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

Designed as an experimental sound design, education, and research-oriented framework that is straightforward to deploy while remaining fully configurable and modifiable for wider application.

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.
• Seismic – Adds a low-frequency seismic layer for quake, volcanic, geological, or subsurface rumble effects.
• Environment Type – Selects reverb and spatial environment presets such as ice chamber, canyon, or open terrain.
• Pressure – Adjusts dense atmospheres to alter speed of sound and high-frequency damping.
• Temperature – Changes the acoustic profile by affecting propagation speed and tonal response.
• Humidity – Shapes absorption and damping behaviour, especially in relation to high-frequency energy. 
• Altitude – Simulates height-dependent atmospheric thinning, changing the perceived density and filtering of sound propagation. 
• Wind – Adds planetary wind ambience, with selectable wind layers for different atmospheric conditions.
• Flux – Introduces ongoing movement or instability into selected parameters, creating more dynamic, less static planetary sound behaviour. 
• Speed of Sound – Controls delay and spatial separation cues. 
• Atmosphere Intensity – Scales overall propagation effects.
• Amplitude Contrast – Controls how strongly loudness differences between planetary environments are exaggerated or reduced. 
• Base LPF & Offset – Fine-tune spectral behaviour, frequency weighting, and band-based dispersion.
• 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. 
• Atmos. Tuning / Air-Column Shift – Applies a pitch or tuning adjustment associated with atmospheric resonance or air-column behaviour. 
• Bypass & Dry/Wet Slider – Compare raw and processed audio instantly.

Installation

Windows:

Download PlanetaryDispersionWin.7z, extract it, then open the extracted folder and run PlanetaryDispersion.exe. Do not move the .exe out of the folder.

macOS:

Download PlanetaryDispersionMac.zip, extract it, then open the Planetary Dispersion app. If macOS blocks the app, right-click the app and choose Open.

Unreal Engine is not required to run the standalone app.

Full project page:

https://danielportelli.com.au/planetarydispersion/

Unreal Engine project on Fab:

https://www.fab.com/listings/f8af172e-9d01-4c82-86ce-555a7b8ed85