Fractaos is a 4-voice polyphonic, multitimbral fractal oscillator/synth voice for Eurorack. From the manual, it’s best understood not as a typical oscillator, but as a self-contained melodic sound source with:
Because it already contains oscillators, envelopes, and filtering behavior, Fractaos can serve as the main melodic engine in a system.
Based on the manual, Fractaos is especially strong for:
It is less like a plain VCO and more like a complex digital voice module that can generate complete melodic material with minimal support.
Fractaos can be played melodically in two main ways:
This means you can use it for:
If you want actual melodic composition in Eurorack, this is the big advantage: Fractaos can hold multiple notes at once.
Each voice contains two oscillators:
The Morph control blends and interrelates them, not just as a crossfade, but as a more complex timbral interaction.
For melodic use, this means each note can have:
This is excellent for: - expressive lead sounds - harmonically rich chord voicings - evolving sustained notes that don’t feel static
The manual divides the sound engines into 3 groups:
These are the most useful for tonal/melodic work.
Examples: - Mandelbrot: crystalline, harmonically rich - Julia: softer and smoother - Cantor: articulated, edgy - Sierpinski: odd-harmonic brightness - Dragon: beating, expressive - Rule30: dense, granular - Lorenz / Hénon / Rössler / Logistic: unstable, evolving, experimental - Fibonacci: warm and musically friendly - Koch: crystal highs, brass-like lows - Hilbert: stepped/evolving rectangle character
For melody, these are your primary palette.
These are more atmospheric, noisy, and pad-oriented: - Cloud - Storm - Aliasing - String - Ensemble - Cluster
These are still useful melodically, especially for: - ambient harmonic beds - blurred chord clouds - sustained note clusters - textural melodic layers behind a lead
These are one-shot percussion models: - Kick - Tom - Snare - HiHat - Cymbal
Interesting melodic use: - tuned tom melodies - kick-bass lines - pitched percussive ostinatos - percussive attacks morphed into harmonic tails
This is one of the more unusual strengths of Fractaos: it can create pitched melodic percussion without needing samples.
This is the most obvious melodic use.
A playable 4-note harmonic voice that can produce: - pads - chord stabs - moving harmony - modal progressions
This makes Fractaos a strong “all-in-one” melodic voice for polyphonic composition.
Although polyphonic, Fractaos can also be used monophonically for a focused melodic line.
A lead line with: - animated timbre per note - expressive internal movement - more complexity than a traditional subtractive voice
Because the primitive can restart per note depending on Loop/Trig settings, the lead can feel highly articulated and “composed,” not just modulated.
Fractaos should pair extremely well with external Eurorack or MIDI arpeggiators.
The switch section matters a lot here:
Each arpeggiated note can have a repeating internal contour, like: - a tiny envelope on timbre - pseudo-acoustic attack behavior - evolving brightness from note to note
This is especially effective for melodic ostinatos that need motion without extra modulation modules.
Drone mode is one of Fractaos’ signature features.
In Drone mode: - all 8 oscillators run continuously - Spread behaves differently - upper Spread range scans preset chord/microtuning structures
Drone mode is not just for noise beds. It can create:
The manual describes 3 zones:
These chord structures include: - major triad spread - minor triad spread - sus/fifths - major 7 - minor 7 - add 9 - add 11 - add 13 - just intonation - 7-limit flavor - 19-TET slice - Bohlen-Pierce subset
This is incredibly useful for melodic composition because you can create:
This is one of the most direct ways to generate melodic harmony from the module itself.
MULTI mode is where Fractaos becomes especially powerful compositionally.
Each of the 4 voices can: - load a different preset, or - remain in LIVE mode
Each voice can also respond to a separate MIDI channel.
You can use a single module as:
Or: - one preset for warm harmonic support - one preset for noisy upper extension - one preset for tuned percussion - one LIVE voice for manual improvisation
MULTI mode turns Fractaos into a mini ensemble rather than a single oscillator.
In a composition, this means one module can generate: - independent melodic lines - register-separated harmonic parts - contrapuntal voices - call-and-response phrases
For a small Eurorack system, this is a huge space saver.
These seem most suitable from the descriptions:
Use these when you want: - recognizable pitch - harmonic stability - musical repeatability
These are great for: - IDM lines - glitch melodies - aggressive synth hooks - mechanistic or sequencer-forward phrasing
These are ideal when you want pitch to remain present but timbre to feel alive and semi-chaotic.
