Forms
There are many types of musical forms used to describe the overall harmonic and thematic organization of compositions. Two of the simplest forms are binary form and tertiary form.
Thematic design refers to a piece’s melody, figuration, Textures, and musical characteristics other than harmony, while harmonic structure describes the harmonic plan. The thematic design can suggest a different form than the harmonic structure. The harmonic structure utilizes things such repeats signs and harmonic elements that signal where the phrases really lie.
Binary Form
The most common musical form is binary form, made up of two sections that are normally repeated. It’s easy to identify binary form by looking for repeat signs that mark the two sections. Many baroque and classical styles with dances are binary form.
Because binary form was used with many popular dancers, individual phrases are typically four or eight measures long, while pieces written for concert performance feature varying phrase lengths. The lengths of the sections may also vary, with the B section sometimes being longer than the A section. The form is used in other settings, not just for dances.
A piece must move away from the tonic key to be classified as binary. Major-key pieces commonly modulate to the key of the dominant, while minor key pieces modulate to the mediant or relative major. Baroque-era works sometimes modulate to the minor dominant. Romantic-era binary form pieces often modulate to distantly related keys in the first section, or in the harmonic disturbance at the beginning of the B section.
Baroque-era binary pieces have phrases that are less balanced in length than the classical-era pieces. Sections are extended using sequences or multiple tonicizations before returning to the tonic key.
Types of Binary Form
- Sectional binary – the piece is described as sectional binary if the a section ends with a cadence on the tonic of the primary key
- Continuous binary – the piece is described as continuous binary if the a section ends with a cadence that is not on the tonic of the primary key. The piece must continue to a cadence on the tonic, hence the name
- Rounded binary – when the end of a piece features the entire initial melody or part of it (Labeled as “ A ” if the material is unchanged, and “ A’ ” if it is shortened or altered.)
- Balanced binary – one material from the end of the first section returns at the end of the second, and the material is transposed to the tonic key.
- Simple binary – when the second half our piece features no thematic return from the beginning of the movement, it is called simple binary or simple continuous binary. This form is prevalent in Baroque-era composition. It was most common in the late 18th and 19th century compositions.
Ternary Form
This form has three sections A – B – A. The B section I usually has a different length, rhythm or feel, and dynamics to provide contrast from the A section. The B section in the middle is usually in a different but related key to the A section, like its parallel minor or the dominant.
In Ternary Form, the sections that the letters represent can be longer than usual – representing passages or even a full pieces.
Types of Ternary Form
- Composite (compound) ternary – also sometimes called Trio Form, each section is in Binary Form (either AB or AABB).
- Full sectional ternary – the first section (the A section) ends on the tonic.
- Simple ternary – Each section (A, B, A) is thematically and tonally self-contained and separate from the other two.
Forms in the Music We Play
The Bahamas National Anthem is in rounded binary form. The B section ends with a modified version of the main theme.
BahNationalAnthem-FHorn1