Idiot's Guides - Music Theory
Page 14
The rule here is that the V chord naturally leads back to the I chord. Although you can write another chord after a V, the best resolution is to follow the V with the I.
Other chords also have related chords that they naturally lead to. Some chords can even lead to more than one chord. To learn which chords lead where, take a look at the following table.
Chord Leading Reference
These Chords …
Lead to These Chords …
I
Any chord
ii
IV, V, vii°
iii
ii, IV, vi
IV
I, iii, V, vii°
V
I
vi
ii, IV, V, I
vii°
I, iii
Although there are exceptions to these rules, you can create a pleasing chord progression by following the order suggested by this chart. This means if you have a iii chord, you follow it with either a ii, IV, or a vi chord. Or if you have a vi chord, you follow it with either a ii, IV, V, or I chord, and so on.
Let’s put together some of these combinations. We’ll start, of course, with the I chord. Because I leads to any chord, let’s go up one scale note and insert the ii chord after the I. According to our chart, ii can lead to either IV, V, or vii°. We’ll pick V. Then, because V always leads to I, the next chord is a return to the tonic.
The entire progression looks like this:
I ii V I
When you play this progression in the key of C, you get the following chords:
C / / / Dm / / / G / / / C / / /
Sounds good, doesn’t it?
Let’s try another example. Again, we’ll start with the tonic, but this time we’ll use the vi chord as the second chord. According to the chart, vi can lead to either ii, IV, V, or I; let’s pick IV. Then, because IV can lead to either I, iii, V, or vii°, we’ll pick V as the next chord—which leads us back to I as our final chord.
The entire progression looks like this:
I vi IV V I
When you play this progression in the key of C, you get the following chords:
C / / / Am / / / F / / / G / / / C / / /
You should recognize that progression as the chords that drove thousands of doo-wop tunes in the 1950s and 1960s.
Let’s return to that progression, and make an alternate choice for the third chord—ii instead of IV. Because ii also leads to V, we can leave the rest of the progression intact, which creates the following alternate progression:
I vi ii V I
This, when played in the key of C, results in these chords:
C / / / Am / / / Dm / / / G / / / C / / /
TIP
When you’re playing a chord progression, the number of beats or measures allotted to each chord isn’t set in stone. For example, you could play the I-IV-V progression with a single measure for each chord. Or you could play two measures of I, and a measure each of IV and V. Or you could play three measures of one and then two beats each of IV and V. It all depends on the needs of the song—and helps provide an almost infinite variety of possible chord combinations.
You can also work backward from where you want to end up—your final chord. Because in most cases you want the final chord to be the tonic (I), all you have to do is work through the options that lead to that chord. Consulting the Chord Leading Reference table, you find that four chords can lead to the I: IV, V, vi, 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, 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, called a perfect cadence, is notated V-I. In the key of C, it 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).
TIP
The V-I progression can be enhanced by using the dominant seventh chord (V7) instead of the straight V. This progression is notated V7-I.
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, typically by ending on the V (dominant) triad.
This type of ending progression is called an imperfect cadence, and you can get to the V chord any number of ways—I-V, ii-V, IV-V, and vi-V being the most common. In the key of C, these progressions look like this:
I-V:
C / / /
G / / /
ii-V:
Dm / / /
G / / /
IV-V:
F / / /
G / / /
vi-V:
Am / / /
G / / /
Interrupted Cadence
Even less final than an imperfect cadence is an ending progression called an interrupted cadence. In this progression, you use a V chord to trick the listener into thinking a perfect cadence is on its way, but then move to any type of chord except the tonic.
V-IV, V-vi, V-ii, and V-V7 progressions all are interrupted cadences—and, in the key of C, look like this:
V-IV:
G / / /
F / / /
V-vi:
G / / /
Am / / /
V-ii:
G / / /
Dm / / /
V-V7:
G / / /
G7 / / /
NOTE
In classical music theory, an interrupted cadence is more often called a deceptive cadence.
