1.6: Harmony
Most simply put, harmony is the way a melody is accompanied . While melody can be described as the horizontal aspect of music, harmony refers to the vertical aspect of music and is concerned with the different musical sounds that occur at the same moment.
Figure \(\PageIndex{1}\): Example of the relationships between melody and harmony.
Western music culture has developed a complex system to govern the simultaneous sounding of pitches. Some of its most complex harmonies appear in classical music, while other forms of popular music tend to have fewer and simpler harmonies.
We call the simultaneous sounding of three or more pitches a chord .
Chords can be consonant or dissonant . Consonant intervals and chords tend to sound sweet and pleasing to our ears. They also convey a sense of stability in the music. Dissonant intervals and chords tend to sound harsher to our ears, and often convey a sense of tension or instability. In general, dissonant intervals and chords tend to resolve to consonant intervals and chords. Seconds, sevenths, and tri-tones sound dissonant and resolve to consonance. While some of the most consonant intervals are unisons, octaves, thirds, sixths, fourths, and fifths. From the perspective of physics, consonant intervals and chords are simpler than dissonant intervals and chords. However, the fact that most individuals in the Western world hear consonance as sweet and dissonance as harsh probably has as much to do with our musical socialization as with the physical properties of sound.
Ex. 1.6.1 Examples of consonance and dissonance
The triad is a chord that has three pitches. The intervals (distance) between the notes changes the quality of the chord.
Figure \(\PageIndex{2}\): Triad chords in musical notation
On top of its root pitch is stacked another pitch at the interval of a third higher than the root. On top of that second pitch, another pitch is added, another third above. If you add a fourth pitch that is a third above the previous pitch, you arrive at a seventh chord . (You may be wondering why we call chords with three notes “triads” and notes with four chords “seventh chords.” Why not “fourth chords?” The reason has to do with the fact that the extra note is the “seventh” note in the scale from which the chord is derived. (We will get to scales shortly.) Seventh chords are dissonant chords. They are so common in jazz, however, that they do not always sound like they need to resolve to consonant chords, as one might expect. One also finds chords with other additional tones in jazz: for example, ninth chords, eleventh chords, and thirteenth chords. These chords are related by stacking additional thirds on top of the chord.
Key (sometimes called “tonality”) is closely related to both melody and harmony. The key of a song or composition refers to the pitches that it uses. A key is a collection of pitches, much like you might have with a collection of stamps, bottles, etc. The most important pitch of a key is its tonic, that is, the note from which the other pitches are derived. For example, a composition in C major has C as its tonic; a composition in A minor has A as its tonic ; a blues in the key of G has G as its tonic. A key is governed by its scale . A scale is a series of pitches, ordered by the interval between its notes. There are a variety of types of scales. Every major scale, whether it is D major, C major, or G-sharp major, has pitches related by the same intervals in the same order. Likewise, the pitches of every minor scale comprise the same intervals in the same order. The same could be said for a variety of other scales that are found in jazz, rock, and popular music, including the blues scale and the pentatonic scale.
| C major scale | C | D | E | F | G | A | B | C | ||
| A minor scale | A | B | C | D | E | F | G | A | ||
| Blues/Rock scale on A | A | C | D | E | G | A |
Table \(\PageIndex{1}\): C major scale, A minor scale, Blues scale on A
Major and minor scales are most often found in Western music today. The difference in quality between the major scale and the minor scale is in the perception of the sound. Major sounds relatively bright and happy. “Happy birthday” and “Joy to the World” (the Christmas Carol) are based on the major mode.
Ex. 1.6.2: Examples of the major and minor modes
You might note that the simplest form of the blues scale (Table 1.1) is a type of pentatonic or five-note scale. This reflects the origins of the blues in folk music; much of the folk music around the world uses pentatonic scales. You might also note that the blues scale on A, has a note suspended below it, an E-flat (a pitch that is a half-step higher than D and a half-step lower than E). Otherwise, it is devoid of its blue notes. Blue notes are pitches that are sometimes added to blues scales and blues pieces. The most important blues note in the key of A is E-flat. In a sense, blues notes are examples of accidentals. Accidentals are notes that are not normally found in a given key. For example, F-sharp and B-flat are accidentals in the key of C. Accidentals are sometimes called chromatic pitches: the word chromatic comes from the ancient Greek word meaning color, and accidentals and chromatic pitches add color and excitement to a composition.
Chords can be built on every pitch of a scale. See Table 1.2 for the triads of C major.
| C | D | E | F | G | A | B |
| E | F | g | A | B | c | D |
| G | A | b | C | D | e | F |
| I | ii | iii | IV | V | vi | vii |
Table \(\PageIndex{2}\): Chords of C Major
One can build seventh chords on these same pitches, by simply adding pitches. In the key of C major, the C major triad is considered the tonic triad (I), because it is built on the tonic of the key. Every other chord in C major tends to resolve to the tonic chord. The two next important chords are the F chord, which we call the IV chord or subdominant, and the G chord, which we call the V chord or dominant. Popular music also uses the VI chord a lot. The chords of a key tend to progress in an orderly fashion. Certain chords tend to resolve to other chords. The dominant or V chord normally resolves directly to the tonic or I chord. We call a series of chords a chord progression .
One of the most important chord progressions for jazz and rock is the blues progression.
In the blues, the tonic chord (I) moves to the subdominant chord (IV) and then back to the tonic chord (I) before moving to the dominant chord (V) and finally back to the tonic (I). This often happens in the space of twelve bars or measures and thus this progression is sometimes called the twelve-bar blues. In the key of D, it would look like the following--
| Root of the chord | D | G | D | A | G |
| Chord Symbol | I | (IV) | I | V | (IV) |
| Number of bars | 4 | 2 | 2 | 2 | 2 |
Table \(\PageIndex{3}\): Twelve-bar blues in the key of D
As you can see, sometimes the dominant chord (V) briefly shifts back to the subdominant chord (IV) before finally resolving to the tonic chord. Chord progressions play a major role in structuring jazz, rock, and popular music, cueing the listener to beginnings, middles, and ends of phrases and the song as a whole. Chord progressions in particular, and harmony in general, may be the most challenging aspects of music for the beginner. Hearing chords and chord progressions requires that one recognize several music phenomena at the same time. Chords may change rapidly, and a listener has to be ready to move on to the next chord as the music progresses. The best way to learn to hear harmonies is to start with simple examples and ask general questions. Listen to the infamous performance on the Ed Sullivan Show of “Light My Fire” (1967) by the Doors, below. See if you can hear the general difference between the verses, which use mostly minor chords, and the chorus, which uses mostly major chords. If you continue to listen, you will eventually be able to hear both.
Ex. 1.6.3: The Doors, “Light my Fire” (1967)