Baby Audio’s BA-1 is like the legendary Yamaha CS-80’s baby brother

Derided as little more than a toy upon its release but beloved by 90s dance producers, Yamaha’s CS01 has been largely overlooked by plugin developers – until now

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Baby Audio BA-1 Soft Synth

Image: Baby Audio

Review Overview

Our rating


Our verdict

Rich, warm sound redolent of past classics
Simple and straightforward synthesis engine
Enhancements increase versatility and not complexity
True to the spirit and soul of the original CS01

No option to switch from glissando to portamento
 Sudden switching to filter self-oscillation sounds unnatural
LFO interferes with oscillator crossfade

Designed as an introduction to synthesis with just a single oscillator, a small keyboard, battery power and a built-in speaker, the CS01 was the final flourish of Yamaha’s analogue synth era. It’s a far cry from its venerable stablemate, the mighty CS-80 but, make no mistake, within the CS01 beats the heart of a true analogue monster.

Understandably, plugin developers have tended towards the beastly CS-80 when it comes to modelling Yamaha’s classic synth line. But not Baby Audio, which has chosen the unassuming CS01 as the inspiration and the basis for its first-ever instrument, the BA-1.

Doubling up

Sticking to the motto, “It’s an evolution, not an emulation”, Baby Audio has created an accurate model of the CS01 but enhanced it with new features that expand its sonic capability, while remaining true to the original concept.

One upgrade is the addition of a second oscillator that can be combined with Oscillator 1 using a simple X-Fade slider. Oscillator 1 is a very close emulation of the CS01’s single oscillator, while the new one is slightly different.

Both oscillators offer a choice of triangle, saw, square and fixed-width pulse waves, while the noise generator has been removed from Oscillator 1’s octave selector and now replaces the pulse wave modulation option in Oscillator 2. The new oscillator’s pitch slider operates differently too, with an option to switch from the fine-tuning found on the original (± one semitone) to a coarse tuning mode offering ± one octave.

Alongside the new oscillator is a so-called FM (frequency modulation) oscillator. This isn’t true FM – where one oscillator modulates the frequency of the other – but is instead a tone generator with an FM-like sound that’s mixed into the signal path. It can introduce fizzier or woodier harmonics, and although it is a bit of a cheat, having those extra harmonics to play with is all for the good.

Diss the gliss

The glissando effect of the original is here, too; rather than sliding smoothly between pitches in the way portamento does, glissando advances in semitone steps. At fast speeds, this is indiscernible from portamento, but at slower speeds, you clearly hear the stepping. Although authentic to the original instrument, this isn’t the nicest or most usable of effects, and we’d prefer the option to switch to portamento mode.

BA-1’s filter section is an improvement on the somewhat flaccid 12 dB-per-octave filter found on the hardware. Instead, this filter is a model of an analogue 24 dB-per-octave low-pass, similar to the filter found on the CS01 mkII. Also like the mkII, BA-1 has a resonance slider in place of the original’s on/off switch.

Though this is a nice-sounding filter, it isn’t the most exciting we’ve heard. However, the synth has a nice overdrive stage in its effects section that can make up for this (and then some). BA-1’s filter can emulate self-oscillation, but as with the FM section this is somewhat of a cheat; self-oscillation is either on and is all you hear, or it’s off, with the switchover between the two being sudden and incongruous.

Baby Audio BA-1
Baby Audio BA-1 in Magenta


BA-1’s single ADSR envelope is hard-wired to amplitude, but can also be dialled in to control the filter, albeit only in a positive polarity. A nice touch here is that the envelope’s attack phase can be synced to your DAW for perfectly-timed risers and pulses.

In contrast to the envelope, the single LFO can drive only one source, with a choice of either Oscillator 1 pitch or filter cutoff. Weirdly, no matter what it’s set to modulate, increasing the LFO amount affects the oscillator X-Fade balance too, which can be a nuisance.

Baby Audio BA-1

Alongside the LFO sits a sidechain control – rather unique for a synth. This operates much like a ducker, reducing the volume in response to another signal. When set to internal mode, BA-1 produces a 1/4-note pulse, synced to the host DAW, which implements the sidechain effect. Conversely, when set to external mode you can bus in another track in the production to drive the ducking, which can be a lot of fun. The ducking can be applied pre or post an effect section that provides high and low shelving EQ, a flexible overdrive, tempo-synced delay, a nice sounding reverb, plus a luscious Juno-style chorus.

As a final doff-of-the-cap to Yamaha’s original, Baby Audio has included a switchable speaker emulator to mimic the boxy tone of the CS01’s internal speaker, and a slider that adjusts the ‘battery charge’ level; as the charge is reduced so the synth’s pitch becomes increasingly unstable and its output increasingly noisy. These features are silly but are fun to play with and ideal for creating degraded lo-fi sounds.

Big baby

There’s no denying that, like the original CS01, BA-1’s synth engine is quite limited and simplistic, but this should be seen as a feature, not a shortcoming. The basic nature of the synth invites immediate playing, while Baby Audio’s upgrades add sonic depth without adding conceptual complexity. Indeed, it’s a testament to how well Baby Audio has captured the spirit and soul of CS01 that BA-1 feels so toy-like.

Baby Audio BA-1

What isn’t toy-like, however, is BA-1’s sound, which is rich, warm, and incredibly pleasing. The additional oscillator brings with it a flavour of the CS-80, and this is reflected in the number of classic CS-80-inspired sounds found amongst the 500+ presets.

There are also shades of Roland Jupiter synths here, especially when it comes to brass and string sounds, as well as hints of a Sequential Prophet 5 and Oberheim OB-8 in the lead and pad department. This is a surprisingly wide spectrum of versatility for such a basic instrument and so, despite the oddities sprinkled throughout, we can’t help but love this baby beastie.

Baby Audio’s BA-1 is available now for $99 at

Key features

Plugin instrument in AAX, AU and VST formats
Integrated parameter and waveform display
Two oscillators plus FM-like oscillator
24 db/oct resonant low-pass filter
Single ADSR envelope with attack stage sync to host
Single LFO
Sidechain stage for ducker-style effects
Effects section with EQ, overdrive, delay, reverb and chorus
Speaker and battery charge level emulation
Regen button auto-creates useable patches
Four colour schemes
MIDI learn mode


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