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Musical Form (Part II)By Merryn BroseSonata FormThis is a form that is very important in music. It is used not only in sonatas, but also in symphonies, concerti, string quartets and overtures. It is sometimes referred to as 'First Movement Form' but this label is quite inadequate as it also appears in the last movement of symphonies, some concerti and sonatas, and even appears as a second movement at times. Sonata form has also influenced one particular type of rondo so much that it is called sonata rondo. Sonata form is based on two tunes, or 'subjects'. The first subject is in the tonic key and the second in a related key, (usually the dominant), to avoid monotony. A Bridge Passage connects the key of the first subject to the key of the second. In more complicated examples there may be several tunes in each subject group. This is called the EXPOSITION and is often repeated. Sometimes this exposition is preceded with an introduction. Then comes the DEVELOPMENT. Here the composer may interweave the two subjects, or concentrate on one and give it to us in various guises. The third main section is the RECAPITULATION, which brings back the two subjects of the exposition, with one difference. The second subject is brought back in the tonic key. Finally there is a Coda to round things off. Sonata RondoA sonata rondo is still a rondo (A B A C A D A, etc) but it takes the sonata form idea of bringing back the second subject in a different key. So the plan of a sonata rondo would be: A B (dominant key) A C A B (tonic key) A. There can also be development - perhaps in place of C. Air with VariationsThis is a form that may turn up almost anywhere: as a first movement, (Mozart Piano Sonata K331), forth movement, (Brahms Fourth Symphony), movement of a Suite, ('The Harmonious Blacksmith') and in independent works such as (Elgar's 'Enigma' Variations) and the vocal solo (Purcell's 'When I am Laid in Earth' from Dido and Aeneas). Variations on a tune or theme can be of many kinds. The composer may vary the melody (or weave other melodies around it), vary the harmony, character, and orchestration or keep a constantly recurring bass and weave different strands of melody above it. However, in each of these types of variation, something of the original must be left. FugueA fugue is a development of the simple round; hence the fugue is essentially contrapuntal or polyphonic (with many voices) as opposed to homophonic (one voice with an accompaniment). Although the origins of a fugue are choral, they can also be instrumental. The tune with which the first 'voice' enters is called the subjectt, and usually this is stated in full before any other voice enters. The second voice enters with the same subject usually a fifth higher, or a fourth lower (answe>r). Meanwhile the first voice weaves another melody above or below the answer (countersubject). When all the voices have made their appearance, we call this the exposition. From here the composer may present the subject in new keys, or the voices may wander off into the discussion of something else or (more likely) of some motif or motifs already heard. There are moments when the subject is not heard, for instance when a composer is moving to a new key or preparing for a new entry of the subject - these are called episodes. Devices a composer may use to vary the subject are:
Finally there is usually a recapitulation, which is simply a clear final statement of the subject in the original key. Sometimes a composer will write a 'fugato' passage in symphony, sonata, or concerto, where the subject is developed in a fugal style, without making a formal fugue of it. This and the previous article on form are elementary explanations on the different form types most commonly used. Forms, however, may be expected to go on developing, and they may be varied endlessly for individual purposes. |
Merryn Brose is a presenter on 5MBS. |
