KaoX

Name: KaoX
Price: 59 USD
Author: XILS-lab

by XILS-lab · Synth · FM and analog hybrid synth

Not rated yet

KaoX combines eight-operator FM synthesis with analog-style oscillators and filters and chaotic modulation, across two layers.

It has arpeggiators, a four-track sequencer and over 500 presets, for €59 on sale (about $66.99).

Best for: Keys & Synths, Bass, Sound Design. Genres: Electronic & EDM, Ambient & Cinematic, Pop.

Keywords: FM, analog, hybrid, arpeggiator, evolving, sequencer, subtractive, textures, CPU-heavy, eerie, 80s, basses, cinematic, heavy, inspired by, preset-driven, sound design.

What it does

KaoX is a hybrid of FM and analog synthesis with chaotic oscillators and modulators, inspired by Yamaha's rare early-1980s GS1 eight-operator FM synth. The developer describes it as combining "traditional subtractive synthesis with advanced chaos modulation techniques".

Two layers: played single, double or split, each with its own full engine.
FM section: eight operators per layer in two banks with independent pitch and two outputs; each operator has its own LFO, envelope, low-pass filter, 2D keyboard follower pad, ratio or fixed frequency, and wheel and aftertouch access.
FM algorithm matrix: a matrix for setting up operator routing, always on screen when needed.
Analog section: two continuous-waveform oscillators, two zero-delay analog filters, four D-ADSR envelopes and four output VCAs per layer.
Chaos: two chaotic oscillators and two chaotic modulators for unstable, evolving movement.
Performance: two arpeggiators with play or unison modes, and a four-track sequencer with independent gating per track that can also act as a modulation source.
Effects and presets: four effects with independent routing and more than 500 presets from professional sound designers.

This is version 1.0.3. A demo can be downloaded, and a 15-day time-limited full licence is available.

Source: XILS-lab product page

When to use it

KaoX is the pick for FM sounds with an analog and unstable edge: bells and keys pushed through analog filters, or chaotic textures that never repeat. Compared with Pigments 7 and Phase Plant, it is narrower, with no wavetable or granular engines, but its eight-operator FM with per-operator envelopes goes deeper into FM than either. Compared with Native Instruments' FM8, which MusicRadar calls the industry-standard FM synth, KaoX adds analog oscillators, analog filters and chaos sources. It is more CPU-hungry and less immediate than Vital or Serum 2, so check the demo with both layers and unison on your system.

Best for: FM bells, keys and basses with analog filtering, layered and split patches, and eerie, evolving textures.
Genres: electronic, ambient, cinematic and synthpop music.
Look elsewhere if: you want wavetable or granular synthesis too (Pigments 7) or a light, quick synth for modern patches (Vital).
Tip: MusicRadar singles out the 2M, Chaos and Subh algorithms of the chaotic oscillators for distinctive, eerie textures.

What producers say

Reviewers like its rich, unusual sounds; CPU load and a large, dense interface are the main drawbacks.

MusicRadar (2021) said it "produces some wonderfully rich sounds" as a hybrid take on FM and found cross-modulation quick to use, but noted heavy CPU use with many voices, unison or both layers.
KVR users one review so far, 5 out of 5, praising the FM sound and an interface that makes custom sounds easy.
Criticisms: MusicRadar found the window large and the interface less intuitive than some rivals.

Where to buy

PluginFox: $59 (regular $159)
AudioDeluxe: $59 (regular $159)
XILS-lab: $66.99 (regular $225.96) (Listed at €59 (regular €199); converted at €1 = $1.1355 (ECB rate, 29 Sep 2026))
Best Service: $159
Plugin Boutique: $235

Tutorials and reviews

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