Modulations are not stipulated in the ABRSM Grade 8 Composition question, but they are strongly recommended. You are unlikely to get a high mark in the exam if you do not modulate. I would recommend writing two to three substantial modulations (as opposed to brief “passing through” type key changes. Aim to balance the sections in each key, for example bars 1-4 in key 1, bars 5-8 in key 2, bars 9-12 in keys 3 and 1. Avoid unbalanced modulations, for example bars 1-8 in key 1, bars 9-12 in keys 2, 3 and 1.
Keys that are closely related to each other are easier to work with.:
- the relative major or minor
- the dominant
- the subdominant
In the key of C for example, the most closely related keys are A minor, G major and F major.
You can also modulate to the closely related keys of the closely related keys, as illustrated below. The centre of the diagram shows the “home key”. The next layer of keys are the closely related keys, and the outer layer are the keys related to the middle layer.
A good plan is for your first modulation to be the most distant one from the home key (i.e. one from the outer edge of the diagram). After this first “spring away”, you move back to the home key with a series of V7-I progressions. For example:
Home key (C) > modulate to Em (most distant)> modulate to G major (with D7-G) > modulate back to C (G7-C).
The Supertonic Modulation
One very common and easy to use modulation technique is the supertonic modulation. To do this, move from the tonic to the supertonic major key, then to the dominant major key, then back to the tonic. The supertonic and dominant chords can also take an added 7th for added interest.
E.g. C major > D major > G major > C major
or A minor > B major > E major > A minor.
How to Modulate
Recommended method for effective modulation
The easiest way to modulate is via a pivot chord (a chord which exists in both the old and new keys). You can modulate without a pivot, but they often help. V7 usually makes a stronger modulation than just V. Chromatic chords such as N6 can also be used as pivots.
The progression of chords should be this:
Pivot chord – V7 (new key) – I (or i) (new key).
These chords should occur one after the other, usually without any other chords occurring between them. Ideally you would place the new tonic chord on a strong beat.
For example, to modulate from C major to F major:
D minor (pivot) > C7 (V7 in F major) > F (I in F major)
To modulate from C major to A minor:
D minor (pivot) > E7 (V7 in A minor) > A minor (i in A minor)
A unique note is one which only exists in the new key, and not in the old. In order to write a convincing modulation, you will need to make sure you use the notes which are unique to the new key in your melody, otherwise the result will be an ambiguous harmony which is neither one thing nor the other.
Let’s take a modulation from C major to A minor as an example. We could use a pivot chord of D minor, which is chord ii in C major and iv in A minor, to make the following progression:
ii/iv (Dm) – V7 (E7) – i (Am)
The note which is unique to A minor (i.e. not in C major) is G#, so we will need to ensure that the melody contains a G# at the point when the E7 chord is intended. If we used only E and D at that point, the ear would not be convinced that the intended harmony is E7, and would probably infer that the key was still C major.
Another way to modulate is to use a real sequence. Copy part of the melody onto a different starting note and add accidentals, so that the interval quality (e.g. major/perfect etc.) remains identical to the original.