Free · in-browser · no signup

Design passive acoustic structures that steer sound by frequency.

Explore acoustic rainbow emitter concepts with an interactive browser-based design workspace. Sketch geometry, choose a target pattern, and watch the directivity update in real time.

Educational concept tool · not a certified solver.

+90° up−90°+90°
7 kHz
13 kHz
Frequency-dependent directivity over a hemisphere
Concept

What is an Acoustic Rainbow Emitter?

A small passive scattering structure placed around a sound source can redirect different frequencies into different angles — the same way a prism splits white light into a rainbow, but for audible and ultrasonic waves.

The structures are single-material, sound-hard features — no electronics, no moving parts. By carefully shaping the geometry, you can produce broadband spatio-spectral emission patterns: low frequencies steered one way, high frequencies steered another, and everything in between mapped along a deterministic angular fan.

This designer is a free, browser-based playground for that idea. Draw geometry, pick a target pattern, and explore how shape choices change the radiated field.

Engineering concept

Five ideas behind the tool

Passive scattering geometry

Single-material, sound-hard features arranged around the source — no electronics or transducers.

Monopolar source model

Treat the emitter as a phasor monopole; superpose scattered contributions from each shape.

Frequency-dependent directivity

Inspect how the radiation pattern morphs across your chosen sweep, kHz by kHz.

Target-field optimization inspiration

Match a desired angle-vs-frequency objective with a fast, surrogate optimizer.

Export for FEM/BEM validation

Take JSON, SVG, CSV and HTML reports out for full-wave simulation and lab testing.

Where it fits

Exploration areas

Directional audio conceptsDrone & aircraft acoustic shaping researchAcoustic sensing & emission designEducation & outreachMetamaterial / scattering ideation
Workflow

From sketch to validation

  1. 1

    Draw geometry

    Sketch blobs, rectangles and arcs on a 10×10 cm canvas.

  2. 2

    Choose target pattern

    Upward redirector, rainbow, λ-splitter, or your own.

  3. 3

    Run surrogate simulation

    Phasor superposition runs live in your browser.

  4. 4

    Inspect directivity

    3D hemisphere, top/side polar, and frequency–angle heatmap.

  5. 5

    Export geometry & results

    JSON, SVG, CSV, PNG screenshots and an HTML report.

  6. 6

    Validate full-wave

    Take exports into FEM/BEM solvers and lab measurements.

Research basis

Where the idea comes from

Inspired by Christiansen, Fernandez-Grande, and Sigmund, “Morphogenesis of sound creates acoustic rainbows,” Science Advances, 2025.

This tool is not affiliated with the paper authors. It is an independent educational and concept-design interface.

Disclaimer
The web tool uses an interactive surrogate model. It does not replace COMSOL, FEM/BEM validation, prototype measurements, or engineering certification.

Ready to design a rainbow?

Open the workspace and start sketching — no account, no install.