In short, many! Gamelan experts the world over normally claim that there are anything between 25 and 40 types; however, so far I’ve counted 70 with the number increasing all the time as people create more different varieties. My count includes seven extinct ensembles (yes, there are actually entire Balinese ensemble types which have now succumbed the fate of the dodo). It’s hard to say which exactly those ensembles no longer exist – fortunately there are photos from the early 1920s of several of them; the others are just names I’ve found in books by Balinese government researchers.
The sheer number of orchestral types in Bali is a reflection of the musical creativity of the Balinese. There are orchestras made from different materials: bamboo, wood, bronze and iron, as well as individual instruments with parts made from brass, skin, horn and shell. Unlike Java, there are no orchestras made entirely from brass. By far the most popular material is bronze, which Balinese call kerawang. Out of the bronze-keyed gamelan ensemble types, the orchestra called gong kebyar which was developed in Singaraja in 1912 is by far the most common and popular with possibly more than 30,000 sets across Bali. The most sacred gamelan orchestra in Bali, called selonding, has iron keys however. This type was until recently a lot less popular due to the taboos surrounding playing and learning it.
Generally, the older gamelan types are made of basic, easily accessible and crafted local materials, such as bamboo (of a number of varieties) and wood (palm, sugar palm and coconut). At a later period came bronze and iron technology, not necessarily in that order.
In the 20th century, there has been somewhat of an explosion of ensemble types, experimenting with additional tones (more than the maximum of seven tones in the older ensembles), as well as adding more keys. Fusion with western instruments is commonplace, something which was less common (but not unheard of) in the past. Before the late 20th century, scales were adopted from Java or indigenously Balinese, but with the influence of the western standardization of A440, there has also been a tendency towards standardization (of more commonly heard Balinese scales), modes, as well as copy the western standard altogether (more frightening for a gamelan researcher such as myself). There are even now innovations which make instruments look like a grand piano (but with bamboo keys) as well as instruments made from trash or recycled materials.
To find out more about Balinese gamelan, visit Mekar Bhuana’s website: www.balimusicanddance.com