Common Chord Progressions
Given everything you’ve learned about chord leading and cadences, you should be able to create your own musically sound chord progressions. However, just in case you get stuck, let’s take a look at some of the most popular chord progressions used in music today.
I-IV
It doesn’t get much simpler than this, just the tonic (I) and the subdominant (IV) chords repeating back and forth, over and over. This is a cyclical progression, good for songs that don’t really have a final resolution point.
In the key of C, the progression looks like this:
C / / / F / / /
I-V
If you can cycle between the tonic and the subdominant (IV), why not the tonic and the dominant (V)? Like the first progression, the simplicity of this one makes it quite common in folk and some forms of popular music.
In the k
ey of C, the progression looks like this:
C / / / G / / /
Unlike the I-IV progression, this one has a bit more finality, thanks to the V-I relationship. But since you keep going back to the V (and then the I, and then the V again, and then the I again, and on and on), it still is very cyclical sounding.
I-IV-V
You can’t get any more popular than the old I-IV-V progression. This is the progression (in the key of G) you’re playing when you strum the chords G, C, and D on your guitar.
There are many different variations on the I-IV-V progression. You can leave out the IV, insert an extra I between the IV and the V, and even tack on another I-V at the end to wrap things up with a perfect cadence. You also can vary the number of beats and measures you devote to each chord.
One example of I-IV-V in a four-measure phrase might look like this, in the key of C:
C / / / C / / / F / / / G / / /
You could also bunch up the IV and the V into a single measure, like this:
C / / / C / / / C / / / F / G /
The progression also could be used over longer phrases, as in this eight-measure example:
C / / / C / / / C / / / C / / /
F / / / F / / / G / / / G / / /
TIP
This progression is often played with a dominant seventh chord on the fifth (V7), which provides increased tension before you return to the tonic.
The point is, these three chords are used in a huge number of modern songs—and make up the core of what many refer to as “three-chord rock and roll.” They’re not limited to rock, of course; many folk, country, jazz, rap, and even classical and show tunes are based on these three chords.
It’s an extremely versatile progression.
I-IV-V-IV
This progression is a variation on I-IV-V. The variation comes in the form of a shift back to the subdominant (IV), which then forms a plagal cadence when it repeats back to the tonic. In the key of C, the progression looks like this:
C / / / F / / / G / / / F / / /
It’s a nice, rolling progression—not too heavy—without a strong ending feeling to it—which makes it nice for tunes that repeat the main melody line again and again.
I-V-vi-IV
This progression is another rolling one, good for repeating again and again. (That’s because of the ending plagal cadence—the IV repeating back to I.)
In the key of C, it looks like this:
C / / / G / / / Am / / / F / / /
I-ii-IV-V
This progression has a constant upward movement, resolved with a perfect cadence on the repeat back to I. In the key of C, it looks like this:
C / / / Dm / / / F / / / G / / /
I-ii-IV
This is a variation on the previous progression, with a soft plagal cadence at the end (the IV going directly to the I, no V involved). In the key of C, it looks like this:
C / / / Dm / / / F / / /
As with all progressions that end with a plagal cadence (IV-I), this progression has a rolling feel, and sounds as if it could go on and on and on, like a giant circle.
I-vi-ii-V
This was a very popular progression in the 1950s, the basis of a lot of doo-wop and jazz songs. It’s also the chord progression behind the song “I’ve Got Rhythm,” and sometimes is referred to (especially in jazz circles) as the “I’ve Got Rhythm” progression.
In the key of C, it looks like this:
C / / / Am / / / Dm / / / G / / /
I-vi-IV-V
This is a variation on the “I’ve Got Rhythm” progression, with a stronger lead to the V chord (IV instead of ii). It looks like this, in the key of C:
C / / / Am / / / F / / / G / / /
This progression was also popular in the doo-wop era and in the early days of rock and roll. The defining factor of this progression is the descending bass line; it drops in thirds until it moves up a step for the dominant chord, like this: C-A-F-G. You’ve heard this progression (and that descending bass line) hundreds of times; it’s a very serviceable progression.
