1.4 Models and building blocks
When any musicians perform they refer to something pre-existent, something we might call a ‘model’ or ‘referent’. For musicians performing written music, the most important of these (although not necessarily the only one) is the score or part from which they perform. Depending on the particular genre and period in question, the performer may have freedom to choose or alter certain parameters (tempo, dynamics, phrasing, in some cases the notes themselves), but the score will indicate, to a very great extent, what to play. For musicians in unwritten traditions too, some sort of model will always exist. The music may be based on a particular scale or mode; it may involve a specific metre or a repeated rhythmic pattern; it may be based on a text which must be sung or recited; or it may involve particular processes (e.g. the music must speed up or get louder or more complex). In some cases it doesn't matter what melodic phrases are played, so long as they are based on a particular scale, or relate to a certain harmonic progression. In other cases the outline or contour of the melodic phrases may be fixed, but the details of their ornamentation not. The possibilities are endless, but all kinds of music have this in common – that certain things are prescribed or fixed, and others not.
According to this interpretation, perhaps the closest parallel to the conventional composition-improvisation dichotomy is a distinction between music with a relatively high density of fixed elements, and that with a low density (first suggested by Nettl, 1974, pp. 12–13). Most Western art music has a relatively high density of such fixed elements, since both the notes to be used and their relative durations are prescribed; many non-Western traditions have a relatively low density, although this fact is often difficult for outsiders to determine without extensive research.
The term ‘fixed element’ suggests the existence of formal constraints (i.e. that something must occur at a particular point in the performance). In some cases, it may be more relevant to talk about ‘building blocks’: where, for example, the music is limited to set melodic phrases or rhythms which may be combined in numerous ways. Whether we talk of building blocks, fixed elements or obligatory features, they can all be thought of as different kinds of ‘model’. A model in this context can be any kind of guide the performer uses to construct music, whether highly detailed (as in most kinds of score, especially of ensemble music) or much less so (‘Play what you like as long as you stick to G major and 4/4’). In a little while, we'll be looking at the kinds of models used in the performance of Indian art music.