Grade Six Music Theory Composition; Lesson 2 - Motifs & Melodic Sequences

Motifs

A motif is a short, memorable unit of music. A phrase can be made up of motifs which could be as short as just one or two beats’ worth of music. Typically, motifs are re-used throughout a piece to give a sense of continuity to the music. Although not all pieces of music contain motifs, many many do, and they are a useful weapon to have in your arsenal of compositional techniques! Probably the most famous motif in classical music is the four-note sequence from Beethoven’s Fifth Symphony:
 

The motif is repeated many times throughout the first movement. Sometimes the pitch is altered, sometimes it is sped up, but it keeps its character. The character of a motif is usually defined by its rhythm.

When you develop the opening material given in the Grade Six music theory exam, you will need to decide which element is interesting enough or promising enough to work as a motif. You then need to make sure the motif reappears in the rest of the piece enough times for it to become a “characteristic” of your composition.

Examples

Here are some examples of motifs in action. Play them through and notice how the motifs are altered in simple ways in order to give a feeling of continuity with variety.

Our first example comes from the Waltz in A flat by Brahms, Op.39 no.15. The motif is a dotted crotchet followed by three quavers, with the following “rough” melodic shape:

All the notes are taken from the chords which make up the underlying harmony. The melodic shape of the motif is pretty constant too – the first two quavers are lower in pitch than the crotchet, and are repeated, and the final quaver is the same pitch as the crotchet (or close enough).

Here are the first eight bars. (Try to listen to the whole piece – you will notice the motif occurs throughout.) The motif occurs 5 times here, and then a final time in the 8th bar as a linking sequence into the next phrase. (Note – you only need to write a single line of melody for the Grade Six music theory exam.)

Our second example is from Rachmaninov’s Prelude for Piano Op.23 no.5. The motif is a rhythmic unit: quaver – semiquaver – semiquaver – quaver. It is usually made up of the notes of the underlying chord. The first quaver is stressed and forms part of the melody. The other three notes are repeated and are of a higher pitch and form part of the accompaniment. Here are the first 5 and a bit bars:

Melodic Sequences

A melodic sequence is a series of notes which is repeated but with a different starting note. The basic intervals between consecutive notes are kept the same. Usually all the notes are taken from the scale which forms the key of the piece, and therefore they aren’t “chromatically altered” in any way – which means we don’t see any sharps or flats added. Sometimes however, chromatic alteration does take place. We’ll take a look at both types of sequence.

Here’s a simple melodic fragment of five notes:

The melodic interval between notes 1 and 2 is a second. Actually it’s a major second, but we don’t need to worry about that too much right now. We can write out all the intervals between consecutive notes: 1-2=2nd ; 2-3=3rd ; 3-4=2nd ; 4-5=3rd . Next we will change the starting note – let’s pick G. We then write out the melody again, based on those intervals, but still keeping to the notes available in F major:

This is a “diatonic” melodic sequence. This means that the notes are chosen to fit in with the scale, rather than to be an exact match of intervals. Why so? When we examine the “quality” (e.g. major/minor…) of the intervals, we’ll see that they are different.

The interval quality has changed from notes 3-5. This gives the sequence a slightly different character to the original, but of course in many respects it is the same. This simple modification makes a new fragment of music which has both continuity with and variety from the original material.

What happens if we try to match up the intervals exactly? We get a “chromatic” sequence instead of a “diatonic” one. We need to add in some accidentals in order to preserve the interval “quality”, and these accidentals will usually have the effect of making the music change key. This is also known as “modulation”. Here’s what happens when we match the intervals exactly:

The only change we needed to make was to sharpen the Bb up to a B natural. But because B natural doesn’t occur in the scale of F major, we sense that the music is changing key. We feel as though G is the new tonic, and that therefore the music has modulated to G major.

Play these two 4-bar extracts, and notice how the first seems to stay firmly rooted in F major, but the second appears to modulate to G major:

Hopefully by now you’ve got an impression of how useful melodic sequences are in composition. Sequences are hugely powerful devices when it comes to developing musical ideas. They allow you to easily write connected but contrasting fragments of music, and with a simple tweak here or there they can be used to make your music change key in the bat of an eye! You will notice that diatonic sequences are a lot more common than chromatic ones, as you would expect.

Examples

We will finish this unit with an example of a diatonic and a chromatic sequence. Whenever you are playing any music at all however, you should take a moment to stop and look carefully at what has been written, and see if you can spot any sequences in action. See if you can work out whether they are diatonic or not, and if they are chromatic, what key do they lead to?

Our first example is from the opening of Mozart’s Piano Sonata no.14 K457 in C minor. It is a diatonic sequence, played first from the tonic and then from the dominant note (G in C minor). Other minor changes (marked by arrows in the extract) take place along the way.

Chromatic sequences are a lot less common than diatonic ones. However, you probably know this famous example, from the song “Do – Re – Mi” from the musical “The Sound of Music”.

• The sequence consists of a 2-bar phrase.
• It starts with the first six notes of the C major scale, ending with a major 2nd.
• The next two bars form an exact chromatic sequence – the starting note is one tone higher and the six notes are from the scale of D major, with the F sharpened with an accidental.
• The third instance of the sequence is almost the same (up a tone, E major scale for the first five notes), but it ends with a minor 2nd interval, so technically this one is a diatonic sequence.