Understanding Keys

To understand music, it is necessary to understand what makes up a key more deeply than just what notes are in it. While a key is the group of notes that make up a scale, as we begin combining these notes in different ways, a key becomes much more than just seven notes. Within each key resides a "family of seven chords and seven corresponding scales. All of these are made up of the seven notes that make up the scale. In this lesson, we,ll explore this chord family and learn how to analyze a group of chords to determine their key. Previously, we built chords using the 1st., 3rd., 5th., and 7th., notes from the major scale. It is also possible to build chords from the other notes in the scale. Since there are seven notes in the scale, there are seven notes we can build chords from and, therefore, there are seven chords to a key. When we build chords, regardless of which note in the scale we build the chord from, the notes are always stacked in thirds. Written on the staff, this becomes clear.

		The lowest note in each of the chord stacks is that chord's "root." The rest of the chord is added by stacking every other note from the scale on top of the root.

When finding the names of each chord in the harmonized major scale, it is necessary to compare each of the chord stacks to a known chord built from the same root. In other words, if we know that the Cmaj7 chord is made up of the notes C, E, G and B (1, 3, 5, 7 from the C major scale). A comparison to the chord built from the note C (above) shows that chord to be the same. It is Cmaj7. (See below.) That one is obvious since it is the C major scale that we started with. But, when we look at the other chords, things can get a little confusing. The second chord is a D chord because it is built from D, but we don,t know what type of chord it is (major, minor, etc.).

			Identifying the Second Chord in a Key
			Since a major chord is constructed from the 1st., 3rd., 5th., and 7th. noted from a major scale, the first chord stack is obviousely major. The other chords need to be identified by comparing them to known chords. It's important to able to identify chords in a given key when soloing (improvising) or writing music.

	The process of identifying the second chord in C major

		The Harmonized C Major Scale These are all the chords in the key of C major. Although other keys are made up of different notes, the order of the types of chords derived from them are the same. All major scales are made up of the same chord types in the same order.
		It is typical to refer to the chords by the number in which they appear in the major scale (1 through 7). Usually Roman numerals are used to avoid confusion with the numbering of the individual notes within each chord. (I chord = maj7, ii chord = min7, iii chord = min7, IV chord = maj7, V chord = dom7, vi chord = min7, vii chord = min7(b5))

By going through the analization process, we can see that the chords in the key of C are Cmaj7, Dmin7, Emin7, Fmaj7, G7, Amin7, Bmin7(b5). As you work through all of the major scales, you will see that, even though the root notes change, the chord types always follow the same order regardless of the key. In other words, the I chord is always major 7, the ii chord is always minor 7, the iii is always minor 7, the IV is always major 7, the V is always Dominant 7, the vi is always minor 7, and the vii is always minor 7(b5).