Review of Carbon Electra – a 4 oscillator subtractive synth (64 bit VST / AU) from PluginBoutique


Carbon Electra is available from PluginBoutique in 64 bit AU / VST versions typically priced at £39.95.


Carbon Electra was designed by producers, for producers and was developed as an advanced learning tool whilst also being a powerful and easy to use synth.

It’s a 4 oscillator subtractive virtual analog synth with a filter, modulation envelopes, assignable LFO modulators, in-built effects and a step envelope feature which offers lots of creative potential.

Because it has been built as a learning tool, the GUI has been designed so that all features fit onto one page. It is aimed at dance / EDM sounds and features presets from some famous names such as Carl Cox, Freemasons and Mike Huckerby.

Carbon Electra has recently been updated to version 1.5. This brings a number of under the hood tweaks and a few very minor changes to the GUI. It’s actually a very well thought out update that retains the feel and character of Carbon Electra whilst increasing its versatility and sound potential.


This synth is one of those that could be overlooked as another 4 oscillator virtual analog synth but you need to look deeper because you’ll find a very capable synth that is fun, easy and intuitive to use and produces amazing sounds from lush, warm chords to edgy, aggressive leads / basses and excellent sequences too. I’d also say it is capable of producing a much wider range of sounds than those limited to dance / EDM.

Carbon Electra is not trying to copy any particular synth and has its own distinctive sound. Whilst it may not have some of the advanced features of synths like Synthmaster 2 for example, this works to its advantage, making it easy to get to grips with and achieves the dual aims of being a teaching tool and a powerful synth. Whilst Carbon Electra has limited oscillator waveforms, a single filter and no modulation matrix compared to these synths, that for me is part of the appeal. You can get to grips with Carbon Electra very quickly and produce excellent sounds with ease, that’s definitely the role of a teaching synth rather than baffling you with multiple screens and complex signal routings.

The biggest problem I’ve found is that if you adjust a preset sound and save your project, when you next open the project your changes won’t have been saved. This happened a couple of times and I thought I was losing the plot but it is a known bug. I have been a bit lazy like that and relied on saving the project to save the latest settings rather than saving presets, I now save everything as I go along which is a much better way of working anyway.

I’ve used Carbon Electra to create the EP embedded above. It’s a techno infused sound using Carbon Electra as the focus for producing the tracks. Song 1 uses 6 instances; song 2 five instances plus Lancinantes (Inear Display); song 3 one instance plus Lancinantes; song 4 four instances plus Lancinantes.  I’ve used a range of effects including UltraChannel, UltraTap, SP2016 reverb, Octavox, H3000 Band Delays, H949 Dual Harmoniser (Eventide); Cryogen, Convex (Glitchmachines); SpecOps (Unfiltered Audio).

In-depth review

I really like the look of the GUI, it’s very intuitive to use and helpfully everything is included on one screen. It mirrors the signal flow starting with the oscillators, envelopes, a mixer / filter section and the 3 modulation LFOs on the right.

Underneath this are the effects – which look like a rack unit effect – comprising chorus, delay, phaser, distortion and EQ. At the bottom of the screen you have the step sequencer and master controls.

When trying a new synth I’ll usually look at the presets to see what it sounds like. The version 1.5 updates adds more than 150 new presets to the 600 from the original version arranged into categories such as bass, chords, sequences, keys, pads and effects and include presets by some famous names such as Carl Cox, Freemasons and Mike Huckerby. A number of expansion packs are also available.



Oscillator one has pitch, FM and width controls. The version 1.5 update adds an FM modulation switch to oscillator one that allows you to easily create classic FM sounds and also a switch underneath the pitch control to activate multi-voice unison within each oscillator enabling huge multi-saw sounds. Oscillator one can be sync’d with Oscillator two. Oscillators two, three and four have pitch, width and tune controls and oscillators three and four can also be sync’d. The available waveforms are pulse, square, triangle, sine and noise are capable of producing a huge range of waveforms using the mixer.


The mixer has a volume control for each oscillator, an additional noise generator and a +12dB boost to overload the filter. The visual display is an excellent addition, you can easily see the waveform and how it changes as you adjust the parameters and level of each oscillator,

mixer waveform

Carbon Electra has a single filter. That said, it’s an excellent sounding one. It has 5 settings – low pass, high pass, band pass, band reject and vocal. There’s the usual cutoff and resonance settings, a keytrack control, bipolar filter envelope control and a saturation setting. The version 1.5 update adds a true filter bypass as well as new classic analogue style filter modes – Sallen-Key 12dB Low Pass Filter; 6dB Band Pass Filter; 6dB High Pass Filter; Soft OTA 24dB Low Pass Filter. This is an excellent update that allows you to produce an even wider range of tones.

The filter also has a very handy display allowing you to visualise what the filter is doing.


Carbon Electra has two envelopes, an amplifier envelope and filter modulation envelope. These have the standard controls and I really like how they are also presented visually.


There are 3 LFOs provided for modulation. Each of the LFOs have rate, delay, width and phase controls and have the same waveform shapes as the oscillators. They can sync to your DAW tempo or you can manually set the frequency. There are also trigger and mono settings and they can be used with a modwheel assignment control. These LFO modulate different parameters and have additional controls based on what they are modulating. LFO one can be applied to individual oscillator pitch and amplitude; LFO two can modulate the FM of oscillator one, the pulse-width of oscillators two and three, LFO one amount and filter resonance; LFO three can modulate the mix setting of each individual oscillator and filter cutoff.


The effects rack contains a good range of effects and a new distortion mode. These sound very good for inbuilt effects. The immediately notable absence is a reverb but I suspect the developers were thinking that most users would be using a separate reverb effect and you can of course use any separate effects if you prefer. The layout reminds me of guitar effects rack unit and I like the linear look and feel.

step envelope

The step envelope sets Carbon Electra apart from many other virtual analog synths. It is an excellent addition and although you might think this is complex feature, it is incredibly easy to use.

Essentially it is up to 16 steps, auto syncs to your DAW tempo and you can set the rate from a 2nd to a 32nd T . You can control the amp (volume), filter cut-off and the pitch of oscillators two and four. There is also a note switch that enables you to change the pitch of all oscillators. The wave select box is used to select one of the many wave shapes – ramp, ramp reverse, triangle, cosine, cosine-reverse, sine, level, pulse, pulse-reverse, exp, exp-reverse, exp x2, exp x2-reverse, exp x3, exp x3-reverse, exp x4 and exp x4 reverse,

You can apply a different wave shape to each step and there’s also a very cool edit feature which allows you to change the shape of each selected wave type giving virtually unlimited possibilities such as gated effects, reverse effects, shimmery / tremelo effects.

The version 1.5 update adds a step sequencer with extended 28 semitone range and rests with support for pitch sweeps, legato glide and envelope re-trigger. There is also a context menu (right-click on ‘step envelope’) with copy / paste and other features to ease graph editing and allow you to copy data between presets.


The master controls have the expected volume and tune controls but there are also a number of other controls including polyphony and unison controls for voices, tune and stereo. These are very useful controls to further define your sound.
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