The Complete Idiot''s Guide to Music Theory

Chapter 10:Chord Progressions 133

and vii°. The obvious choice is the V chord, so that’s what we’ll use. Now we have
to pick a chord to lead to V; the choices are ii, IV, vi, and I. Let’s pick ii. Now we
pick a chord that leads to the ii; the choices are I, iii, IV, and vi. Let’s pick iii. Now
we pick a chord that leads to the iii; the choices are I, IV, and vii°. Let’s pick I,
which is also a good chord with which to start our phrase. When you put all these
chords together, you get the following progression:

I iii ii V I

Play this progression in the key of C, and you use these chords:

C / / / Em / / / Dm / / / G / / / C / / /

Pretty easy, isn’t it?

Ending a Phrase

When you come to the end of a musical phrase—which can be anywhere in your song,
even in the middle of your melody—you use chords to set up a tension, and then
relieve that tension. This feeling of a natural ending is called cadence, and there are
some accepted chord progressions you can use to provide this feeling of completion.

Perfect Cadence

The most common phrase-ending chord progression uses the V (dominant)
chord to set up the tension, which is relieved when you move on to the I (tonic)
chord. This progression is notated V-I, and in the key of C looks like this:

G / / / C / / /

You could probably see this cadence coming, from the chord leading shown in
the table named Chord Leading Reference earlier in this chapter. There’s no
better way to get back home (I) than through the dominant chord (V).

Plagal Cadence

A slightly weaker ending progression uses the IV (subdominant) chord in place of
the V chord. This IV-I progression is called a plagal cadence;in the key of C, it
looks like this:

F / / / C / / /

Although this is an effective cadence, it isn’t nearly as strong as the perfect V-I
cadence. For that reason, you might want to use a plagal cadence in the middle of
your song or melody, and save the stronger perfect cadence for the big ending.

Imperfect Cadence

Sometimes, especially in the middle of a melody, you might want to end on a chord
that isn’t the tonic. In these instances, you’re setting up an unresolved tension, typi-
cally by ending on the V (dominant) triad.

The V-I progression

can be enhanced

by using the domi-

nant seventh chord

(V7) instead of the straight

V. This progression is

notated V7-I.

Tip