Idiot's Guides - Music Theory
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The difference between a ninth chord and a triad with an added ninth.
TIP
Added notes can be notated by the word add plus the number, or just the number—within parentheses.
There are an endless number of possibilities you can use when working with altered chords. You can even include more than one variation per chord—all you have to do is keep adding the variations onto the end of the chord notation. Just remember to start with the base chord and make your alterations as clear as possible. (And, if all else fails, you can write out the notes of the chord on a staff—just to make sure everybody understands.)
Suspended Chords
We’re so used to hearing a chord as a 1-3-5 triad that any change to this arrangement really stands out like a sore thumb to our ears. (Not that you should put your thumbs in your ears, but you know what I mean.) This is what makes a suspended chord so powerful, especially when used properly.
A suspended chord temporarily moves the normal major third of a major chord up a half step to a perfect fourth. This suspension of the second note of the triad is so wrong to our ears, we want to hear the suspension resolved by moving the second note down from the fourth to the third—as quickly as possible.
For example, a C suspended chord includes the notes C F G—instead of the C E G of C Major. This sets up an incredible tension, as the fourth (F) sounds really out of place; your ears want the F to move down to the E to create the more soothing C Major triad.
In fact, most often you do resolve suspended chords—especially at the end of a musical phrase. You can use the suspended chord to set up the desired end-of-phrase tension, but then quickly resolve the suspended chord to the normal major chord, like this:
Resolving a suspended chord—the F in the first chord drops down to the E in the final chord.
NOTE
As you can see from the example, you notate a suspended chord with the phrase sus4, or more simply sus.
The resolution from the perfect fourth to the major third is just a half-step movement, but that little half step makes a world of difference; until you make the move, you’re sitting on the edge of your seat waiting for that incredible tension to resolve.
Power Chords
If you want a really simple chord, one with a lot of raw power, you can play just the root and the fifth, leaving out the third. This type of chord is called a power chord; it is noted by adding a “5” after the chord note. (For example, a G power chord is notated G5, and includes only the notes G and D.) Power chords are used a lot by guitarists in certain types of popular music, in particular the hard rock and heavy metal genres.
NOTE
In classical music theory, a power chord is called an open fifth, and is technically an interval, not a chord.
Here’s one bad thing about power chords: if you use a bunch of them in a row, you create something called parallel fifths. As you’ll learn, parallel fifths are frowned upon, especially in classical music theory. So use power chords sparingly and—if at all possible—not consecutively.
Power chords, up and down the scale.
Inverting the Order
Although it’s easiest to understand a chord when the root is on the bottom and the fifth is on the top, you don’t have to play the notes in precisely this order. Chords can be inverted so that the root isn’t the lowest note, which can give a chord a slightly different sound. (It can also make a chord easier to play on a piano, when you’re moving your fingers from chord to chord; inversions help to group the notes from adjacent chords closer together.)
When you rearrange the notes of a chord so that the third is on the bottom (3-5-1), you form what is called the first inversion. (Using a C Major chord as an example, the first inversion is arranged E G C.) The second inversion is where you put the fifth of the chord on the bottom, followed by the root and third (5-1-3). (Again using C Major as an example, the second inversion is arranged G C E.) The standard triad form, with the root on the bottom, is called the root inversion.
The first and second inversions of a C Major chord.
If you’re working with extended chords, there are more than two possible inversions. For example, the third inversion of a seventh chord puts the seventh in the bass; the fourth inversion of a ninth chord puts the ninth in the bass.
The particular order of a chord’s notes is also referred to as that chord’s voicing. You can specify a voicing without writing all the notes by adding a bass note to the standard chord notation. You do this by adding a slash after the chord notation, and then the name of the note that should be played on the bottom of the chord.
For example, if you want to indicate a first inversion of a C Major chord (normally C E G, but E G C in the first inversion), you’d write this: C/E. This tells the musician to play a C Major chord, but to put an E in the bass—which just happens to be the first inversion of the chord. If you wanted to indicate a second inversion (G C E), you’d write this: C/G. This tells the musician to play a C Major chord with a G in the bass.
You also can use this notation to indicate other, nonchord notes to be played in the bass part. For example, Am7/D tells the musician to play an A minor seventh chord, but to add a D in the bass—a note that doesn’t exist within the A minor seventh chord proper.
An A minor seventh chord with a D in the bass—not your standard seventh chord.
WARNING
Don’t confuse the chord/bass notation with the similar (like a fraction with a horizontal divider, as opposed to the chord/bass diagonal slash). The notation tells a musician—typically a pianist—to play one chord over another. For example, if you see you should play a Cm chord with your right hand, and a Dm chord with your left.
