16a Lesson - Defining modulation

What is a modulation?

A modulation occurs in a tonal piece of music when the tonic pitch changes. Most musicians understand this concept on an intuitive level, but there are a few common misconceptions.

• Modulations are sometimes referred to as a “key change”, but the key signature does not necessarily need to be altered for a modulation to occur. Repeated accidentals are a more consistent hint that a modulation may have happened.
• The term “key change” also does not account for the fact that a shift between the parallel major and minor modes (e.g. C major to C minor) is not a modulation but do have different key signatures. This is a shift in mode – not a modulation – because the tonic does not change.

Key relationships

In our first studies of modulation, we will look at modulations between closely-related keys. Closely-related keys are keys that are within one accidental of each other. Each key has five closely-related keys. To practice, write the closely-related keys for:

• C major
• A minor
• C-sharp major
• E-flat minor

When determining closely-related keys, it is helpful to think of the relative major and minor keys as well as their closely-related keys, but the parallel major or minor is always a distantly-related key.

Conclusions

Any key will have five closely related keys: two of the same mode, and three of the opposite mode. You can find these quickly by finding the relative major/minor key of the starting key, and then adding one sharp and one flat to both of these keys. For example, C major has a relative minor of A minor. If you add a sharp to both of those key signatures you get G major and E minor. If you add a flat to both of those key signatures, you get F major and D minor. The chart below shows the closely related keys for the four examples from above.

Key	Closely related major keys	Closely related minor keys
C major	G major, F major	A minor, E minor, D minor
A minor	C major, G major, F major	E minor, D minor
C-sharp minor	E major, B major, A major	G-sharp minor, F-sharp minor
E-flat minor	G-flat major, C-flat major, D-flat major	A-flat minor, B-flat minor

Differentiating modulation and tonicization?

The biggest difficulty regarding modulation is differentiating between modulation and tonicization. Some modulations will be obvious, but others can be contentious. Because a modulation is defined by a change in the tonic, it is necessary to consider how music establishes tonic in the listener’s ear. In earlier units, we discussed the importance of phrasing and cadences, but the following exercise will further clarify their importance.

On a scratch piece of paper, do the following for each of the examples below:

1. Listen to the entire excerpt, and at the end, sing the tonic (do). Use your ear-training while looking at the final chord to determine which pitch you sang. Write this on your scratch paper.
   • If you are struggling to identify your tonic, try singing along with the soprano line. Once you arrive at the cadence, sing up and down the scale until you arrive at something that feels completely stable. You should then be able to count the scale degrees through which you must move to arrive at do.
2. Listen to the excerpt again, but pause each time you come to the end of a phrase. Most of the phrases in the excerpts below are marked by fermatas, but you should be able to identify cadences as aurally as well. Each time you pause the excerpt, sing your current do. This may require you to find a pitch that is not present in the chord because some of the phrase endings do not have do in the chord. (i.e. if there is a half cadence)
3. Compare your tonics from each phrase. Does it change throughout the excerpt? If so, you should be able to pinpoint the phrase in which it modulated.

Some of these examples modulate, yet some are only tonicizations. What do all of the modulations have in common? What about the tonicizations? How does this change your perception of modulation? Is there some commonality among the modulations that will help you visually identify a modulation if you do not have access to playback or a recording?

Above all else, you will notice that we are not beginning our discussion of modulation by looking at this from a theoretical perspective. Modulation is determined by the listener, and you will often find yourself disagreeing with others. In many cases, modulation is subjective, but this becomes more concrete with experience.

After you have finished listening to each of these and feel that you have an opinion on whether each modulated, go on to the next unit to begin studying the most common methods that composers use to modulate.