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.

Video Walkthrough

Watch a full demonstration of Planetary Dispersion here:
https://youtu.be/hGWhsxl7OQk?si=swrM9K9OmarnTQGg

This walkthrough shows how the system uses Unreal Engine to explore planetary atmosphere presets, dispersion, absorption, filtering, distance delay, wind, seismic sound, reverb, and air-column tuning.

Planetary Presets
Planetary Dispersion includes a collection of scientifically inspired planetary, lunar, and exoplanetary acoustic environments. Each preset models unique propagation characteristics based on atmospheric composition, density, pressure, temperature, and speed of sound.

• Jupiter – Hydrogen–helium gas giant with very high sound speed, low atmospheric absorption, and efficient high-frequency propagation.

• Mars – Thin carbon dioxide atmosphere with low pressure, reduced sound speed, and noticeable high-frequency attenuation.

• Earth – Terrestrial reference atmosphere representing familiar acoustic behaviour.

• Venus – Extremely dense carbon dioxide atmosphere with strong high-frequency absorption and efficient low-frequency propagation.

• Titan – Dense nitrogen-rich atmosphere containing methane, producing slower sound propagation and significant high-frequency damping.

• Moon – Vacuum environment where airborne sound cannot propagate.

• Saturn – Hydrogen–helium gas giant with propagation characteristics similar to Jupiter but distinct absorption and dispersion behaviour.

• Europa – Extremely tenuous oxygen atmosphere with near-vacuum conditions, resulting in minimal airborne sound propagation.

• Io – Volcanically active moon with an extremely thin sulfur dioxide atmosphere, producing highly limited airborne sound propagation.

• Neptune – Cold hydrogen–helium–methane ice giant with distinctive atmospheric properties, slow atmospheric temperatures, and unique propagation behaviour.

• Pluto – Dwarf planet with an extremely thin nitrogen atmosphere, resulting in weak airborne sound transmission and rapid attenuation.

• WASP-121 b – Ultra-hot gas giant exoplanet with extreme atmospheric temperatures and very high sound speed, producing distinctive propagation characteristics.

• Sci-Fi – Stylised atmospheric model with exaggerated dispersion, filtering, and propagation effects for creative exploration.

• Neutral – Unprocessed reference preset for direct comparison with the simulated environments.

Test Sounds (0 Key / Cycle):
A diverse collection of reference sounds is included, featuring pink noise, sine tones, percussion, piano, strings, brass, woodwind, clarinet multiphonics, and key clicks. Together they demonstrate how different source materials respond to planetary propagation, absorption, dispersion, pitch, and atmospheric filtering.

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 shift based on the speed of sound in the selected planetary atmosphere. This is intended for air-column sound sources, such as voice, flute, clarinet, saxophone, trumpet, trombone and other resonating air-column instruments. The shift changes the tuning while keeping playback speed unchanged.

• Voice Formant Colour
  Applies an optional vocal colour effect after the air-column pitch shift. This does not deliberately transpose the source audio. Instead, it moves a set of formant-like resonances using a Biquad filter bank, allowing the voice to sound darker, brighter, larger or thinner while leaving the main pitch-shift path unchanged. This is an approximation rather than true vocal formant analysis or resynthesis.

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

Interactive Features:

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

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

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.