Adding Chords to Your Music
When you want to indicate a chord in your written music, you add the chord symbol above the staff, like this:
Write the chord symbol above the staff.
The chord applies in the music until you insert another chord. Then the new chord applies—until the next chord change. For example, in the following piece of music you’d play a C Major chord in measure 1, an F Major chord in measure 2, a C Major chord in the first half of measure 3, a G7 chord in the second half of measure 3, and a C Major chord in measure 4.
Changing chords in your music.
If you’re writing a part for guitar, or for a rhythm section (bass, piano, and so forth) in a pop or jazz band, you don’t have to write out specific notes on the staff. A guitarist will know to strum the indicated chords, a piano player will know to comp through the chord progressions, and the bass player will know to play the root of the chord.
DEFINITION
Comping is a technique used by jazz and pop musicians to play an improvised accompaniment behind a particular piece of music. A piano player might comp by playing block or arpeggiated chords; a guitarist might comp by strumming the indicated chords.
You write a comp part by using slashes in place of traditional notes on the staff. Typically, you use one slash per beat, so a measure of 4/4 will have four slashes, like this:
Writing chords for a rhythm section.
You can indicate specific rhythms that should be played by writing out the rhythm, but with slashes instead of note heads. The result looks something like this:
Indicating a specific rhythm for the chord accompaniment.
If you’re writing specifically for guitar, you also have the option of including guitar tablature. (A guitar part with tablature is sometimes called guitar tab.) Tablature shows the guitarist how to fret the chord, and is very useful for beginning-level players. More advanced players probably don’t need this assistance, unless you’re indicating a particularly complex chord.
A guitar part with tablature added.
NOTE
If you go to idiotsguides.com/musictheory, you’ll find a comprehensive reference to just about every kind of chord you can think of—major chords, minor chords, extensions, you name it. You’ll find out how to construct each chord, lea
rn the guitar tablature, and discover alternate ways to describe the chord. Keep this website bookmarked—you’ll get a lot of use out of it!
Exercises
Exercise 9-1
Name the following major chords.
Exercise 9-2
Name the following minor chords.
Exercise 9-3
Write the following major chords on the staff.
Exercise 9-4
Write the following minor chords on the staff.
Exercise 9-5
Name the following extended chords.
Exercise 9-6
Write the following extended chords on the staff.
Exercise 9-7
Write the first and second inversions of the following chords.
Exercise 9-8
Resolve the following suspended chords by lowering the suspended note (the middle note of the chord) to the note a half step below.
The Least You Need to Know
A chord consists of three or more notes (called a triad) played simultaneously—with each note typically a third above the previous note.
A major chord includes the root note, a major third, and a perfect fifth.
A minor chord includes the root note, a minor third, and a perfect fifth.
Extensions above the basic triad are typically added in thirds, and can be either major or minor.
A minor seventh chord is a minor triad with a minor seventh; a major seventh chord is a major triad with a major seventh; a dominant seventh chord is a major triad with a minor seventh.
When you play a chord with a note other than the root in the bass, you’re playing a chord inversion.
When you write for guitar, piano, or bass, you don’t have to write out all the notes; all you have to do is specify the chord, along with rhythmic slashes on the staff.
CHAPTER
10
Chord Progressions
In This Chapter
Understanding scale-based chords
Learning the rules of chord leading
Figuring out how to end a progression
Discovering the most common chord progressions
Fitting chords to a melody—and a melody to a chord progression
In Chapter 9, you learned how to group notes together to form chords. Individual chords alone are interesting, but they become really useful when you string them together to form a succession of chords—what we call a chord progression. These chord progressions provide the harmonic underpinning of a song, “fattening out” the melody and propelling the music forward.
Of course, to create a chord progression that sounds natural, you can’t just string a bunch of chords together willy-nilly. Certain chords naturally lead to other chords; certain chords perform distinct functions within a song. You have to use your chords properly, and arrange them in the right order, to create a piece of music that sounds both natural and logical.
Chord progressions don’t have to be complex, either. The simplest progressions include just two or three chords—which are easy enough for any beginning guitarist to play. How many songs, after all, do you know that use only the G, C, and D chords? (A lot, I bet.) Those three chords comprise one of the most common chord progressions—which should show you how easy all this is.
Chords for Each Note in the Scale
To better understand the theory behind chord progressions, you need to understand that you can create a three-note chord based on any of the seven notes of a major key or scale. You start with the note of the scale (one through seven) as the root of the chord; then build up from there in thirds—using only the notes within the scale.
