Inventions and Fugues
Inventions and fugues share many features, but the differences are very easy to recognize once you know what you are looking for.
To begin with, they are both contrapuntal polyphonic works. However, the main differences are their harmonic forms and the number of voices – 2 to 3 in inventions, and 3 to 5 in fugues.
Inventions and fugues both embody the idea of Fortspinnung – a term used to identify the development of a musical motif that seems to cause it to spin out of control. The motif becomes an entire musical structure through the use of simple repetitions, intervallic changes, or sequences.
Inventions
Inventions were common in the Baroque period. This type of music was often a short contrapuntal piece built upon a simple motif that was played between two or three voices.
This video by ATonalHits about inventions discusses Bach’s inventions and his reasons for composing them.
Fugues
Fugues feature a clear solo voice that announces the subject, exposing us to the motif – the subject -that will be developed as the piece continues. This is aptly called the exposition. The subject is then repeated a 5th above, or 4th below – the answer.
The answer is considered a real answer if it appears as an exact copy of the subject, with identical intervals to the first statement. If the intervals are altered to maintain the key it is a tonal answer.
The subject appears in all voices in the home key before we arrive at the middle section where the motif could be altered using diminution augmentation, or inversion among other techniques. The subject also modulates in the middle section.
In the final section, the subject is restated in its original form, in the original key again.
Here is a complete fugue example by Ben Dunnett from Music Theory Academy.
He labeled the main sections and highlighted the 3 voices in different colors so it is easier to identify the different voices and see how they all work together.
Simple Imitative Form in Practice
Our assignment this week was to compose a short piece based on imitative form.
Below is a video of Daniel Saunders and I playing his piece, “Composing A Round,” to demonstrate how it would sound. The piece was written for 5 voices. You can find the full score here on his website.
I also did a short piece, “Round 1.” It is a short round. I wrote it out so you can follow along and see how the harmony changes as voices are added.
Round-1