Alphonse Nguyen

Modulation involves changing from one key to a different one (in the same piece). There are many reasons to modulate, which I won’t really go into, and there are different ways to do so, which you can check out here, but what I want to discuss today is how to make modulation sound good.

Let’s go over common chord modulation first, using Diabelli’s Sonatina, Op. 68, No. 2 (allegro moderato). With the first four bars of the exposition, he clearly establishes the key of G major. In the fifth bar, the E minor chord is the pivot chord that is diatonically common to the key of D major (E minor is the submediant/VI of G major but it is also the supertonic/II of D major), which he uses for his modulation. The following A major chord acts as the dominant of the new key and helps complete the transition.

Later on in the piece, Diabelli recapitulates to the original theme in G major. This time, the E minor chord remains as the submediant of G major, with the following A minor as the supertonic chord eventually going to the D major chord (which is the dominant/V of G major) to confirm the original key of G.

And that was one way of making modulation sound good and smooth. It worked well because the music didn’t sound out of place due to the reasons stated above (E minor chord going to either A major or A minor). Personally I think it’s amazing that a single note change can be that powerful (I’m talking about the C natural or C sharp in the A major/minor chords). Also, the modulation was effective because the melody remained almost the same in both cases, which helped in the transition by providing some familiarity and stability (with a twist).

I’d like to emphasize that last point and expand on it: when modulating, we tend to think about the chords, but we can’t forget about the melody. After all, the notes of the melody must fit with the notes of the chord’s harmony. Remember that the melody should still push forward (i.e. it has to make sense and it has to flow). As an example, first check out the opening of Mozart’s Piano Sonata No. 19 in Bb major:

At the end of the developmental section as he’s progressing to the recapitulation, see how he used the motives in the melody while modulating to ensure an effective transition:

The final point involves the execution of the modulation itself. Essentially, you can carry out fast or slow modulations, but they must have their place in the music. Sudden/quick modulations can be a good tool, as it forces the listener to become aware of what just happened. However, they tend to be overused in modern/pop music as the chorus is often repeated almost immediately in a new key. Myself, I prefer gradual/subtle modulations, the kind where you don’t even realize it’s happening.

And there you go, have fun!

Check out other composition articles here.