Composing Two-Part Inventions

Using contrapuntal techniques such as imitation, inversion, augmentation and diminution allows you to make a lot out of very little. The added benefit I've noticed is that reusing material in these ways keeps it familiar though interesting for the listener. My general strategy when undertaking these exercises is first to think of a short, catchy motif. This is a frequently found in Bach's inventions and fugues, and as well as providing a good tune a memorable melody is easier to pick out in a multiple-voice texture. I then resolved to manipulate this material in the aforementioned ways, keeping a close eye on the musical result, then adding suitable dynamic and expression markings to finish. I've also taken the opportunity in these inventions to try out my knowledge of modulation. This is not required at this stage of the course but I wanted to try it nonetheless.

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In my first attempt at composing a two-part invention, I created a simple, catchy, syncopated five-note motif to form the basis of the piece. This is then manipulated as follows:

Key: C Major

Bar 1 - Subject stated in upper voice (flute).
Bar 2 - Subject imitated down an octave in the lower voice (clarinet). A new four-note idea is presented in the upper voice.
Bar 3 - Subject is stated a fifth higher than bar 1 by upper voice. Lower voice plays flute's four-note idea from bar 2.
Bar 4 - Upper voice plays descending sequence based on last four notes of subject. Lower voice plays subject in inversion.
Bar 5 - Upper voice continues sequence, lower voice repeats the inverted subject, but an octave lower than in bar 4.

Key: A Minor (relative minor)

Bars 6-7 - Lower voice begins an upwards sequence like that played by the upper voice in bars 3-4. Upper voice plays the subject but this time augmented.
Bar 8 - The Lower voice plays a slightly modified version of the augmented subject. The upper voice plays the original subject but in the tonic of the new key.
Bar 9 - Both voices play a modified subject, in contrary motion.
Bar 10 - Both voices end on the tonic of the new key.

The modulation was to the relative minor key, using a pivot chord VI/I, then a perfect cadence V-I in the new key.

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In this second invention I tried to convey a contrasting character, this time also utilising tuned percussion in the form of timpani. Again I created a short motif, in this case a descending six-note idea followed by a one-beat rest.

Key: C-Sharp Minor

Bar 1 - Upper voice (alto saxophone) plays the subject.
Bar 2 - Lower voice (timpani) imitates the subject, an octave lower. Upper voice introduces new material, an ascending articulated arpeggio.
Bar 3 - Lower voice imitates the arpeggio idea, two octaves lower. The staccatos become accents due to the timpani not being articulate enough to mirror the same idea from the saxophone. Upper voice plays the subject a fifth higher than the original.
Bar 4 - Upper voice plays an ascending sequence (descending at end of bar) based on the same rhythmic idea in the subject. Lower voice plays an augmented version of the middle two beats of the subject.
Bar 5 - Upper voice plays the subject in inversion. Lower voice plays the arpeggio material in diminution and inversion.

Key: E Major (relative major)

Bar 6 - Upper voice plays arpeggio idea. Lower voice imitates the inverted subject.
Bar 7 - Upper voice plays inverted subject. Lower voice plays the subject in diminution and inversion.

Key: C-Sharp Minor (original key, relative minor)

Bar 8 - Upper voice repeats inverted subject. Lower voice plays the subject in retrograde (backwards).
Bar 9 - Lower voice plays ascending arpeggio idea in diminution. Upper voice plays a short descending sequence based on first four notes of subject.
Bar 10 - Upper voice first plays ascending arpeggio idea in diminution, Then a slightly modified subject in diminution. Lower voice plays subject in diminution and inversion, then an extract of the subject in retrograde.
Bar 11 - Upper voice ends with a crotchet on the tonic. Lower voice also ends on a crotchet on the tonic, but a half-beat later than the upper voice for effect.

Reflection

This was a very interesting first foray into writing an invention. Using the array of contrapuntal techniques available you are able to create interesting swathes of music with very little starting material. I think this fits well with my own creative process - I find thinking of an interesting motif quite difficult, but once I have one I am quite comfortable with manipulating it to create further material, my techniques for which have been expanded in this exercise.

In hindsight one area that I think I could have explored more of is the use of syncopation, suspensions etc.; techniques to allow one voice to continue across a bar line while the other doesn't. Some of Bach's inventions feature them intensely, and others not at all. This is something I can consider and develop in the forthcoming assignment.