Bonang: The Bossed Gong-Chimes of Javanese Gamelan
Bonang: the bossed gong-chimes that carry the melody
The bonang is a row of small bronze kettles with raised bosses, laid on cords in a low wooden frame, and played with two padded mallets by a single musician in a Javanese gamelan. Each kettle is tuned to one note of the scale, and the player strikes them in quick succession to state the melody and to decorate it with rapid figures. Where the kenong and the kempul mark the structure of a piece, the bonang works at the level of the tune itself. It is the instrument that a listener most often follows when the ensemble is at full volume, and it is one of the reasons Javanese gamelan has such a dense and shimmering sound. This page explains what the bonang is, how it is built and tuned, the main types in the ensemble, and how a visitor can hear one in Central Java and Yogyakarta.
How a bonang is built and what it looks like
A bonang is made of bronze, cast in a mould and then finished by hand. Each kettle has a rounded body, a narrow rim and a boss in the centre that is struck. The boss is the source of the sound, and the tuner shapes it by filing and hammering until the pitch is correct. The kettles are arranged in a row on two cords that pass through holes in their sides, so that the player can reach each one without moving the frame far.
The frame, called a rancak, is a carved wooden stand that holds the kettles at a comfortable height for a seated player. In most sets the frame is decorated along its top and sides, and the colours often match the rest of the ensemble. A bonang is therefore both a musical instrument and a piece of woodwork, and a good set looks as well as it sounds when the light falls across the row of gleaming bronze.
The bonang barung and the bonang panerus
Gamelan ensembles usually include two bonang sets, which sound at different octaves. The bonang barung is the middle-register instrument, and it carries the main melody and its ornaments. The bonang panerus is higher, and it plays faster figures that sit above the barung line. The two sets are tuned to work together, and when they play in unison they produce a shimmering effect that is one of the defining textures of the gamelan.
The panerus is often played by a younger or more agile musician, because its figures are quick and the mallet work is demanding. The barung player must hold the line steady while the panerus plays around it. In a well-balanced ensemble, these two players listen closely to each other, and the audience hears a single melodic voice that seems to move between the octaves.
What the bonang does in the music
In Javanese gamelan, the basic melody is called the balungan, and it is usually played by the saron and the gender. The bonang takes that melody and turns it into a fuller and more decorated line. The player adds small notes, repeated figures and rolls around the main pitches, a practice called garap in the local vocabulary. These ornaments give each piece its character, and a skilled bonang player can make the same melody sound quite different from one performance to the next.
The bonang also helps to shape the music’s speed. A player who moves into a fast figure drives the ensemble forward, while a slower, more open pattern allows the piece to breathe. Because the bonang sits in the middle of the sound, its changes are easy to hear, and the other musicians respond to them. A visitor who listens for the bonang will quickly notice how the whole ensemble follows its lead.
Tuning a bonang set to slendro or pelog
Gamelan music is built on two tuning systems, slendro and pelog. Slendro uses five roughly even steps in the octave, and it has an open, bright quality. Pelog uses seven steps that are unevenly spaced, which gives it a deeper and more intense colour. A bonang set is tuned to one of these systems and must stay with it, because each kettle is adjusted to fit the scale exactly. Mixing kettles from different systems would make the set sound wrong from the first stroke.
Tuning is done by hand, one kettle at a time. The tuner strikes a kettle, listens for the pitch, and then files or hammers the boss until the note fits the set. The process is slow, and it requires a trained ear and a good deal of patience. Because each kettle is tuned on its own, a complete bonang set has a sound that no factory process could easily reproduce.
Playing the bonang with two mallets
The bonang is played with two mallets, one in each hand. The mallets have padded heads, often wrapped in cloth, and the player strikes the bosses with quick, light movements of the wrist. The skill lies in moving between kettles smoothly, keeping the rhythm steady, and making each stroke clear without drowning out the neighbouring notes. Experienced players can play long and complicated figures without losing the melodic line.
The player also uses damping, touching a kettle after it has been struck to shorten its sound. Damping keeps the texture clean and allows the next note to ring out clearly. A bonang player who lets every kettle ring for its full length produces a muddy sound, so the technique is taught early and refined over many years.
Where a visitor can hear the bonang
The bonang is heard in every full gamelan performance, and a visitor who attends a palace concert or a village celebration will hear it clearly. In Yogyakarta and Solo, the royal gamelan is a particular draw, because the ensembles there have a long and carefully preserved repertoire. Seats close to the ensemble give the best view of the bonang player’s hands, and they let you hear the decorations that are lost at a distance.
Smaller performances, including workshops and community concerts, are another way to hear the instrument up close. Many cultural centres in the region host regular sessions, and visitors are welcome to watch. Our overview of the Central Java region explains the towns and routes that make the most sense for a trip built around the gamelan, and our page on gamelan in Yogyakarta describes the kinds of performance you can expect in the city.
Common questions about the bonang
How is a bonang different from a kenong?
The bonang is a row of small kettles played with two mallets, and it carries the melody and its ornaments. The kenong is a set of larger pot gongs laid on a frame, and it marks the phrase endings. The two instruments sit at different levels of the music’s structure and have different sounds.
Why does the bonang have two sets?
The two sets, barung and panerus, sound at different octaves so that the melody can be played with more colour and density. The panerus adds faster figures above the barung line, and the combination gives the ensemble its distinctive shimmer.
Is the bonang difficult to learn?
It is demanding. The player must coordinate two mallets, keep a steady rhythm and know the melody well enough to decorate it. Most players begin with simpler parts and move on to the faster figures only after years of practice.
Caring for a bonang set and the tradition around it
A bonang needs careful maintenance. The bronze should be kept dry and clean, the cords checked for wear, and the frame protected from damp and cracks. The mallets must also be looked after, because worn padding changes the sound of each stroke. Good sets are kept in sheltered rooms, and they are checked by a tuner when the pitch begins to drift.
The bonang is also a way of passing on musical skill. Young players often learn the instrument by watching and copying older musicians, and the repertoire is taught by ear and by demonstration. For a visitor, the bonang is one of the best windows into how gamelan music is made, because its melody and ornaments are easy to hear once you know where to listen.
Listening for the bonang in a performance
To hear the bonang well, choose a seat that puts you near the ensemble and watch the player’s hands as the melody moves. Listen first for the main tune, then for the ornaments that wrap around it. Once you can follow the line, the bonang’s role in the piece becomes clear, and you will notice how the other instruments answer its phrases.
A performance is more rewarding when you know what to expect. The bonang is not the loudest instrument, but it is among the most expressive, and it gives the gamelan its singing quality. The next time you hear a gamelan, listen for the row of bossed kettles, and the piece will open up around its melody.
Related guides: kenong, kempul, sinden javanese singer, What the ketipung sounds and looks like, gendhing, Central Java Gamelan: Instruments, Tuning and Music.