Use for: - generative melodies - evolving ambient top lines - unstable harmonic color
A very musical trick from the manual is that Drum curves can be blended with the second geometric fractal using Morph. That means you can create:
This is excellent for melodic techno, electro, experimental ambient, and broken beat styles.
The primitive-derived modulation can affect: - Morph - Spread - Chaos
For melody, this lets each note have internal shape.
This can make repeated notes feel more expressive without changing the sequence itself.
The manual describes a simplified FM mode:
Then Amount becomes bipolar: - lower half: internal feedback - center: neutral - upper half: primitive 2 modulates main fractal frequency
FM mode is especially useful for: - metallic leads - bell-like melodies - complex bass tones - harmonically rich plucks
Caveat: - FM is not active when main fractal is a Texture - FM has no effect on Drum curves
So for clear melodic FM-like playing, stick to geometric fractals.
Texture is more than a filter amount. It affects: - resonant fractal filtering - formant extraction/application - organic micro-detunings - filter intensity
For melody, Texture can function like a macro control for: - vowel-like tone - body and resonance - subtle acoustic-feeling instability - animated overtones
For clear melodic lines: - keep Texture moderate
For ambient or emotional harmonic content: - increase Texture gradually
Too much may obscure pitch clarity, especially with already unstable fractals.
Fractaos has shared ADSR settings across all four voices.
Because release remains active even with sustain at zero, you can make notes respond differently based on gate length, which is musically useful for expressive sequencing.
Even though only one manual is provided, we can still say a lot about how Fractaos fits into a rack for melody.
Use with: - pitch/gate sequencers - polyphonic CV sequencers - MIDI sequencers - keyboard controllers
Fractaos needs melodic instruction from somewhere, and it responds well to either MIDI or 1V/oct inputs.
Ideal uses: - one sequencer lane per voice - polyphonic chord progression input - separate melodic channels in MULTI mode
If generating pitches from random or CV sources, quantizers are very useful before the 1V/oct inputs.
This helps keep Fractaos in: - scales - modes - chord tones - microtonal frameworks if desired
Because the timbre can already be highly complex, stable pitch organization helps melodic intelligibility.
Even though Fractaos has internal motion, external CV into: - Pitch - Spread - Morph - Texture - Speed - Amount - F-Chaos - P-Chaos
can create evolving melodic expression.
Especially useful: - slow CV into Morph for phrase development - stepped CV into Chaos for section changes - performance CV into Texture for emphasis - light modulation of Spread for ensemble width
Stereo output makes Fractaos especially attractive with: - reverb - delay - chorus - spectral FX - shimmer - resonators
Melodic roles improved by FX: - chords become lush pads - leads become cinematic - arps become spatially animated - drones become harmonic environments
Because it is stereo and multitimbral, a mixer is helpful downstream.
In MULTI mode especially, you may want: - voice balancing - external processing chains - dynamic arrangement control
Result: warm evolving chord clouds with internal movement.
Result: bright, metallic, cutting lead with animated harmonics.
Result: tom/mallet hybrid riffs with defined pitch and transient attack.
In MULTI mode: - Voice 1: bass preset - Voice 2: chord preset - Voice 3: lead preset - Voice 4: LIVE mode for manual tweaks
Assign separate MIDI channels or distinct sequencing.
Result: one module handling multiple melodic layers at once.
Result: sustained harmonic field supporting melodic content.
A few manual-based considerations:
These are not flaws, but they do affect how predictable melodic patching will be.
If I were using Fractaos in a Eurorack composition, I’d see it as best suited for:
Its biggest melodic strength is that it combines: - pitch handling - polyphony - timbral evolution - preset recall - multitimbral arrangement
in one module.
That makes it unusually effective for writing actual melodic/harmonic music in Eurorack, especially if your system is otherwise more modulation- and sequencing-oriented.
Fractaos can be used to create melodic components by functioning as:
For the clearest melodic results, focus on: - geometric fractals - moderate Chaos - careful Morph/Texture settings - ADSR shaping - MULTI mode for layered arrangements - Drone Spread chord sets for harmony
If you want, I can also turn this into:
1. a musical cheat sheet,
2. a “best patch recipes” guide, or
3. a module pairing guide for Fractaos with sequencers, filters, and effects.