Structural Considerations for Music

In the past century or so, music has followed the same trend as art in general: its definition has been greatly expanded, and somewhat muddled. Nowadays, the variety of things appearing under the name "music" has grown to include many things which would not have been considered music in centuries past: atonal music, Musique Concrète, noise music, and even hip-hop. What all of these forms of music have in common is that they are made up of sounds: that is to say, they are sequences of acoustical events organized in time. However, many things which are not music also fit this definition: a conversation, for instance, is also a sequence of acoustical events organized in time. Ultimately, it all comes down to a question of intent, and creators of music arguably have a particular set of common goals in mind when they set out to create their music.

Stated a different way, all music follows certain guiding principles which ultimately define it as music. These are the principles of tension and release, and similarity and variety. These principles apply to the creation of any sort of music: classical music, popular music, noise music, dance music, et cetera. They also apply no matter what the method of creation: they apply not only to composing music, but also to improvisation, DJing, et cetera. This article will primarily examine these concepts in the context of classical composition, but they can be readily generalized to these other forms of music.

Tension and Release

We will first examine tension and release, which is one of the central ideas that makes music compelling. Tension and release, also known as "movement," is essentially the process of creating expectations within the listener, delaying their fulfillment (tension), and then fulfilling them (release). Tension can be stretched out to varying lengths, with correspondingly varying levels of excitement created: however, tension that is drawn out too long can frustrate the listener, destroying the effect. In a piece of substantial length, there will be many levels of tension and release, and the tension and release will be created by many methods. Here are some commonly employed methods of creating tension and release:

• Melody: Movement upwards creates tension; movement downwards releases it.
• Harmony: Chords other than the tonic, particularly the dominant, create tension, and the tonic releases it. On another level, modulation away from the tonic creates tension, and modulation to the tonic releases it. (Of course, these comments only apply for classical harmony.)
• Counterpoint: Thickening of contrapuntal texture creates tension, and simplifying of texture releases it.
• Rhythm: Upbeats create tension; downbeats release it.

All of these may be points of contention: it is possible to imagine many scenarios in which these elements are not used in this way. These principles are therefore merely heuristics, and not laws. Furthermore, this is not a comprehensive list, representing only a subset of the techniques used in a particular genre of music (the common practice style of classical music).

Contrast and Similarity

Tension and release is not the only thing necessary to make music interesting. Consider a piece of music which consists of a single melody, over a harmonic progression, repeated ad infinitum. It has tension and release, provided by the melody and harmony, and it will be interesting for the first two or three repetitions, but then it will become boring.

A well-made piece of music of any nontrivial length will consist of multiple sections which contrast each other. The longer the piece, the more contrast required. The contrast can be created in a variety of ways: by modulating to different keys, using different melodies, rhythms, and chords, and by using different orchestration, for instance (other examples will apply in other genres of music). It is important to realize that, in a large piece, there will be many levels of such divisions: a symphony will feature sections in different tempi and different moods, and each of these sections will be further divided into multiple levels of sections distinguished by key, orchestration, mood, rhythm, et cetera.

It is also important to recognize that there are many shadings of similarity between different sections. Two variations on the same theme will be more similar than one of those variations and a variation on a completely different theme. The composer of a piece of substantial length will have to create sections with many different levels of similarity.

The goal of contrast is to prevent boredom. However, contrast cannot be used indiscriminately: a piece of music consisting a series of unrelated sections, smoothly integrated, may be somewhat enjoyable, but it will not be as rewarding as it could be. Having sections that are similar to each other is also necessary. Similarity between sections exploits the memory: the listener remembers hearing the material previously, and their experience is amplified. This principle is, of course, at odds with the avoidance of boredom due to too much similarity. The goal of the composer should be to balance these two conflicting pulls.

These principles of contrast and similarity can be applied to understand the actual practice of composers in terms of musical structure. All of the standard sectional forms (binary, ternary, arch, rondo, etc.), as well as the verse-chorus form of popular music, the variation forms such as passacaglia and chaconne, and the developmental forms such as fugue and sonata, can be readily justified by how they serve the purpose of balancing contrast and similarity. This is left as an exercise to the reader.

By Nick Thomas.