Often in our Sunday worship, we’ll have a setlist of songs that are in unrelated or different keys to each other. Part of the musicians role (particularly and most importantly the keyboardists role) is to change keys between these songs (modulate) so that the transitions and dead time between songs are as seamless and smooth as possible.
It’s worth diving a bit into some basic musical theory, as this will help us to understand the principles and application of switching between keys. This is by no means advanced musical theory, but does take a bit of understanding and practice to really get right.
Firstly, every key has a scale degree. Their names are:
Each number refers to the note in the scale of the key. For instance, in the key of F major, the tonic (I) is F, the subdominant (IV) is Bb and the dominant (V) is C.
The aim of a dominant chord is to provide what’s called a cadence. A cadence is a way for the song to head back to the home key or the tonic. We hear this V to I progression in pretty much any piece of music you could think of. This structure is important in our understanding of how key changes work. If we look at the key of F major as our example, we can see three main ways to achieve this.
This simply means to finish the song and go straight into the new key. The benefit of this is that there’s very little preparation required, and it’s how a majority of Corps and churches will handle their transitions.
A downside to this method is that it can take a few bars for the congregation to adjust to the key. It also means that your singers will have to be confident in the transition and be able to carry the melody through to the new key.
This method is slightly more subtle in its approach. It requires the player to find a common note that is shared between both keys, and to use it as a “bridge” to link the keys. It may or may not be the melody note, but it needs to be a common note.
For instance, moving from the key of F to Db allows us to use F as a bridging note, as it’s a shared note (being the tonic (I) of F and the mediant (III) of Db). By repeating this note, you can change the key quite easily.
It does require that the singers are again able to carry the melody through, and also requires that you understand which notes relate to the key you are trying to move into.
The third method is the most versatile but requires the most understanding to get right. Fortunately, it’s rather simple once you get the hang of it, and can make transitioning between the most awkward keys simple. The most important part involves playing a V to I progression in the bass, with a IV to I progression in the right hand providing a different cadence.
Lets look at an example:
If we want to move from F to G maj, we need to identify the dominant note (V) of G — which is D. Our V to I cadence therefore is D to G and will be played with the left hand, the bass.
The right hand will play a IV to I (or C to G) cadence.
When we’re finished, our pivot chord will look like this: a C chord with a D in the bass. This leads nicely into the tonic of the new key.
If this is starting to make your head swim, don’t fret! Just look at it on your keyboard and it’ll make visualising the distances between the keys easy. Try playing the previous example and it should click after a few tries.
Moving through keys is a valuable skill for any musician, so it’s worth investing some time in getting it right. It’s worth noting that it’s much easier to move up through keys than down, though you can experiment with the pivot chord to see what kind of results you get.