In Western music, the three tonal functions are: tonic (‘T’), predominant or subdominant (‘S’) and dominant (‘D’).
Chords with tonic function transmit a sense of peace and tranquility. They create stability, while predominant sound a bit unstable. Predominant chords are often used to indicate movement away from the tonic center or root, towards a dominant chord. Dominant chords create tension or harmonic dissonance, which wants to resolve.
Typically, tonic and predominant chords can be followed by any diatonic chord, irrespective of harmonic function. Dominant chords, however, usually resolve back to the tonic chord or root. This is where tension is resolved.
Harmonic function of chords
The table above shows which chords have tonic, predominant and dominant function in major and minor keys. This will allow us to take a deeper look at chord progressions. Let’s take a ‘I – ii – IV – V’ chord progression in the key of C major, which consists of the following chords: 'C – Dm – F – G'. The table shows us how a ‘I – ii – IV – V’ progression in the key of C major is structured:
In this example, you can see that the chords are used to slowly create tension, which is eventually resolved as the chord progression leads back to the tonic chord ('C').
Harmonic function is of great use when telling a story through music. You can experiment with creating and resolving tension in a chord progression to make a song more interesting. Feel free to ask any questions in the comments below. And if you are ready to deepen your understanding of music theory – be sure to take a look at the Wheel of Fifths Songwriting Tool, available for purchase globally in our shop.