Let’s use the key of C as an example, because it’s made up of only the white keys on a piano. When you play a triad based on C (the tonic of the scale), you play C E G—a C Major chord. Now move up one white key on the keyboard, and play the next triad—D F A, or D minor. Move up another key, and you play E G B, the E minor chord. Move up yet another key, and you play F A C—F Major. Keep moving up the scale and you play G Major, A minor, and B diminished. Then you’re back on C, and ready to start all over again.
This type of chord building based on the notes of a scale is important, because we use the position within a scale to describe the individual chords in our chord progressions. In particular, we use Roman numerals (I through VII) to describe where each chord falls in the underlying scale. Uppercase Roman numerals are used for major chords; lowercase Roman numerals are used for minor chords. To indicate a diminished chord, you use the lowercase Roman numeral plus a small circle (a degree sign: °). To indicate an augmented chord, use the uppercase Roman numeral plus a small plus sign.
Thus, within a major scale, the seven chords are notated as follows:
I ii iii IV V vi vii°
If you remember back to Chapter 2, each degree of the scale has a particular name—tonic, dominant, and so on. We can assign these names to the different chords, like this:
I
ii
iii
IV
V
vi
vii°
Tonic
Supertonic
Mediant
Subdominant
Dominant
Submediant
Leading Tone
Of these chords, the primary chords—the ones with the most weight—are the I, IV, and V. These also are the only major chords in the major scale—and often the only chords used within a song.
When describing chord progressions, we’ll refer to chords by either their Roman numerals or their theoretical names (tonic, dominant, and so forth). You can figure out which specific chords (C Major, D minor, and so forth) to play, based on the designated key signature.
To make things easier, you can refer to the following table, which lists the seven scale-based chords for each major key signature.
Scale-Based Chords
Key Signature
Chords
C
C#
D♭
D
E♭
E
F
F#
G♭
G
A♭
A
B♭
B
C♭
Creating a Progression
Let’s see how you can use these Roman numerals to create a chord progression. For the time being we won’t pay attention to the underlying harmonic theory; we’ll just concentrate on the mechanics of creating a progression.
I mentioned earlier the popularity of the G, C, and D chords. In the key of G Major, these chords happen to fall on the first (G), fourth (C), and fifth notes of the scale. This makes these the I, IV, and V chords—or, more technically, the tonic, subdominant, and dominant.
If you’ve ever played any rock, country, or folk songs, you know that one of the more common chord progressions goes like this:
G / / / C / / / G / / / D / / /
(Naturally, the progression repeats—or ends with a final G chord.)
NOTE
These examples use slash notation, where each slash (/) equals one beat. Measures are separated by spaces.
Because you know that the G = I, C = IV, and D = V, it’s easy to figure out the Roman numeral notation. It looks like this:
I IV I V
There—you’ve just written your first chord progression!
The benefit of using this type of notation is you can apply the chord progression to other keys. Let’s say you want to play this I-IV-I-V progression in the key of C. Referring back to the Scale-Based Chords table earlier in this chapter, you can translate the progression to these specific chords:
C / / / F / / / C / / / G / / /
This definitely makes things simpler.
It’s All About Getting Home
The goal of most major chord progressions is to get back to the home chord—the tonic chord, or I. All the other chords in the progression exist as part of a roadmap to deliver you back to the I chord. The route can be simple
(just a chord or two) or complex (lots and lots of different chords), but ultimately you want to end up back on I.
As you’ll learn in the next section, certain chords naturally lead to the I chord. In addition, you can employ multiple-chord progressions to get you back to I—these are called cadences and are also discussed later in this chapter.
One Good Chord Leads to Another
Although you can write a song using any combination of chords that sounds good to your ears—even chords from other keys—in most cases chord progressions are based on a few simple rules. These rules come from a concept called chord leading, which says that certain chords naturally lead to other chords.
You can hear chord leading for yourself by playing some chords on the piano. To keep it simple, we’ll stay in the key of C—so you don’t have to play any of the black keys.
Start by playing a C Major chord (C-E-G). This is the I chord, which doesn’t necessarily lead anywhere because, based on chord-leading rules, the I chord can be followed by any chord in the scale.
Now play a G Major chord (G-B-D). This is the V chord in the scale, and it definitely wants to go somewhere. But where? You could follow it with an F Major chord (F-A-C), but that isn’t fully satisfying. Neither is D minor (D-F-A) or E minor (E-G-B) or even A minor (A-C-E). The only chord that sounds fully satisfying—the chord that V naturally leads to—is the I chord, C Major.