I-vi-ii-V7-ii
This is another variation on the “I’ve Got Rhythm” progression, with an extra ii chord squeezed in between the final V and the return to I, and with the V chord played as a dominant seventh. In the key of C, it looks like this:
C / / / Am / / / Dm / / / G7 / Dm /
By adding the ii chord between the V7 and the I, almost in passing, it takes the edge off the perfect cadence and makes the progression a little smoother.
IV-I-IV-V
As this progression shows, you don’t have to start your chord progression on the tonic. In the key of C, it looks like this:
F / / / C / / / F / / / G / / /
This progression has a bit of a rolling nature to it, but also a bit of an unresolved nature. You can keep repeating this progression (leading from the V back to the IV), or end the song by leading the progression home to a I chord.
NOTE
The IV-I-IV-V progression is also frequently played at the end of a phrase in many jazz tunes. Used in this manner, it’s called a turnaround. (See Chapter 16 to learn more.)
ii-V-I
This progression is quite popular in jazz, often played with seventh chords throughout. So you might actually play a ii7-V7-I progression, like this (in the key of C):
Dm7 / / / G7 / / / CM7 / / /
Sometimes jazz tunes cycle through this progression in a variety of keys, often using the circle of fifths to modulate through the keys. (That’s the term you use any time you change the key within a song.)
Circle of Fifths Progression
There’s one more chord progression that’s fairly common, and it’s based on the circle of fifths you learned about back in Chapter 4. Put simply, it’s a progression where each chord is a fifth above the next chord; each chord functions as the dominant chord for the succeeding chord. The progression circles back around on itself, always coming back to the tonic chord, like this: I-IV-vii°-iii-vi-ii-V-I.
Here’s what the progression looks like in the key of C:
C / / / F / / / Bdim / / / Em / / / Am / / / D / / / G / / / C / / /
You can also play this progression backward, creating a circle of fourths, but that isn’t nearly as common as the one detailed here.
Chromatic Circle of Fifths
The circle of fifths progression we just discussed is a simple one you can use without getting into nonscale chords. But there’s also another, longer, circle of fifths progression, based on chromatic chords, that you might want to play around with.
This progression is a little too complex to write out in Roman numeral notation, but it works by having each chord function as the precise subdominant of the next chord—that is, the chords move in perfect fifths around the chromatic scale. Even more fun, each chord is turned into a dominant seventh chord, to make the dominant-tonic relationship more explicit.
Here’s how it looks, in the key of C:
C / / /
C7 / / /
F / / /
F7 / / /
Bb / / /
Bb7 / / /
Eb / / /
Eb7 / / /
Ab/ / /
Ab7 / / /
Db / / /
Db7 / / /
Gb / / /
Gb7 / / /
B / / /
B7 / / /
E / / /
E7 / / /
A / / /
A7 / / /
D / / /
D7 / / /
G / / /
G7 / / /
C
You can jump on and off this progression at any point in the cycle. Kind of neat how it circles around, isn’t it?
Singing the Blues
There’s a unique chord progression associated with the genre of music we commonly call the blues. This blues form isn’t relegated solely to blues music, however; you’ll find this form used in many jazz and popular tunes, as well.
The blues progression is a 12-measure pro
gression. (It’s sometimes called a “12-bar blues.”) This 12-measure progression repeats again and again throughout the melody and any instrumental solos.
The form is essentially a I-IV-I-V7-I progression, but spread over 12 measures, like this:
I / / /
I / / /
I / / /
I / / /
IV / / /
IV / / /
I / / /
I / / /
V7 / / /
V7 / / /
I / / /
I / / /
In the key of C, the blues progression looks like this:
C / / /
C / / /
C / / /
C / / /
F / / /
F / / /
C / / /
C / / /
G7 / / /
G7 / / /
C / / /