Harmonic function is a denomination that represents the sensation (emotion) that a certain chord transmits to the listener. This concept will become clearer when we show you the examples. First, know that the three main harmonic functions are the following:
Transmits a feeling of rest, stability and tranquility. Promotes the idea of completion.
Conveys a feeling of instability and tension. Promotes the idea of preparation for the tonic.
Is the middle ground between the two previous functions. It can be said that it generates a feeling of preparation, but with less intensity, being able to migrate both to the dominant function (intensifying the tension) and to the tonic (resting).
Playing the harmonic functions
To better understand what we’re talking about, try playing the following chords repeatedly, in the order they appear below:
| Gmaj7 | Cmaj7 | D7 |
As you play this sequence slowly, notice how the D7 chord feels “ready” to return to the Gmaj7. This sound of instability is characteristic of the dominant function. Upon returning to the Gmaj7 chord, there is a feeling of “relief”, “resolution” and stability. This is characteristic of the tonic function.
The Cmaj7 chord in this context, however, represented a middle ground (without all the distress of the D7, but also without the stability of the Gmaj7). This characterizes the subdominant function.
We can generalize this experiment by saying that, in any major key: the 1st chord characterizes the tonic function, the 4th chord (4th degree) characterizes the subdominant function and the 5th chord characterizes the dominant function.
As said above, that each chord has a harmonic function in music, we will summarize the functions of each degree of the major key below:
Note: the III degree can also act as dominant, as it is the relative chord of the dominant function, despite not having the tritone.
Great, so the ideas that we show of “completion” and “preparation” can exist not only with degrees I, IV and V, but also with the other degrees, according to this table. This is very important! We will start using this concept of harmonic functions for everything from now on in the next topics and modules. Therefore, it is essential that you memorize well the function of each degree of the major key, immediately identifying who is dominant, subdominant or tonic.
Each of these degrees is also rated for “functional quality”. This functional quality is what represents the strength of each degree in relation to its harmonic function, that is, it informs which degrees solve or prepare with more or less force.
The main function chords (I, IV and V) are called strong chords; chords II and VII (which are substitutes for IV and V, respectively) are called medium-strong; and the remaining chords of tonic function (III and VI) are called weak.
When we speak of substitute degrees, we are saying that we can exchange chords that have the same harmonic function.
This means that we can take the chords of a song and exchange them for others that have the same harmonic function without changing the feel of the song! See below, as an example, the functions of the C major key:
Note: some authors argue that there is no medium-strong function, only strong and weak (whatever is not strong, is weak).
You can play with a song that is in the key of C major by switching the chords that are in the same row in this table. For example, in place of the F chord that appears in the song, you can place the Dm chord, and the same goes for the other functions.
To test these concepts, take songs you know and analyze them from the point of view of harmonic functions. Identify each chord in the song with its respective degree and function, as listed here.
Also, try to identify the sensation of the song at that given moment. This will be your “homework”.
You can also try replacing the chords with the same harmonic function between them, but for now, don’t worry so much about it. We will work a lot on the subject of harmonic functions further on; this topic is just an introduction.
However, you will like to know that harmonic functions are the great secret of musicians who have a great ear. By knowing well the sensation that each of these 3 functions have (tonic, dominant and subdominant), it becomes much easier to identify a certain chord by ear. The dominant function, for example, is (in the opinion of many) the easiest to identify.
Let’s say you’re playing a song you don’t know with a band and someone tells you that the song’s key is C major. You are at the back of the stage and cannot see the chords that the vocalist is playing on his instrument. In short, you are playing the song by ear on the spot.
Suddenly, you feel that a particular chord has the dominant function (this is easy to recognize with a little experience and ear training). Since you know that the function is dominant and that the key is C major, it means that the chord in question can be V7 degree or VIIm7(b5).
It is much more common for V7 to appear than VIIm7(b5), so you would try to play G7 and have a 99% chance of getting it right. Even if you made a mistake, you would make mistakes within the same harmonic function, which is tolerable, because the sensation these chords give is the same (the sound would not be out of place).
Without knowing the feel of the harmonic functions, this task would be much more difficult, as you would need to know the sound of each chord individually and, if you made a mistake, you would risk playing a chord with another harmonic function, which would be disastrous.
Manipulation of emotions
In addition to this application, harmonic functions also serve to manipulate people’s emotions. Everyone feels tense with music characteristic of thriller films, right? Well, they are nothing more than an abuse of dominant chords, which are hammering on without ever settling in the tonic.
On the other hand, television advertisements seek to emphasize soft and pleasant sensations (tonic function) so that the customer feels comfortable and associates this well-being with his product.
Artists try to manipulate the harmonic functions according to the lyrics of the song. If the lyrics are saying something bad or worrying, the feeling is that of a dominant chord. When the lyrics are resolved and the song is “happier”, harmony accompanies this evolution with the tonic function.
In this way, the message is experienced by the listener twice, since the meaning of the lyrics and the sensation of the song add up. Good composers, arrangers and producers are usually experts in this subject.
Any study on harmony, improvisation or composition will intrinsically address the theme of harmonic functions, so it is necessary to master this subject now.
In improvisation, it is easy to understand that if a song is transmitting tension, the solo also needs to highlight tension. If the song is transmitting serenity, the solo also needs to highlight serenity.
A soloist who follows what the song imposes creates melodies that are very pleasant to our ears, because there is a perfect marriage between melody and harmony.
We can compare this to a soccer game, where the right winger (harmony) crosses the ball into the area and the forward (melody) runs in and heads the ball into the goal. If the winger retreats the ball, should the forward run into the area and head nothing? Likewise, if the winger crossed the ball into the box, the forward could not return to midfield!
Although obvious, this type of error is very common in improvisation. But rest assured, let’s work here so that you can play well in this team!
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