learn where everything is on the fretboard.

The examples above of ”Hey Joe’ and ‘I Got Rhythm’ show just how important cycles are.

A cycle is just moving a triad up by a certain interval as the following examples in the key of C show;

Cycle 2 = Moves up in seconds = C D E F G A B C

Cycle 3 = Moves up in thirds = C E G B D F A C

Cycle 4 = Moves up in fourths = C F B E A D G C

Cycle 5 = Moves up in fifths = C G D A E B F C (Cycle 5 is cycle 4 descending)

Cycle 6 = Moves up in sixths = C A F D B G E C (Cycle 6 is cycle 3 descending)

Cycle 7 = Moves up in sevenths = C B A G F E D C (Cycle 7 is cycle 2 descending)

 

Guitar Music Theory Lesson 10

Voice-Leading

When you played the triads in the previous lesson you probably moved up and down the fretboard a lot in order to find the triads.

In this lesson you combine all 3 triad inversions to play some smooth sounding music.

Voice-leading is when the notes of one triad move the shortest possible distance to the notes of the next triad.

For example if you have to move from a C major triad to an F major triad you can keep the C note the same as this is a common tone between the two chords. You can then change the other two notes.

The C  major triad is spelled C E G.

The F major triad is spelled F A C.

C is the common tone so the E changes to the F note and the G note changes to the A note as follows.

 

You can see that movement between the two triads has been kept to a minimum.

At this stage you should really dive into the first volume of the Mick Goodrick almanacs. The first section of this book deals with voice-led triads in the key of C.

In closing you should now that  there are two more types of triads. Both of which are found in the Mick Goodrick almanacs linked above.

Closed Triads

All the triads that you have played above have been closed triads. This means that all the notes of the triad fall within the span of an octave.

Open or Spread Triads

Open triads, also known as spread triads, extend beyond the octave.

If we take the C major triad again you  know that it is spelled C E G.

However if we take out the middle note, the E note, and move it up an octave we get a C spread triad as the following diagram shows.

You can see from the example above why spread triads are called spread triads. It’s because the voices of the triad are spread out.

Guitarists that use a lot of spread triads in their playing are Eric Johnson and Pat Metheny (amongst many others!).

Tom Lippincott Guitar Music Theory Videos

Here are four music theory videos for guitar by jazz guitar educator and Modern Guitar Representative Tom Lippincott.

Guitar Harmony Basics Video 1

 

Guitar Harmony Basics Video 2

 

 

Guitar Harmony Basics Video 3

 

 

Guitar Harmony Basics Video 4

 

 

Modern Guitar Harmony Resources Page

For intermediate and advanced guitar theory check out the Modern Guitar Harmony Resources page.

Advanced Guitar Music Theory

Jack Pezanelli had a great view of using triads over bass notes as non-functional reharmonisation.

It’s such an interesting area to delve into. Read our blog post about Jack’s process here.