A key consists of a group of notes
and the chords derived from that group of notes. A key also has
one primary note and one primary chord that is build from that
note. All other notes and chords are heard in relationship to
this primary note/chord. This primary note is the key center,
or tonal center. The group of notes that is used
in a key is called a scale.
The focus of this lesson is to take a look at major
keys. The key that uses the major scale as its group of notes.
A key is just a flavor or color of sound. A song may stay in one
key, or it may change many times throughout.
For this lesson we are going to first look at the
key of C major. As you learned in the basic
chord construction lesson, the basic chords built from a C
major scale are C, Dm, Em, F, G, Am, and Bo. Each chord
has a function within the key. The word function
just means that each chord has a unique sound in relationship
to the main chord of the key. The main chord in a key is called
the tonic chord, and in this case that is a C major.
To show how each chord functions in the key, Roman
numerals are used as a way to both indicates the degree of the
scale that a chord is built on, and the chord quality (major,
minor, etc.) A Roman numeral by itself like I, IV,
or V indicates a major chord. A small m after it means
that the chord is minor. So IIm, IIIm, and VIm
are all minor chords. The small circle after the Roman numeral
will indicate a diminished chord, like VIIo.
functions in the key of C major
C D E
F G A
B - C major scale
| | | | | | | C Dm Em F
G Am Bo
- Chord Name I IIm*
IIIm IV V VIm
VIIo - Function
classical theory uses a lower case Roman numeral to indicate a
minor chord function....ii, iii, vi. And the small m is not used.
It more modern theory...Jazz, Rock, and other contemporary music,
chord functions use capital Roman numerals. Then a small m is
used if the chord is minor, a small circle is used for diminished,
and there are other modifiers as well that will tell you what
the quality of the chord is. (Ex. IIm, IIsus2, II7)
The harmonization (creation of chords or harmony)
of a major scale will always follow the same pattern, no matter
what major key you are in. The basic chord build on the 1st degree
of the scale is major, the 2nd is minor, the 3rd is minor, the
4th is major, the 5th is major, the 6th is minor and the 7th is