Additive Power – Noxious Synth RE Reviewed



Noxious is the flagship RE of small French developer zvork, also responsible for the ‘Volt’ CV utilities. Taking “an intermediate route,” zvork was the first to bring additive synthesis to the Rack, with this very competitively priced synth of the generator-modifier variety. Is Noxious worth – ehem – adding to your Rack? Let’s find out.

Noxious Overview

Disclosure: Because I had used my trial on an earlier version, zvork (very graciously) granted me a full license for this review.

Noxious’s audio path consists of one generator, five modifiers, and two multi-mode filters. The generator has a whopping twenty-one modifiable waveforms. including familiar options like sawtooth and pulse waves (10, 20, 33.3, and 50 percent). The waveforms are mostly harmonic but there are inharmonic options, as well, like ‘cymbal,’ a waveform with partials approximately equally spaced and of approximately equal amplitudes.

The modifiers are capable of eighteen functions that can be applied to the whole spectrum or just select frequencies. Functions include harmonic equalization (a one band equalizer that can affect even and odd harmonics separately), duplication (with fine enough controls for detuned oscillator effects), and various forms of noise. Each modifier has controls for what part and how much of the spectrum it affects, keyboard tracking, and one or two function specific parameters.

Generalizing about a particular modifier function’s uses is difficult, because most are quite versatile. One of the most straight forward functions is “Pitch – Tune.” Tuning partials a little, you can turn harmonics inharmonic and vice versa. But, if you move a set of partials, say, an octave, you’ve removed a swath of the spectrum and reinforced another. Neat! “Pitch – Harmonize” is also fun. Even simpler to use than “Pitch – Tune,” it finds inharmonics and drags them to the nearest harmonic position or vice versa. Modulating the amount of harmonization with an envelope, it’s useful for transients; modulating the frequencies harmonized with an LFO, it’s useful for shimmering effects, reminiscent of beating.

The two filters can be used in series or parallel and have  a staggering twenty-three modes. The modes are 6, 12, 24, and 48 db low-pass, high-pass, band-pass, band-reject, and then low-pass again, along with positive and negative feedback comb filters and a vowel filter. The difference between the two sets of low pass filters is that the second’s resonance changes with cutoff frequency. (Precise testing of this sort of thing in Reason 6.5 is a pain, so I’m going off the manual.) I didn’t explore mixing Noxious’s additive and subtractive capabilities in depth but I do appreciate having the filters for more generalized sound shaping.

CV modulation options are quite good, with two LFOs, two mod envelopes, and a ten row mod matrix. LFO rates range from .05 to 25 hz and there are six waveforms to choose from (sine, triangle, saw, square, random, and sampled random) and can be tempo and key synced. I’m a bit disappointed with the beat length options and the 25 hz maximum but it’s not a big deal.

The configuration of the mod envelopes is a pleasant surprise; they have the usual four stages but separate sliders for each stage’s level and time, as applicable. As a second bonus, levels can be positive or negative.

In addition to each modulation source having a dedicated destination slot, there is a simple ten row mod matrix. The LFOs and mod envelopes have dedicated CV outs and there are four utility ins, along with dedicated ins for pitch, volume, pan, and filter cutoffs.

Unusual for a synth of this complexity, Noxious has no effects but this doesn’t bother me in the slightest. Effects are really only necessary for string ensembles and organ emulations, especially in the Reason environment, so I’m glad that zvork to put all of its energies into the synth itself.

Efficiency is much improved from earlier versions; Noxious is more cycle-hungry than Antidote but less so than Uhbik F.


The shorthand used to describe subtractive synthesizers doesn’t really apply to additive synths; one isn’t really more fat, punchy, or vocal than another, at least, not in my (admittedly limited) experience. Additionally, there are no easy comparisons to make. I am quite pleased with Noxious’s sound engine, though. Noxious is about as powerful and flexible as synthesizers get (in Reason, at least).

With novel ways to bend sound, Noxious is perhaps most easily used for textured and evolving pads – and these can be quite good – but to say Noxious is best used for a given type of sound would sell it very short. When you can attenuate just odd or just even harmonics, or add beating to just part of the spectrum or sweep harmonics themselves you have a very versatile synth, indeed. If Noxious is best for a certain type of sound, it’s probably sounds possessing two seemingly contrary qualities at once, e.g., “woody” and “sterile.”

Literature from the developer hints that Noxious was created with inharmonic sounds in mind and Noxious is indeed probably the best synth in the rack for those tasks.

Ease of Use

Learning a new form of synthesis isn’t easy but Noxious’s feature set is very sensible and doesn’t make the process any harder than it need be. I do take issue, however, with the GUI. The layout of the controls is haphazard and the markings are all either low contrast (poor readability in 2D) or bright neon. Further, the bottom weighting of the envelope controls is even worse than Antidote’s and the default settings of many parameters (though I’ve heard that this is determined by the Props) are unhelpful at best. For instance, 0% and 100% keyboard tracking for the filters’ cutoffs are both sensible defaults but Noxious uses 50% – why? For virtually any patch, you’ll have to adjust that parameter before setting the cutoff frequency (the same goes for the Mod Envelope 1 destination). This room for improvement isn’t deal breaker but I did knock off a half star from the rating for it. (If zvork changes the GUI in a future update, I’d be happy to revisit this point.)


GUI aside, I really like Noxious; I think it strikes a nice balance between power (there are literally trillions of ways to combine waveforms, modifiers, and filters) and needing days to set every parameter. Most importantly, it sounds good, which is really all I can ask of it. However, I can think of some reasons why others might not like it. Noxious may give you some shortcuts to additive sounds but programming it is still a more complex process than subtractive synthesis and the patches that come with Noxious aren’t as good as those of other synths I’ve tried. (Though zvork has told me that more presets are to be released soon.) In short, Noxious is going to make you work for your sounds. And, of course, not everyone has a need for an additive synth.

But, for the more adventurous among us, why not Noxious? Based on my experiences with it so far, Noxious is the most – ehem – reasonably priced instrument in the shop.
Very good at what it does but not for everyone.

For reference, I would give Thor 4.9 stars and Subtractor, 4.8.

The following two tabs change content below.
Profile photo of colcifer
colcifer is a multi-instrumentalist with a weakness for harmonies and waltzes. You are likely to find him trolling the Propellerhead forums, pretending to be a synthesizer expert.