Key choice and Modulation
Depending on what kind of music you listen to, modulation can be either rare or rife. In pop music, modulation is usually reserved for a single important moment in a song, while in classical music, the modulations can be hard to keep track of because they are so frequent and often also subtle.
Today, let's take a look at what modulation can offer you as a composer.
Before we start, you might be interested in reading up on what modulation is. In that case, I recommend heading over to 12tone's Youtube channel and watch his video on modulation. For further reading, I also recommend the articles on Toby Rush's website.
1. Harmonic interest
Modulation creates a sense of contrast. When we are exposed to the same key for a prolonged period of time, the initial impression of color slowly fades. We become used to it.
By introducing a new key, the colors are reinvigorated.
The strength of the contrast is controlled by how distant the new key is, how many notes it differs from the old one and the type of transition we use. A sudden change of key will be surprising, while a gradual change of key will generally be gentler.
In Flying Clouds, Drifting Haze, Hayato Asano uses a direct modulation to create a burst of musical color. The new key is only a semitone away, but with 5 out of the 7 original notes in the scale being changed out, it has a strong sense of novelty. Jump to 0:34 in the video to hear it.
In this tweet, you can observe the composer Hayato Asano test out different key changes as he looks for one that will fit the transition the best: アサノハヤト / Hayato Asano on Twitter: "キーを決めあぐねておる… "
Here's another semitone modulation from Richard Wagner's opera Lohengrin. This time however, the modulation is gradual. Still, he makes a pretty strong point out of it by transforming the tonic chord Eb/G to Ebm/Gb. He then tonicizes Db major, but quickly repeats the process and turns the tonic chord into C#m/G# (enharmonically equivalent to Dbm/Ab), and from here: E/B, B7 and then finally landing softly in E major. Jump to 3:46 to hear the passage. You can also follow along from the 10th bar on page 2 in this score from IMSLP.
2. Timbral qualities
Instruments have different registers, that in turn have different timbral qualities.
A flute has a duller, hollower sound to it when it plays in the bottom octave of its range, while above this it starts sounding more brilliant and piercing. Similarily, a bassoon is powerful in its lower register, while becoming gradually more hoarse and frail as it climbs upwards.
It may happen that a melody you planned to give to a certain instrument doesn't really fit into the sweet spot where the timbral qualities helps give it the personality you want.
By modulating to a different key however, we can open up registers that are more advantageous to the instruments we want to use.
This flute melody sounds nice, but it isn't quite the personality we were going for. It's too bright. We could try transposing it down an octave, but that would make the melody go outside the range of the flute, making it impossible to play. But maybe we could transpose a fifth down to the subdominant key instead?
Now it sounds more secretive and airy. Exactly what we wanted!
There's also something to be said for how an instrument reacts to certain keys. A violin playing a melody in D major will sound brilliant and bright, taking advantage of the resonance from the notes the strings are tuned to.
Similarily, the strings of a harp are most relaxed and resonant in the home key of Cb major. It may be a good idea to modulate to Cb major when the harp solo you've been planning is coming up. Indeed, the harp part in the flute melody above would probably have sounded more relaxed in a flatter key.
3. Technical practicality
When it comes to keys, some are more comfortable to play and sing in than others.
We talked about how the violin sounds good in D major, however it's also the case that it's a very comfortable key to play in from a technical perspective: It will be easier to play in tune, the open strings give a sense of security, and because violinists are often more experienced with that key.
Similarily, brass instruments are usually more comfortable in flat keys. It's also common for vocalists to transpose songs to the key they're most comfortable in.
To give the musicians the best experience possible playing your music, to cut down on rehearsal time, as well as lowering the risk of sour notes during performance, it's worth taking the playability of the key into consideration.
Since the optimal key may change depending on what's going on in the arrangement at a given time, you can modulate accordingly.
The less time and mental energy spent rehearsing technique, the more can be devoted to making the performance as musically satisfying as possible.
For more information, I recommend checking out Orchestration Online, a great resource on orchestration:
4. Musical punctuation
Keys can help give each section in your music a distinct flavor. Modulating to another key for a new section can therefore work as a road sign for the listener, helping them make sense of the piece on a larger scale.
In Voi Voi by Nora Brockstedt, the verse is written in major, while the chorus modulates to the parallel minor key.
The contrast from the modulation strengthens the feeling that the chorus is something seperate from the verse.
In the classical sonata form, the piece first starts in one key, secondly moves away to distant keys, and finally returns back to the home key for the ending.
The contrast between the sections that are grounded in the home key on one hand, and the sections where the piece is moving through keys on the other helps clarify these three phases.
To learn more, check out my previous post about musical punctuation.
In Motivic Development - Part 2 I wrote about how motifs and themes can take on symbolic properties by presenting them together with a character or an idea - what we call leitmotifs.
We can do the same with keys. However, the effect will be more subtle. A listener will not pick up on this consciously, the key can however help set a certain mood with its characteristic color relative to the other keys that are being used.
The song Stardust by Sound Horizon opens with an intro in A major, but the signature riff of the song that follows is presented in B minor. The song then continues in A major, takes a few detours to other keys, and returns to A major for the reprise of the chrous. After the final chorus however, the song launches into a finale in B minor. The B minor riff then takes it over and finishes the song.
Looking at the keys alone, a story is implied here: The first occurence of B minor foreshadows that something sinister is bubbling under the A major surface, but it will remain hidden for now. By the end of the song however, B minor rises fully to the surface and takes over. The song that started in A major ends in B minor, representing and subtly underlining a change that has taken place.
This echoes the story of the song.
With all these great reasons for modulating, one would think that it would be a more widespread practice. The downside to all the advantages is that music that modulates a lot can be difficult to perform. It can also be information overload for a listener.
When modulating, it's often the case that several of the factors that we outlined are at play at the same time.
On one hand, it's good compositional craft to kill two birds with one stone: Imagine creating a purposeful color change while at the same time establishing the optimal key for an upcoming solo.
On the other hand, some of the factors may unintentionally come into play without the composer being aware of it: Modulating to prepare a desired register, but forgetting that a sudden color change isn't necessarily tasteful in this part of the song.
Therefore, weighing the pros against the cons is important to achieve the effects you desire in your music.
With this, I hope you feel inspired to explore the possibilities of modulation further. Feel free to subscribe in the form at the top of the page to get an email notification whenever the site is updated with content. Please share your thoughts with us in the comment section below as well. Until next time!