Basic Chord Theory

Now that we know our intervals, let's apply this knowledge and build chords.
A loose definition for a chord is any combination of notes heard together, but certain notes sound better together than others.
The following is the theory behind finding notes that sound good together.
Most chords consist of 3 important notes called a TRIAD. This triad determines the QUALITY of the chord. There are 4 main chord triads: Major , Minor , Diminished and Augmented.

For information on Diminished chords and Dominant 7 chords, please check out my book. (Augmented chords will be covered in Volume II)

Major

A major chord consists of the notes 1,M3,P5.
NOTE: any chord that doesn't have a quality after it is assumed to be a major chord. i.e.: a "C" chord is the same as a "C" major chord.
Applying these intervals to C major, we would get C as 1, E as 3 and G as 5.
A "C" major chord is made up of only C,E,G notes.
If I play just these 3 notes IN ANY ORDER on my instrument, I will be playing a "C" major chord.
The lowest sounding note (also known as the bass note) should be 1 (Root). Later, we'll discuss inversions.
This could be a "C" chord on a guitar:

E 0---|---|---|---
B |---|---|---|---
G 0---|---|---|---
D |---|---|---|---
A |---|---|-3-|---
E |---|---|---|---

It consists of all the notes that make a "C" chord, but it sure would be hard to strum.

To make life easier, we can DOUBLE any note in a chord. This would explain the more popular version of the C chord:

E 0---|---|---|---
B |-1-|---|---|---
G 0---|---|---|---
D |---|-2-|---|---
A |---|---|-3-|---
E |---|---|---|---

In this version, the C and E notes are doubled.
In order from the lowest note to highest we get - C,E,G,C,E.
The intervals would be 1,3,5,8,10, but since 8 is the same as 1 and 10 is the same as 3, we don't have to include these intervals in the formula.
The notes of a chord can be played and/or doubled in any octave as long as they equal their basic interval name.

Let's look at some more examples:

Ex. 1
What are the notes of a B chord ?

We know the formula is 1,3,5.
B is 1. D# is 3. F# is 5.
The notes of a B chord are B,D#,F#.

Ex. 2
What is this chord called?

E |---|-1-|---|---|
B |---|---|---|-4-|
G |---|---|---|-3-|
D |---|---|---|-2-|
A |---|-1-|---|---|
E |---|---|---|---|

2nd fret, A string is a "B"
4th fret, D string is a "F#"
4th fret, G string is a "B"
4th fret, B string is a "D#"
2nd fret, E string is a "F#"

What chord has B in the bass and B,D#,F# notes ?
That's right, a "B" chord.
In this case, the intervals are 1,5,8,10,12.
8 is the same as 1. 10 is 3. 12 is 5.

Ex. 3
Is this a major chord ? Why ?

E |---|---|---|---|
B |---|---|---|-3-|
G |---|---|---|-3-|
D |---|-1-|---|---|
A |---|-1-|---|---|
E |---|---|---|---|

No. It has B which is the Root (1). E is a 4th. B is 8th (R). D# is a 3rd (10th).
This chord is made up of 1,4,8,10 or simply 1,3,4.
A major chord has to have 1,3,5 !

Test your knowledge of the major chord in Chord Quiz #1

Minor

A minor chord consists of the notes 1,m3,P5.
NOTE: "m" means minor. This is used for both chords and intervals.
Applying these intervals to C minor, we would get C as 1 (Root), Eb as m3 (b3) and G as 5.
A "C" minor chord is made up of only C,Eb,G notes.
If I play these 3 notes on my instrument, I will be playing a C minor chord.
Remember to keep the bass note as 1.
This could be a "Cm" chord on a guitar:

E |---|---|---|---
B |---|---|---|-2-
G 0---|---|---|---
D |---|---|---|---
A |---|---|-1-|---
E |---|---|---|---

It consists of all the notes that make a "Cm" chord, but to make it easier to strum and fuller sounding, we can DOUBLE any note in the chord.

This would explain the more popular version of the Cm chord:

E |---|---|-1-|---|---|---|---
B |---|---|---|-2-|---|---|---
G |---|---|---|---|-4-|---|---
D |---|---|---|---|-3-|---|---
A |---|---|-1-|---|---|---|---
E |---|---|---|---|---|---|---

In this version, the C and G notes are doubled.
In order from the lowest note to highest we get - C,G,C,Eb,G.
The 5th and Root are the doubled notes in this example.
Let's look some more examples:

Ex. 1
What are the notes of a Bm chord ?

We know the formula is 1,b3,5.
B is 1. D is 3. F# is 5.
The notes of a Bm chord are B,D,F#.

Ex. 2
What is this chord called?

E |---|-1-|---|---|
B |---|---|-2-|---|
G |---|---|---|-4-|
D |---|---|---|-3-|
A |---|-1-|---|---|
E |---|---|---|---|

2nd fret, A string is a "B"
4th fret, D string is a "F#"
4th fret, G string is a "B"
4th fret, B string is a "D"
2nd fret, E string is a "F#"

What chord has B in the bass and B,D,F# notes ?
That's right, a "Bm" chord.
In this case, the intervals are 1,5,8,b10,12.
8 is the same as 1. b10 is b3. 12 is 5.

Ex. 3
Is this a minor chord ? Why ?

E |---|---|---|---|
B |---|-1-|---|---|
G |---|---|---|-3-|
D |---|---|---|-3-|
A |---|-1-|---|---|
E |---|---|---|---|

No. It has B which is the Root (1). F# is a 5th. B is 8th (R). C# is a 9th (2nd up octave).
This chord is made up of 1,5,8,9.
A minor chord has to have 1,m3,5 !

Test your knowledge of the minor chord in Chord Quiz #2.

For information on Diminished chords and Dominant 7 chords, please check out my book. (Augmented chords will be covered in Volume II)

Back to table of contents