Functional harmony is a term used to describe the relationships between chords in music. It refers to the idea that chords have specific functions within a key and that their relationships to each other can be used to create cycles of tension and resolution that contribute to add movement to a piece of music. In this article, we will explore the key concepts that are essential to understand functional harmony and how these can be used in music, no matter what genre you are working in.
Understanding Key and Tonality
Before we can talk about functional harmony, we need to understand the concepts of key and tonality. A key is a set of notes that are used to create a piece of music. For instance, in the Key of C major, we get to play with the notes C, D, E, F, G, A and B, in no particular order.
These are the notes which we will ultimately use to build our chord structures. If we build triads or stack up thirds on top of each scale degree, we get the chords C, Dm, Em, F, G, Am, and Bdim – see scales harmonization. These chords are also often referred to by their roman numerals, with the I chord being C major, the ii chord being D minor, and so on.
On the other hand, tonality refers to the relationship between the different chords in a piece of music in reference to a tonal center. In tonal music, there is typically a “home” chord, or tonic, that serves as a point of stability and resolution.
Typically, In the key of C major, the tonic chord is C major. This means that, throughout the course of a piece of music, there will be a sense of tension and resolution as chords move away from and return to the tonic chord.
In short, key and tonality refer to the system of organization of music based on a tonic note or chord. This is the foundation to understand chord relationships based on tonal centers and also, while working in a specific key, we know which chords are going to work well together so you can start creating those chord progressions that move our listener through the different sections of our music.
But what is a chord progression?
Basically, it is simply a series of chords played in succession and it is the foundation of many popular songs. In functional harmony, or tonal music, the chord progression is based on a tonic chord, which is the central chord, or the chord that acts as the root of the progression.
The Tonic, Dominant, and Subdominant Chords
The three most important chords in the context of functional harmony are the tonic, subdominant, and dominant chords.
As seen, a tonic chord is the most stable and resolved chord in a key. It’s the home base, the place where our ears feel most at rest and where ultimately you return to. Keep in mind that you can choose whatever tonic center you wish and because of that, each tonic center can have its correspondent dominant and subdominant chords. One of the ways to tonicize a chord is through the use of secondary dominants.
The dominant chord creates the most tension and leads back to the tonic chord. It’s the chord that most strongly wants to resolve back to the tonic. For example, in the key of C major, our dominant chord is G.
The subdominant chord provides a sense of stability and contrast with the dominant chord. It’s less tense than the dominant chord, but still provides a sense of movement and direction as it helps to build up tension and movement towards the dominant chord and away from the tonic chord. In the key of C major, the subdominant chord would be F.
Using these three chords together is one of the easiest ways to create a functional chord progression. For example, a IV-V-I progression (in the key of C major, that’s F-G-C) is a classic chord progression or harmonic cadence that is ubiquitous in all kinds of music.
Other Chords in Functional Harmony
In addition to the tonic, dominant, and subdominant chords, there are other chords that are used in your chord progressions. These include the supertonic (2nd degree relative to the tonic), mediant (3rd degree), submediant (6th degree), and leading tone (7th degree) chords. These chords also play an important role in the cycle of tension and resolution as they contribute to add colour and interest to the harmonic progressions.
Tonality and Harmonic Cadences
Harmonic cadences are sequences of chords that create a sense of resolution and closure to the listener. It’s like a period at the end of a sentence as it marks the end of a musical idea or phrase – i.e. the end of the verse section. At the same time, they can be effectively used to confirm or even obscure the sense of tonic / tonality – an important concept for atonality and non-functional harmony chord sequences.
There are several types of cadences in Western music, but the most common that you can start experimenting with are the authentic cadence, the plagal cadence, and the deceptive cadence. Very briefly, the authentic cadence (V-I) is the strongest and most conclusive, the plagal cadence is less strong (IV-I) but still provides a sense of resolution, and the deceptive cadence (V-vi) creates a sense of surprise by defying the listener’s expectations.
Simply put, this is the process of changing keys within a piece of music, momentarily or definitely. It is often used to create a sense of contrast and to add complexity to the harmonic structure of a piece of music through contrast between harmonic materials of different tonalities.
As seen, we can use harmonic cadences and chords with certain functions in order to define the tonal center of a particular key. And we can use that same logic to navigate through different keys, where certain chords or cadences can assume certain functions in order to establish the new key.
By doing so, we are creating tension and excitement by introducing new harmonic information in the “old” key and when we resolve those tensions by confirming the new tonic or return to the previous one, we are participating in the movement of functional harmony, of creating cycles of tension and release by making use of chord functions.
The modulation processes may occur in a more subtle or jarring ways and it can be accomplished in a variety of ways – also see types of modulation.
Voice leading refers to how each individual note of a given chord progresses to the next. In functional harmony, voice leading is important because it can create smooth and natural-sounding chord progressions that help to reinforce the underlying harmonic structure of the music.
You may have chord tones that are common and thus they don’t change position from one chord to the next. This means that the more common notes you have between chords, the smoother the chord progression is going to sound, with less tension and contrast from one to another.
On the other hand, whenever notes need to move, they should do so using the smallest interval possible (i.e. half or whole step). Depending on the interval relationships involved in the movement of chord voices, you can create more or less tension – also see chord inversions.
Understanding these basic aspects of functional harmony is essential as they can help you to provide a sense of resolution, closure, tension, and surprise by making use of certain intervallic relationships and chord functions. This aspect of harmonic approach represents a major chunk of how Western tonal music is built and thought of.
All in all, by making use of these devices, you can create harmonic progressions that are more compelling and musically interesting. You can use cadences to structure your compositions and create a sense of forward motion or use them to manipulate the listener’s emotions, creating tension and release as the music unfolds. Also, by recognizing the different devices in other composer’s music, you will be able to gain a deeper understanding of how that piece is structured and how it creates its emotional impact.
And with all this in mind, I challenge you to consider other elements of music and how you could work with them in order to create tension and release cycles and using them to give structure to your music, confirm ideas, tonal centers, etc.
This means that it is time for you to apply these ideas to your music.
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