What Makes FOAM Different
Most synthesizers that produce “bubble” or “water” sounds use either samples or basic noise shaping. FOAM takes a fundamentally different approach: it simulates the actual physics of gas bubbles in liquid — how they form, resonate, interact, and burst. This means:- Bubble pitch is physically accurate — determined by size, liquid properties, and pressure
- Decay and damping respond to the medium — water sounds different from honey because the physics are different
- Collective behavior emerges naturally — dense bubble populations interact and influence each other
- Surface effects are modeled — reflections, secondary emissions, and interference patterns arise from the physics
Core Acoustics
FOAM models the complete lifecycle of a bubble burst event:- Film rupture — the thin cap breaks, producing a broadband transient
- Cavity resonance — the open cavity rings at a pitch determined by bubble size and liquid properties
- Damping — the oscillation decays through multiple physical mechanisms that depend on bubble size and liquid viscosity
Population Effects
When many bubbles are present simultaneously, FOAM models their collective behavior:- Dense bubble clouds affect each other’s resonant behavior
- Statistical size distributions create natural spectral profiles
- Spatial proximity between bubbles creates organic pitch and amplitude variation
Foam Structure
The Topology system models how structured foam evolves over time:- Foam coarsens as bubbles grow and shrink
- Structural rearrangements produce characteristic acoustic events
- Phase transitions create dramatic textural shifts
- Stressed foam exhibits yield and avalanche behavior
Surface & Secondary Effects
FOAM also models phenomena that occur at and above the liquid surface:- Surface reflections create interference and depth cues
- Cavity collapse can produce secondary acoustic events
- Depth and pressure affect pitch
- Non-spherical deformation adds organic modulation