Small ternary form is a great way for you to create a three part piece. It follows a simple structure, A-B-A’, but built into it is a set of very useful techniques that you can use to add logic and interest to your themes.

In this article, you’ll learn about some great techniques for creating an interesting and contrasting B section, called the contrasting middle, and how you can add or remove material when you bring back your A prime section, called the recapitulation. If you haven’t covered the sentence and period yet, I would recommend starting with those articles.

Themes as Musical Archetypes

So let’s talk about the small ternary form and small binary form. These forms, along with the sentence and period, are really the basis for most classical themes. If you’re interested in learning how to compose using these forms, I have an in depth course that covers all of these theme types. Check out The Fundamentals of Musical Composition.

There are additional hybrid themes, which I explore in my course Composing Music in Sonata Form.

But let me be clear, I am not saying that most music fits these forms exactly. Music has a way of not fitting into the cookie-cutter examples. Instead we need to look at them as prototypes, or even better, archetypes. They are kind of like DNA. DNA can have millions of different combinations, and create infinite variety. But DNA only really contains four molecules, just rearranged over and over again.

Small Ternary

We start our conversation off with small ternary form. The small ternary form is, as you would guess from the name, basically a three part theme. It is commonly written as A-B-A’. It has three formal functions.

1. Exposition (A)
2. Contrasting Middle (B)
3. Recapitulation (A’)

This mirrors another, another large form, the Sonata Form. But the Sonata Form is a little too big to cover today, so I’ll save it for another post.

Let’s listen to a complete small ternary form.

The Exposition

The exposition in small ternary form is normally made up of a sentence or period, as discussed in the previous posts. Normally in an exposition, these two theme types appear in their basic form, or a hybrid form (mixing elements from sentences and periods). When they are 8 bars, and contain all of their basic formal functions, they are known as tight-knit themes.

The Contrasting Middle

The contrasting middle section in small ternary form gets its contrast mostly by harmonic means. The goal for the contrasting middle section is almost always dominant harmony (V). The contrasting middle has a few different charcteristics from the expositions as well:

1. Tends to be much looser in organization
2. Creates instability (mostly harmonic instability)
3. Frequently changes texture

Tight-Knit vs. Loose Organization

Let me talk a moment about tight-knit themes and loose themes. These are terms, once again from Classical Form, by William Caplin. I think they are excellent ways of thinking about how to use these forms for real composing.

Tight-Knit Form

Tight-knit usually refers to the basic theme types, the sentence and period. They are both 8 bars, and can be explained relatively easily. They also have a number of hybrids, mixing the parts of both periods and sentences together.

Hybrids

1. Compound Basic Idea (an antecedent without a cadence) + Continuation
2. Antecedent + Continuation
3. Antecedent + Expanded Cadential (cadential takes up the entire continuation)
4. Compound Basic Idea + Consequent

Loose Form

In comparison with tight-knit themes, loose themes use certain devices to add material and expand the 8 bar themes beyond their usual scope:

1. Extension – Adding on extra material. This is usually accomplished through further fragmentation of ideas. It is also very common in cadences.
2. Expansion – “Internally lengthening components” of a formal function from there typcial length in a tight-knit theme.
3. Interpolation – Adding on extra material, that has no other formal function.

Recapitulation

The recapitulation is the final part of the small ternary form. This is commonly a tight-knit theme. It is called the recapitulation because it brings back the material from the exposition. Very frequently it gets rid of unnecessary material as well. What is unnecessary? Let’s look at a period for example.

The period has an antecedent phrase, consisting of a basic idea, and a contrasting Idea with a weak cadence.

It also has a consequent phrase, consisting of a repeat of the basic idea, and a new contrasting idea with a strong cadence.

Just looking at the words above, you can clearly see what is “unnecessary.” It is material that is functionally redundant.

1. Basic idea
2. Contrasting Idea with a weak cadence,
3. Repeat of basic idea
4. New contrasting idea with a strong cadence.

A period, with the functionally redundant material taken out, is essentially a consequent phrase.

This allows you to take a simple 8 bar theme, and turn it into a 4 bar theme. But it doesn’t just stop there.

You can just as easily expand it with the devices mentioned earlier, as well as a codetta, which is kind of like multiple cadences after each other, helping to dissipate the built up tension during the phrase. I’ll be talking about the codetta, and other framing functions, as well as interthematic functions in a few weeks, when we look at the first movement of the Symphony (no, I haven’t forgotten what this is all about).

Next, read about small binary form, and how it differs from the small ternary form.