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An Introduction to Music Theory

Part Two


Welcome to the second part of the "trilogy" of lessons on music theory. At this moment, I'm not sure how many parts the trilogy will run to. In an attempt to prevent an information overload, successive parts of the lesson focus on one or two topics. This part covers intervals and the location of notes. Following parts will therefore cover chords, modes and other scales and then I will pull everything together for lead playing and soloing. Location of Notes on a Guitar Before we concern ourselves with intervals, we need to consider individual notes and where they are located on the guitar fretboard. The diagram below shows this. In order to fit on the page, the zero fret (or open string) and 12th fret are shown separately. The pattern of notes is therefore repeated starting at the thirteenth fret.

|--E--|  (1st string - thinnest)
|--E--|  (6th string - thickest)
 0 & 12

   1     2     3     4     5     6     7     8     9     10    11
  (13)  (14)  (15) etc.

Obviously it is desirable to know all notes in all positions, but this is something that takes a long time to achieve. The best method is to approach one string at a time. For instance, starting with the 6th string (E), play the open string and then each ascending note up to the 12th fret. Say (or sing) each note as you play it, to help speed up the learning process.

An alternative method I saw in a guitar magazine lesson (by Joe Satriani) used a metronome set to 60, and a note chart like the one above. Firstly choose a note. Start on the sixth string and play that note in all positions, including the open string if applicable. Then, without missing a beat, move to the 5th string and find that note in all positions again. Play on the beat, continuing for the other four strings also. If 60 is too fast slow it down; if it is too slow speed it up. Practice with all 12 notes until you can do it in your sleep!


The following discussion considers single notes although exactly the same principles apply to chords.

Intervals basically describe the "musical distance" between two notes or chords.

As we saw in the first part, the major scale has the following structure -

Scale Degree 1 2 3 4 5 6 7  
The C major scale C D E F G A B C
Chord Type maj min min maj maj min dim  
Interval T T S T T T S  

The interval between successive notes in a major scale is either a semitone or a tone. A semitone is called a minor 2nd interval and a tone is called a major 2nd interval. We can thus describe a major scale relative to the root note in terms of major 2nd and minor 2nd intervals -

C - D = major 2nd
C - E = major 3rd
C - F = perfect 4th (normally just called 4th)
C - G = perfect 5th (normally just called 5th)
C - A = major 6th
C - B = major 7th
C - C = octave

As you might expect, these intervals are all major intervals. However for chord formation we also need to consider minor intervals. Additionally, there are two other interval names that only apply to the perfect fourth and perfect fifth interval. If either of these are sharpened by a semitone then they are termed "augmented". If they are flattened by a semitone they are called "diminished".

So why should we concern ourselves with intervals? As musicians, it would be ideal to have perfect pitch so that you know exactly which notes or chords are being played. There are courses available that offer this, but a simple and free method that can be used to improve your ear training is to learn to hear intervals. Although this is not the same as perfect pitch, if you can recognise intervals you will be able to transcribe from CDs much more quickly and accurately.

The standard tuning of a guitar as shown above is E A D G B E. If we refer to the cycle of fifths -

1 2 3 4 5 6 7 8
G A B C D E F# G
D E F# G A B C# D
A B C# D E F# G# A
E F# G# A B C# D# E
B C# D# E F# G# A# B
F# G# A# B C# D# F F#
C# D# F F# G# A# C C#
G# A# C C# D# F G G#
D# F G G# A# C D D#
A# C D D# F G A A#
F G A A# C D E F

We can see that E - A is a perfect fourth; A - D is a perfect fourth; D - G is a perfect fourth; G - B is a major 3rd and B - E is a perfect fourth. The following diagrams show commonly used intervals for the key of C with the root note on the 3rd fret of the A string.

Major 2nd

E  |---|---|---|---|---|---|
B  |---|---|---|---|---|---|
G  |---|---|---|---|---|---|
D  |---|---|---|---|---|---|
A  |---|---|-X-|---|-X-|---|
E  |---|---|---|---|---|---|

Minor 3rd                         Major 3rd

E  |---|---|---|---|---|---|   E  |---|---|---|---|---|---|
B  |---|---|---|---|---|---|   B  |---|---|---|---|---|---|
G  |---|---|---|---|---|---|   G  |---|---|---|---|---|---|
D  |-X-|---|---|---|---|---|   D  |---|-X-|---|---|---|---|
A  |---|---|-X-|---|---|---|   A  |---|---|-X-|---|---|---|
E  |---|---|---|---|---|---|   E  |---|---|---|---|---|---|

Perfect fourth 

E  |---|---|---|---|---|---|
B  |---|---|---|---|---|---|
G  |---|---|---|---|---|---|
D  |---|---|-X-|---|---|---|
A  |---|---|-X-|---|---|---|
E  |---|---|---|---|---|---|

Perfect fifth

E  |---|---|---|---|---|---|
B  |---|---|---|---|---|---|
G  |---|---|---|---|---|---|
D  |---|---|---|---|-X-|---|
A  |---|---|-X-|---|---|---|
E  |---|---|---|---|---|---|

Major 6th                         or

E  |---|---|---|---|---|---|---|   E  |---|---|---|---|---|---|
B  |---|---|---|---|---|---|---|   B  |---|---|---|---|---|---|
G  |---|---|---|---|---|---|---|   G  |---|-X-|---|---|---|---|
D  |---|---|---|---|---|---|-X-|   D  |---|---|---|---|---|---|
A  |---|---|-X-|---|---|---|---|   A  |---|---|-X-|---|---|---|
E  |---|---|---|---|---|---|---|   E  |---|---|---|---|---|---|

Minor 7th                         Major 7th

E  |---|---|---|---|---|---|   E  |---|---|---|---|---|---|
B  |---|---|---|---|---|---|   B  |---|---|---|---|---|---|
G  |---|---|-X-|---|---|---|   G  |---|---|---|-X-|---|---|
D  |---|---|---|---|---|---|   D  |---|---|---|---|---|---|
A  |---|---|-X-|---|---|---|   A  |---|---|-X-|---|---|---|
E  |---|---|---|---|---|---|   E  |---|---|---|---|---|---|


E  |---|---|---|---|---|---|---|
B  |---|---|---|---|---|---|---|
G  |---|---|---|---|-X-|---|---|
D  |---|---|---|---|---|---|---|
A  |---|---|-X-|---|---|---|---|
E  |---|---|---|---|---|---|---|

Because intervals are relative, you can move the starting note to a different fret on the A string to play intervals in that key. For instance if you play the above patterns relative to the fifth fret, you will be playing intervals in the key of D; play relative to the seventh fret and you are playing intervals in the key of E. It is also good practice to play these intervals with the root note on a different string to familiarise yourself with the positions of the notes and the different pitches on different parts of the fretboard.

I would suggest that the intervals that you should start with are the major 3rd and minor 3rd. When you can hear the difference, you have taken your first tentative steps towards being able to work out songs by ear.

If you have any comments or suggestions, feel free to mail me: (

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