A melody line can be played in such a way as to sound perfect all alone, but rarely are they performed that way. Chords add depth to a song and aid the flow of the melody line. Chords can be play together or broken in single notes called arpeggios. They can be inverted to produce a completely different sound, become minor, diminished or augmented.
Chords are created by playing three or more notes from the scale. The notes can be played together or broken up with individual timing. The lowest note of the chord is the root. The major third of the scale is added as well as the perfect fifth to create a major chord. The primary chord of a composition would be the chord with the scale name as the root. The primary chord in the key of C would consist of a C, E and G. For many pop, country and rock compositions the primary chord as well as the fourth (F, A, C) and fifth (G, B, D) chords makes up the majority of the chords used.
Chords can be inverted to create a different feel to the piece. A first inversion places the third of the chord on the bottom of the chord. In a C chord this would place the E as the bottom note. A second inversion places the fifth on the bottom of the chord. This is useful for switching between the first and fifth chord as the bottom note remains the same.
Minor chords are chords with flattened thirds. Most commonly used minor chords are rooted on the second and sixth notes of the scale. The most commonly used chord progression would have a second chord resolving to the fifth chord making the progression sound complete. The sixth generally leads to the second or fourth. Diminished chords are minor chords with a flattened fifth as well.
Chords can have notes added to them beyond the root, third and fifth. Adding the seventh note of the scale is a common transition between chords. The seventh is flatted then added to the top of the chord. When inverted it retains its place in the order of the scale. Adding the fourth of the scale to a chord and allowing it to resolve to the third note is a popular chording option for the endings of songs.
Augmented and diminished chords are also used to make the music behind the melody more interesting. Diminished chords are minor chords with a flattened fifth as well. Augmented chords are major chords that have the fifth note of the scale raised a half step. Augmented chords are often used when changing from the primary chord to the fourth chord.
Chords are named by their root. A G chord contains a G, a B and a D. Add the seventh to that and it is notated like this: G7. To the primary chord an F natural would be adding to make the seventh. When the chord is to be minor it would be notated with a lowercase m. An E minor chord would be notated like this: Em. A number after the chord simply means to add that number from the scale to the chord to be played. An A6 would contain an A, C#, E and F#.
Knowing the basic patterns of chord progressions will allow the key of a song to easily be changed to meet the needs of vocalist and instrumentalist. Piano chord charts can be found online that are invaluable when composing or transposing a piece.