Strike a note on the instrument below and listen to the ring. It doesn't only fade: it pulses, a fast, glittering waver that seems to hang in the air. That waver is deliberate. In Balinese gamelan, metal instruments are built in pairs, and one of each pair is tuned slightly higher than the other. Played together, the two beat against each other, and the whole ensemble shimmers. Balinese musicians call that pulsing ombak, which means waves.
Play C, D, E, G and A in a slow figure and let each one ring. Where does the shimmer come from?
The finished texture
This recipe uses Maru's Gamelan module to make an original texture inspired by that sound. It isn't a lesson in gamelan as a musical tradition, which is a whole world of ensembles, repertoire and teaching. It's a way to hear, and borrow respectfully, one of the most beautiful acoustic ideas in it.
Before you play with the shimmer: if you listen on headphones and then on a single speaker, do you think it will sound the same?
1. Hear what a bar sounds like
A struck metal bar doesn't ring like a string. A string's overtones line up at whole-number multiples of the note, which is why a guitar sounds so smoothly "in tune" with itself. A bar's overtones land at odd, stretched ratios instead, and that's what gives metal its bright, bell-like clang.
An ideal bar's overtones don't line up
In the instrument above, change Instrument between Gender, Saron and Bonang and strike the same key. Each recipe models a different shape and material, so the overtones and the decay change. Now you can hear why a gamelan sounds like metal, before any shimmer.
Why: Physical modeling explains how a strike and a set of resonances make an instrument's voice.
2. Play the five notes
With Tuning on Slendro and Root Note on C, the instrument plays five notes: C, D, E, G and A on the keyboard. The other keys are silent on purpose. Those letters are only where to put your fingers; the pitches are the instrument's own five-note tuning, spaced evenly in this software. Real slendro tunings aren't one fixed scale; each ensemble has its own, and that individuality is part of its identity.
Play a slow figure of three or four of the notes and leave space for each one to ring. Repeat it. Now you have a cycle, and in gamelan music cycles are the frame everything else hangs on.
Why: Tuning systems explores how different traditions divide the octave, and why there's no single correct answer.
3. Tune in the shimmer
Start Ombak Amt at 0, then raise it. Then change Ombak Rate. Which control sets how fast the shimmer pulses?
Two copies, slightly apart
With Ombak Amt at 0 the bar rings cleanly. Raise it and the model adds a paired copy, slightly out of tune with the first, and the two start to beat. Ombak Rate sets how many beats per second. Slow rates sound like a gentle sway; around five a second the shimmer starts to sparkle; much faster and it turns into a buzz. Now you're tuning the shimmer by ear, the way gamelan makers tune a pair.
In Bali the lower instrument of a pair is called the pengumbang and the higher one the pengisep, and ensembles differ in how wide they set the gap. Vitale and Sethares' study of Balinese gamelan measures this across real instruments, if you want to go deeper.
Same idea, different place: this is beating, the same effect that makes a Reese bass growl and a supersaw glow. Here it's tuned on purpose to a steady, sparkling rate.
Why: Tuning systems connects the gap between two frequencies to the speed of the beats you hear.
4. Listen on two kinds of speaker
In this instrument the two copies of each note sit on opposite sides of the stereo image. On headphones each ear gets a slightly different pitch, and the shimmer feels like it's floating around your head. On a single speaker the two copies add together in the air and the beating becomes a clear, regular pulse. Try both to hear how the texture changes on each system.
Why: Stereo and spatial processing explains what happens when two channels are combined into one.
5. Leave room for the ring
Play your figure again, a little slower, with one strike softer than the others. The ring is the music here, so give it space. If notes pile up and blur, lower Decay in the full instrument or play fewer notes. Now the texture breathes, and the shimmer has time to bloom on every note.
Why: Envelopes shapes how long each note owns the air.
Keep it
Press Save in the bar under the instrument at the top and call it "Shimmer". It's a ready-made bed for an intro, an interlude or an ambient piece, and you know the one control that defines it: Ombak Rate.
Quick check
- You press F and nothing sounds. Is something broken? No. In this five-note tuning at root C, only C, D, E, G and A are mapped. The silent keys keep you inside the scale.
- The shimmer sounds wide and swirly on headphones but like a steady pulse on your phone. Which is right? Both. On headphones each ear hears one copy; on one speaker the copies add together and beat clearly. Check your texture on the system your listeners will use.
- Why does a metal bar sound bright and bell-like even on a low note? Its overtones are spread at stretched, non-whole-number ratios, so they don't blend into one smooth tone. A string's overtones line up neatly, which is why it sounds rounder.
Next steps
- Explanation: Timbre and harmonics. Separate the tuning of a note from the partials that give each bar its color.
- Sideways: Planning and recording samples. Capture a sounding object and compare its decay with your modeled texture.
