Introduction
Music Theory and chord construction is very complex and exhaustive. Luckily as a guitarist, you generally don't need to know the half of it. However, it is important to know some basic chord theory & construction. In this section I have tried to explain as simply as I can the basics you should know as a guitarist.
Basics
In music there are 12 notes which is called the Chromatic Scale. The notes in the Chromatic Scale are as follows:
A A# B C C# D D# E F F# G G#
The # represents a sharp. The sharp (#) of a note is the same as the flat (b) of the note in front of it.
So A# is the same as B(b), C# is the same as D(b), F# is the same as G(b) etc.
So the above Chromatic Scale could also be written as:
A Bb C Db D Eb F Gb G Ab ...... both are exactly the same.
All scales such as the Major Scale, Minor Scale, Dorian Scale etc and modes are taken from the basic Chromatic Scale.
What Is A Chord?
A Chord is simply 2 or more notes shown above in the chromatic scale played or appeared to be played simultaneously to produce a musical sound.
The most common chords used in guitar playing are 2 noted chords ( also known as power chords or 5th chords and common to rock guitarists with distortion) and Triad chords (3 note chords). These are the very basics. These basic Chords can then be extended to produce Tetrad (4 note chords) such as 7ths, suspended, diminished, augmented chords etc.
Chord Constuction
A chord is constructed from the 8th degrees (notes) of the Diatonic major scale within an octive by using chord formulas.
Lets simplify this....
- The 12 note chromatic scale is A A# B C C# D D# E F F# G G#
- You will see that if we went to the 13th note, we would go back to A again...The distance between the first A and the 2nd A is an OCTAVE....So the 2nd A would be an OCTAVE higher than the 1st A.
- A scale is a combination of any of these notes, also called degrees.
- The major scale used for chord construction is known as a Diatonic scale which means 7 notes between the octave.....(although the 8 degrees (notes) refers to between the ROOT note and the 2nd Root note one octave higher).
Using the Diatonic Major Scale, we can then begin to construct a chord using Chord Formulas.
You may remember as a child or at school singing doh - ray - me - fah - so - la - ti - doh.
You may also see it written as do - re - mi - fa - so - la - ti - do
This is your major scale from which chords are constructed from and each represents a degree.
The fist note is established as the ROOT note and the 8th note is one octave higher and is the same note as the first. The chord is named the same as the root note. So a G chord starts with a root note being G, a D chord starts with a root note being D etc....However, there are variations because a chord can be a chord with a different starting note such as an E chord with a G bass...but we won't cover that in this section.
The chord is then constructed by using chord formulas from the major scale, starting at the ROOT note of the chord....so for any G chord we start with the G note (as G is the ROOT note) and use the G major scale, for any C chord we start with the C note (as C is the ROOT note) and use the C major scale to construct the chord etc.