Daniel Portelli - Planetary Dispersion

Planetary Dispersion is a procedural sound system for Unreal Engine that models dispersion, absorption, and temporal behaviour across speculative planetary atmospheres. It lets you explore how sound propagates through different media, from thin Martian air to dense Titan or Venusian atmospheres, and even fully liquid environments. Frequency-dependent absorption, time-of-flight effects, and low-pass filtering produce subtle but perceptible differences, most noticeable with broadband sounds, allowing comparison between realistic, cinematic, and stylised atmospheres.

Planetary Presets (1–9):
Nine pre-configured planetary atmospheres are provided, each with unique propagation characteristics:

1. Jupiter – Gas giant; fast sound speed, low absorption, high frequencies propagate with minimal loss.

2. Mars – Thin CO₂ atmosphere; slower sound speed than Earth, moderate high-frequency attenuation.

3. Earth – Standard reference; realistic atmospheric behavior.

4. Venus – Dense CO₂ atmosphere; strong high-frequency absorption, low frequencies travel far.

5. Titan – Thick nitrogen-rich atmosphere with methane; slower sound speed, noticeable high-frequency damping.

6. Moon – Vacuum; sound cannot propagate.

7. Saturn – Gas giant; similar to Jupiter with slight differences in dispersion and absorption.

8. Sci-Fi – Stylized atmosphere; exaggerated propagation and absorption effects for creative exploration.

9. Neutral – Reference preset; unmodified sound for comparison.

Test Sounds (0 Key / Cycle):
A selection of sounds, including pink noise, sine tones, percussion hits, and piano recordings, allows testing how propagation behaves under different planetary conditions. Broadband sounds are particularly effective for perceiving absorption and dispersion effects.

MetaSounds, Patches, and Presets:
The system uses Unreal Engine’s MetaSound architecture, with referenced MetaSounds and modular patches to process sound in real time. Presets store planetary-specific parameter sets including speed of sound, absorption, base LPF, atmosphere intensity, water intensity, pressure, offset, and transition time, making it easy to switch between environments or return to default states.

Custom Planetary Sound Controller (Widget):
The central interface for the simulator is a fully customisable widget, allowing users to adjust any propagation parameter independently.

Features include:

  • Air / Water / Water Intensity – Select or blend mediums and transition between atmospheric and underwater propagation.

  • Pressure – Adjusts dense atmospheres to alter speed of sound and high-frequency damping.

  • Speed of Sound – Controls delay and spatial separation cues.

  • Atmosphere Intensity – Scales overall propagation effects.

  • Base LPF & Offset – Fine-tune spectral behaviour and frequency weighting.

  • Transition Time – Controls how rapidly propagation parameters update during changes.

  • Record / Playback – Capture sounds directly in the system, then play them back with all planetary effects applied.

  • Bypass & Dry/Wet Slider – Compare raw and processed audio instantly.

Interactive Features:

  • Move the listener to adjust distance; all propagation is physically modelled.

  • Sound level is constant; no artificial reverb or weather effects are added.

  • All audible changes result solely from atmospheric and propagation modelling.

The simulator combines technical rigour, artistic flexibility, and educational value, allowing users to experiment with planetary soundscapes, study environmental audio behaviour, and create unique atmospheric sound designs in real time.

AI Usage Disclosure:
A generative AI image tool was used solely to create a decorative UI frame element. All audio content, sound systems, MetaSounds, Blueprints, and design decisions were created manually by the author.