Baby Audio Atoms Review: Physical Modelling Made Simple

May 16, 2025

Physical Modelling Without the Physics Degree

Physical modelling synths have a reputation: brilliant in theory, a slog in practice, with pages of parameters that only make sense if you know how a cello string behaves. Baby Audio's Atoms throws most of that away and gives you six knobs and a randomiser. The surprising part is how much it gets out of them.

What It Is

Atoms is a physical modelling synth built on a simulation of masses connected by springs. A virtual bow excites the network and makes it vibrate, and you change the properties of the system rather than shaping a waveform. Baby Audio developed the model with Silvin Willemsen, a researcher at Eindhoven University of Technology. It runs as a plugin or standalone.

It's not trying to be a realistic violin or flute. The idea is sounds that behave like acoustic instruments but don't exist in the real world.

Baby Audio Atoms physical modelling synth main panel

The Sound and the Architecture

The six main controls sit around a visualiser that shows the mass-spring network moving as you play. They are Chaos, Order, Force, Overtones, Drive and a resonant lowpass filter, and each one changes how the network behaves rather than just its tone. Below that, you choose between four sonic profiles, each a different structure of the network, and set attack, release, movement, modulation and vibrato.

The results are bowed, breathy and constantly shifting. Think somewhere between strings, glass harmonica and pitched percussion, with a slightly unstable, organic wobble that samples rarely have. Every one of the six main parameters can be automated with built-in motion options, so pads drift and evolve on their own. In a mix, these sounds sit nicely in the mid and upper range as a texture layer behind a piano, guitar or more conventional synth pad.

What It's Good At

The randomiser is far smarter than most. It adjusts each parameter based on how it relates to the others, so you get usable patches rather than noise, and you can lock parameters or limit their ranges. The Recycle button then generates variations on the current patch, which is a quick way to find a cousin of a sound you already like.

The effects in the bottom panel are part of the physical model itself, apart from the Space reverb, so modulation and movement come from the sound rather than being added on top. There's MPE support too, and with an MPE controller the bowed sounds really come alive. The 250+ presets give you plenty to start from.

Baby Audio Atoms plugin settings and effects controls

Where It Falls Short

It's a specialist. You won't get a punchy bass, a supersaw lead or a clean pluck out of Atoms, because that's not what the model does. If you want one synth to cover everything, this isn't it.

The simplicity cuts both ways. Six main knobs make it quick to use, but there's no deep modulation matrix or per-partial control if you want to go further, and you're working inside what Baby Audio chose to expose. You'll also find many patches share a family resemblance after a while, which is the nature of a single synthesis model.

How It Plays

A word on workflow. Because there are so few controls, Atoms rewards a play-first approach: load a preset, hit the randomiser a few times, lock the parameters you like and nudge the rest by ear. It's much more like playing an instrument than programming a synth, and that's what sets it apart from more academic physical modelling plugins.

Who It's For

Film, TV and game composers, ambient and cinematic producers, and anyone who uses sample libraries for textures and wants something less static. It's also a good fit for lo-fi, indie and downtempo producers who want an organic, slightly strange layer in a track. If you mostly make club music, you'll use it for the occasional atmospheric bed rather than every day. New to synthesis types? Our guide to the different synthesis types explains where physical modelling fits.

Baby Audio Atoms factory preset packs

Key Features

Physical modelling synth based on a mass-spring network excited by a virtual bow
Six main controls: Chaos, Order, Force, Overtones, Drive and resonant lowpass filter
Motion options to automate the main parameters
Four sonic profiles, each with a different network structure
Attack, release, movement, modulation and vibrato controls
Randomiser with locks and range limits, plus Recycle for variations
Effects built into the model, plus Space reverb
MPE support, 250+ presets