For any traditional
gamelan piece, there is usually a basic version of the melody, which is very closely bound to the
form of the piece. There are also many variations on the melody, including versions that include a halt in the rhythm, to give a feeling of
cadence , as well as a variety of more or less embellished versions, which often have two, four, or even eight times as many notes as basic versions of the melody. The signature texture that makes
gamelan music so unusual and easily recognizable is created by having different instruments play different versions of the melody at the same time.
If everything that happens in a piece of music is new, the result sounds too random; some sort of repetition is a very important aspect of all kinds of music. Although repetition is an important aspect of Western music, most Western forms are
linear in concept. As a piece develops, a previous section may return, as a whole or only in part, with or without substantial changes, and possibly with new, unrelated material introduced between repeated sections, or even interrupting sections. (See the course
Sound Reasoning for much more on this subject.) In contrast to this linear conception, the basic organizing principle of traditional
gamelan musical forms is
cyclical . Cyclical forms are based on a constant repetition, without interruptions, of a basic musical idea. In traditional
gamelan music, the repetition is so constant that the last note of each cycle is also the first note of the next cycle. (Modern pieces may have a freer form.)
Cyclical forms are not unknown in Western music. Music that has a constant
ostinato , for example, shares some similarities with
gamelan forms.
Of course, music that is only repetitive becomes boring quickly, so during each cycle some things will remain the same while others change. Much traditional
gamelan music consists of
colotomic cycles, in which the
colotomic instruments (usually
gongs ) play the same exact basic pattern within each cycle, while other instruments play a melody that varies from one cycle to the next. As a simple example, a form might be based on eight beats, with a large gong playing on beats four and eight of every cycle, and a smaller gong playing on beats five and seven. Some forms have a cycle even simpler than this; others can be very long, with a complex colotomic pattern playing out over a cycle that is more than 200 beats long. Many pieces (with different melodies) may be based on the same form (colotomic pattern), and pieces based on a traditional form will include the name of the form in the piece's title.
Typically, the pattern is repeated many times in the piece, forming a continuous cycle, with strokes from the larger gongs marking the most important beats (for example, that crucial last/first beat of the cycle). A piece will also have a basic melody, and some form of the melody will also occur in each cycle. The unvarying colotomic pattern, along with the basic melodic idea, provides the stability for the music, while interest and variety are provided by the many, often complex, variations on the melody.