Tuesday, July 5, 2016

The Art of Listening: Medium Length Pieces, Part 2

In my last post I talked about a ubiquitous ternary form, the minuet and trio, found usually as the third movement of string quartets and symphonies. I used this genre to introduce the idea of a contrasting section, which is usually called a "contrasting middle". This is one of the most fundamental structural ideas in music: present an idea, present a contrasting idea and then return to the first idea. There are some details that are important: the first idea or section has to have closure, usually a cadence. The second idea is often in a new key or new tempo or contrasts in other ways such as texture and melody with the first idea. Theorists distinguish between the small ternary and the large ternary, but for our purposes I don't think we need to worry too much about that. See William E. Caplin's Classical Form, p. 211 et seq. for a detailed discussion.

The ternary form with the contrasting middle is an easy form to hear the structure of and it became hugely popular during the 19th century. Mind you, it was also frequently used for slow movements during the Classical era. I want to pick out a couple of examples from the 19th century. Here is the Impromptu op. 90 no. 4 in A flat by Schubert played by Alfred Brendel:

That sparkling opening arpeggio is very distinctive which means that when we hear it return we become very aware of the ABA form. Here is how it looks:

This goes on until the 2:11 mark in the clip. The first section has been ended with a full cadence in A flat major, the home key. Then there are two measures of A flat with an added minor seventh. This is the enharmonic equivalent of G# major seventh which is the dominant of C# minor. Thus with the addition of one single note, that G flat (F# in the new key) Schubert modulates from A flat major to C# minor. Here is how the new section begins:

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This section contrasts with the first section in several ways. There is the key change, which is also a change of mode (from major to minor), but there is also a change in texture. The first section featured brilliant arpeggios in the upper register alternating with chords. Here we have a more typical melody on top with repeated chord accompaniment. The register is much lower and the melody has long notes instead of short ones. About the only thing that is common to the two sections is the meter of 3/4.

At the 4:52 mark in the clip, Schubert begins to transition back to the first section. He does this in two ways. First he prepares the change in key by moving to the dominant of the dominant in C# minor. This is D# major with a seventh. If we respell this as E flat major with a seventh, it is the dominant of the original key, A flat major. Again, a beautifully efficient modulation. While sitting on this chord he changes the key signature and the texture, returning to the high, sparkling arpeggios of the opening. This slips seamlessly into a repeat of the whole opening section. Finis. Here is how that transition looks:

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Now go have another listen to the performance, noticing the transitions between sections and how the mood changes.

In terms of what we might call the mood-schema of these pieces, typically the outer sections are more brilliant and energetic while the inner section takes us inward into a more reflective mood. This was why the form was particularly popular in the 19th century as this was the kind of effect composers were looking for.

I want to put up another example, from the end of the century. This is the Asturias (Leyenda) by Isaac Albéniz that is more often heard on guitar than piano these days. It offers a particularly stark contrast of tempo, texture and mood in the middle section. As it is so easy to hear, I won't put up musical examples. This performance is by John Williams on guitar:

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