Written by Gary Ewer, from the “The Essential Secrets of Songwriting” website:
The word “modulation” is a music theorists’ term that means“to change key.” Changing key in the middle of a song is a great way to add interest and prolong a song. Done correctly, it can generate excitement and make a good song even better. Done poorly will sound forced and amateurish, so it’s important to think about why you’re wanting to change key, and then consider the best way to do it.
There are several reasons one might choose to change key:
- To intensify the energy-level of a song;
- Especially in duets, to put the song in an appropriate key for the singer;
- To create interest, especially in songs that feature a constantly recurring melody, such as in “AAA..” type songs
In other words, it’s important to remember that modulating should not be done haphazardly. There should be a reason for changing key. There are several ways to change key, and they all require you to think carefully about the chords you choose. Take a look at the following two examples, and you’ll probably find a method that will suit your situation:
1) The Half-Step Upward Method: This is likely one of the more common ways to modulate, and it’s the one whose prime reason is to increase energy. To put it simply, your basic chord progression ends, you then play a chord that is the dominant chord of the key you’re about to go to, then you repeat the progression a half-step higher.
Example: C F G C //Ab// Db Gb Ab Db
The Ab in the middle is the so-called “dominant chord” that sets your progression up for the new key.
2) The Miscellaneous Modulation (more than a half-step): This kind of progression can be somewhat unpredictable, so you really need to use your ears and decide if you like what you’re hearing. This is the one that you might choose for duets, to put the music in the right key for each singer. Consider that the dominant chord of the new key is going to be a safe way to change key no matter what key you’re going to.
In addition to using the new key’s dominant chord, you might also consider what is called “pivot chords.” These are chords that can exist in the old key as well as the key you’re going to. Here’s an example:
C Dm G Am Dm Gm7 C11 F
The progression moves from C major to F major. The pivot chords in this case are the Am and Dm chords; they can be seen to be the vi-chord and ii-chord from C major, but also as the iii-chord and vi-chord in the new key, F major. If this progression exists in order to allow the second singer in a duet to sing in a more comfortable key, you’ll need to consider a way to get from F major back to C major if the first singer needs to sing another verse. In that case, you could end the verse in F major, play a G major chord (i.e, the dominant chord of C major), and that sets you up nicely to get back to the key of C major.
Let me finish by giving you a few tips regarding changing key:
- Upward modulations are easier to manage than downward ones, because downward modulations can sap the energy of a song. Moving down by a 4th (key of C down to G, for example) can be seen also as moving up by a 5th (key of C up to G), so that’s fine. But moving down a semitone or a whole tone is tricky and should be avoided.
- If you’re not modulating up a semitione, then modulating to closely related keys (i.e., keys that use almost the same key signature… D to G for example) are easier on the listener’s ears. Moving from E major (4 sharps) to Bb major (2 flats) is weird, and hard to make work.
- Upward modulations should be accompanied by an intensifying of the lyric, singing style, or volume level.
- Save a modulation for later in a song. Changing key near the beginning will sound too abrupt.