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Baby Audio release BA-1 soft synth

Plug-in reimagines Yamaha’s CS01 synthesizer

Baby Audio BA-1 Yamaha CS1 vintage analogue modelled software synthesizer emulation plug-in

BA-1 is the first virtual instrument to be released by plug-in developers Baby Audio, and offers a modern recreation of Yamaha’s miniature CS01 synthesizer. The company say that they have modelled the original hardware with the greatest possible accuracy, but have also added some new and useful features including a second oscillator, FM capabilities, polyphony and more.

Oscillators & Filter

The pair of oscillators promise to deliver the grit and drift that help to make the original instrument popular, and the company say that the triangle and PWM waveforms will be of particular interest to those searching for classic 80s dub sounds. A crossfade parameter has been introduced to allow users to blend between the two oscillators, and an additional slider offers a new FM oscillator which can be mixed in either an octave above or below Oscillator 1.

An analogue-modelled 24dB low-pass resonant filter section follows, and much like the original device, will begin to self-oscillate when pushed into the 95 to 100 % range. An Envelope section then offers the usual attack, decay, sustain and release controls, and benefits from the addition of a switch to sync the settings to the host DAW’s tempo.

Modulation & Effects

Next up is a simple LFO section which Baby Audio describe as being “easy to master and hard to mess up”. Just two controls are present: Speed and Amount, along with a toggle switch that allows the section to target either Oscillator 1 or the instrument’s filter.

Another new feature then appears in the form of a Sidechain section, which can be used in Internal and External operation modes. When the former is active, the section will generate a 4/4 ducking pattern in time with the host DAW’s tempo, and selecting the latter allows the presence of an external input to duck the level of the instrument. A single Amount control determines the level of ducking applied, and the section can be placed either before or after the plug-in’s built-in effects.

Inspired by cheap rack and pedal effects from the 1980’s, the dedicated effects section promises plenty of retro colour and character. A Tone section houses a pair of shelving filters, whilst Drive provides analogue-modelled distortion, with a Circuit mode emulating the effect of circuit-bending the original instrument, and an OD setting replicating the effect of an overdrive pedal. Time-based effects are also included, with Delay, Reverb and Chorus sections all providing a range of sonic options based on low-cost rack hardware.

The CS01 was capable of being powered by batteries, and would exhibit strange artefacts as the available power decreased. Baby Audio have modelled and exaggerated the behaviour, which can be introduced using a slider next to the plug-in’s master volume control, allowing users to dial in increasingly dramatic pitch fluctuations, distortion and noise.

Check out the company's tutorial video below to hear the BA-1 in action.

The instrument comes loaded with over 500 presets, and also boasts a Re-Gen function which will automatically reconfigure the plug-in’s settings in order to generate a new random patch.


BA-1 is supported on PCs running Windows 7 and above, and Macs running macOS 10.7 and higher. It offers native compatibility with Apple’s M1 and M2 processors, and is available in VST, VST3, AU and AAX plug-in formats.

Pricing & Availability

BA-1 is available now, and is currently (25 April 2023) being offered for an introductory price of $49, reduced from its full cost of $99.

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