Baby Audio BA-1 Review: A Toy Synth With Real Bite

May 21, 2025

Looks Like a Toy, Sounds Like a Beast

Yamaha's CS01 was a 1982 battery-powered monosynth with a built-in speaker. It looked like something from a toy shop, and it quietly ended up on Swedish pop records, 90s digital dancehall and a lot of indietronica. Baby Audio's BA-1 is the first serious attempt to put it in a plugin, and it's a lot more than a straight copy.

What It Is

BA-1 models the CS01's circuit and then adds what the original didn't have: a second oscillator, an FM-style tone generator, polyphony, velocity, DAW sync and a full effects section. Baby Audio's own line is "an evolution, not an emulation", which is fair. It runs as a plugin or standalone.

Baby Audio BA-1 synth plugin interface

The Sound and the Architecture

Oscillator 1 is the CS01 core, with triangle, saw, square and pulse waveforms, and the triangle and PWM shapes are the ones to reach for if you want that bubbly 80s dub tone. Oscillator 2 can be tuned coarse or fine against it, and the FM section adds a tone an octave above or below for a plasticky, slightly glassy edge. That all feeds a 24dB lowpass filter with resonance that starts to self-oscillate around 95 to 100%, then a single ADSR and one LFO, both of which can sync to your DAW.

It sounds raw and warm, with a gritty bite to the filter. Basses are round and bouncy, leads are reedy and a bit wonky in a good way, and the second oscillator gets you some surprisingly big brass and pads in poly mode. In a mix, it has a mid-range focus that cuts through without needing much EQ, which is why the original worked so well as a pop secret weapon.

What It's Good At

Character, mostly. The Battery slider drains the virtual batteries, adding pitch wobble, noise and distortion the further down you go, and the Speaker switch sends the output through a modelled version of the original's tiny built-in speaker. Both are proper lo-fi tools rather than gimmicks.

The effects section is the other highlight. Tone gives you two shelving EQs, Drive has a Circuit mode modelled on circuit bending and an OD mode based on an 80s overdrive pedal, and the delay, reverb and chorus are modelled on cheap digital rack units from the era. Turn all three on and it's hard to make a dull patch. There's a sidechain ducker with an internal 4/4 pattern synced to your host, or external input, which is handy for pumping house and pop chords. Re-Gen creates new patches with each click, version 1.5 added an arpeggiator, and there are 500+ presets including four genre expansion packs covering synthwave, modern pop, lo-fi hip hop and 80s/90s sounds.

Baby Audio BA-1 effects section in action

Where It Falls Short

It's simple on purpose, and that has costs. There's one envelope and one LFO, the envelope can only push the filter in one direction, and the LFO target choice is limited. MusicTech's review also noted that glide is a stepped glissando rather than smooth portamento, which you'll hear at slow settings, and that filter self-oscillation switches in rather abruptly.

The FM section isn't true FM either. It's a tone generator that imitates the sound, so don't expect DX-style bells. If you need deep sound design, BA-1 will feel boxed in. If you want a characterful synth that gets results fast, that's the point of it.

Workflow

Workflow is where BA-1 really wins. The whole synth fits on one screen, there's no menu diving, and every control does something you can hear straight away. You can switch between several colour themes as well, which sounds trivial until you've been staring at the same grey plugin window for six hours.

Who It's For

Lo-fi hip hop, synthwave, indie, pop and anyone after 80s colour without programming for an hour. It's also great for dub and dancehall bass and for bubbly arps in electronic pop. If you want a do-everything synth for modern EDM, there are better choices, but as a quick character synth BA-1 earns its place.

Key Features

Model of the 1982 Yamaha CS01, with a second oscillator and FM-style tone generator
Mono and Poly modes, velocity sensitivity on or off
24dB analogue-modelled lowpass filter with self-oscillating resonance
ADSR with host-synced attack, LFO with host sync
Battery drain and built-in speaker simulation
Tone, Drive (Circuit and OD), delay, reverb and chorus
Internal or external sidechain ducking
Re-Gen patch generator and arpeggiator (added in version 1.5)
500+ presets including four genre expansion packs, resizable window, colour themes