Welcome to Leviathan, a fourth generation Reaktor instrument. Here is the user manual, describing the features and behavior of the default Leviathan configuration. Leviathan is member of the Metamusic series, which are instruments for Reaktor and Reaktor Session.


Feature Summary


  • Global clock with symmetric shuffle
  • Step record from MIDI and on-screen keyboard
  • Three sequencers with trigger filtering and transmute
  • Three linked pattern and phrase designers
  • Arpeggiator


  • 100 concurrent modulations with 50 sources
  • Click-free selection of modulation source
  • Two polyphonic LFOs and one monophonic LFO
  • Two envelopes with slope modulation
  • Four oscillators with >30 waveforms
  • Ring modulation and dual soft sync
  • External input; oscillator effect modes
  • Two 4-way vector mixers
  • Two filters with serial and parallel output
  • Modulation of serial filter feed
  • Morphing of filter type and overdrive

Output Effects

  • Low-CPU design throughout
  • Stereo output stage with peak and mute
  • Polyphonic pan modulation of each filter output
  • Flange, chorus, stereo tempo delay, and reverb

Other Features

  • Waveform display; multiple metering modes
  • On-screen keyboard
  • Multilevel mapping of key scale
  • Sophisticated CPU usage management

Launching the Ensemble

First you probably want to try it out. When you launch the instrument, it starts playing itself automatically. It may take a minute or so for the ensemble to load, because it is very large; thankfully Reaktor 4.12 no longer crashes when switching between large ensembles.


You will need v4.12 of Reaktor. A 1GHz or faster processor is recommended. With slower machines ou will be able to open the simpler snap sets; more complex snap sets usually work if voices are reduced to 3.

Auditioning the Snaps

Now if you open the snapshot window, you can click through the snaps. Snaps beginning with the same word are in the same set . You can change to different snaps in the same set, and you will hear dramatic changes without any clicks or other interruptions (due to the Metamusical unique "switchless matrix architecture" ) . Then you may want to read this manual, and perhaps the tutorial at its end.

Architecture Overview

Audio Path


The instrument provides four oscillators, each with 40 modes, including special waveset and effects modes. Soft sync and amplitude modulation is avialable on all oscillators. FM is available for FM oscillators. Ring modulation and "bang oscillators" are also selectable. In addition, effects modes can patch in effects blocks instead of oscillators. Any osicllator, mixer, filter, output, or an external input can be the input for AM, FM, sync, and effects.

All oscillators feed two vector mixers. Each vector mixer adjusts the oscillator mix into each of two separate filters.

The two FM filters operate both in serial and in parallel, with adjustable feed from filter 1 to filter 2. Filter 1 is switchable between more than a dozen filter types. Filter 2 can morph between different filter types and filter drive levels. Both filters and the serial feed path include switched saturation units.

There is optional polyphonic limiting of each filter output prior to the amplitude envelope. The instrument also includes simple pan, chorus, echo and reverb units.

Switchless Matrix

The heart of this instrument is its switchless matrix architecture, providing dozens of modulation sources and modulation targets.

  • Sources are LFOs, envelopes, sequencer control values, real-time controllers, and various kinds of compound matrix modulations.
  • Targets are audio parameters such as Contour , Pitch , Sync , Horiz , Vert , Freq , Res , Drive , Feed , and Pan.

Most targets let you adjust the amount of modulation from pitch tracking and four other modulation sources. For most targets, modulations are scaled, curve-shaped, and either clipped or mirrored, within adjustable ranges. Moreover, you can change between 32 different sources in real time without interrupting the sound.

Pitch and Gate Path


Sequencer Routing

In step-record mode, the sequencer can receive notes from the on-screen keyboard and external MIDI, as follows:

  • For the pitch data, the sequencer generates one note at each step. The sequencer can transpose its own output overall. Also, each sequence contains a sequence of patterns called phrases . The sequencer can transpose each phrase by a different amount.
  • Each sequencer can generate gates of any length. While each sequencer can only create one, single note-on event in each step, the duration of the generated notes may be longer than the step cycle. So the sequencer output is actually polyphonic.

Pitch and velocity go directly to the synth as modulation sources, and in parallel pass to the voice merge macro. The voice merge macro combines all the data from the sequencers, on-screen keyboard, and incoming MIDI (so you can play from external MIDI and use the internal sequencers simultaneously). The voices are allocated on a least-recently used basis, so a fast sequence from one sequencer or MIDI does not steal voices from other sources.

The merged voices pass through an optional arpeggiator, then enter the audio synthesizer.

Synthesizer Routing

The global pitch section first applies any pitch transposition, then passes notes to the scale mapper. The scale mapper can optionally force pitches to different key scales.

After scale mapping, pitch data is sent through the glide generation circuit, then sent to pitch tracking. Pitch tracking can adjust overall tracking not only for output pitch, but also for any pitch modulation applied to other sound parameters.

Oscillator 1 directly uses the global pitch for its own pitch, without further modification. The other three oscillators can each apply their own pitch offset to the global pitch. After any local transposition, each oscillator can optionally apply its own keyscale mapping to transposed pitch values. Then the oscillators each provide their own individual pitch tracking and modulation.circuits.

Pitch data is also sent to the envelopes, which can adjust both their attack time and overall ADSR shape in response to note pitch. Global pitch and envelope data are routed throughout the instrument as modulation sources. After mixing and filtering, the audio envelope is applied to the resulting signal mix, providing clean envelope shaping of the overall sound.


I want somethink less gritty. How do I get a clean sound?

If you want a clean sound out of Leviathan, it's designed to do that too. Here's the configuration:

  • Turn off all filter saturation.
  • In the output section, enable polyphonic limiting on both filters. The limiting is designed so sound can be very clean.
  • In vector mixers, set overdrive to minimum for all oscillators.
  • If using filter 2, either use oscillator input only (for parallel output) or turn off all oscillators and use filter feed only (for serial output). In the latter case, keep filter feed below the half-way point (as describved in manual, this keeps feed below unity gain).
  • If using morph for filter 2, set overdrive to mimumum for all three filter types.

Now you will have a perfectly clean sound, and also, without any audio peaks at high resonance levels, due to polyphonic limiting, sounds even cleaner than res-limited filters in the Reaktor 4 library.

Release Notes

Normalized Patchable Modulation

Throughout Leviathan, patchable sources provide normalized modulation of signal parameters. “Normalized” means that the modulation levels are internally adjusted so that the range of available modulation (controlled by a ‘depth’ slider under the modulation source list) is perfectly usable for all destinations, no matter what sources and destinations you are using.


If you find you want to ‘denormalize’ a control, there are two modifier blocks which provide various means to massage the modulation sources:

  • Modifier 1 provides a fixed-level source (“Fixed1”) available throughout the instrument. In addition, you can select any modulation source and adjust its gain, offset, and its type of slope (you may choose to convert any source between pitch, frequency, amplitude, and linear slopes).
  • Modifier 2 lets you choose two sources and set the minimum/maximum level for each, then crossfade between them using an on-screen control. Often you may wish to map this control to your modwheel or other hard control surface for real-time morphing between two sources.