Introduction

Rumble is a multi-band bass synthesizer designed for expressive, layered sound design. Its architecture splits every voice into three frequency bands — Body, Character, and Air — each with its own oscillator, waveshaper, effects, and gain controls. This approach lets you sculpt the low-end, mid-range, and top-end of a sound independently before they merge through a shared filter stage, multiband compressor, and master EQ.

Design Philosophy

Most synthesizers treat a voice as a single signal. Rumble treats it as three parallel lanes that converge:

Each band can use a completely different oscillator type. After independent waveshaping and gain, the bands are merged, filtered, and processed through per-band effects, a multiband compressor, and a parametric EQ.

Available Formats

Interface Overview

Click a zone to learn more about it.

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Signal Flow & Architecture

Rumble splits every note into three independent frequency bands — Body, Character, and Air. Each band is synthesized, shaped, filtered, and processed separately before being merged and sent through a shared output stage.

The Three Bands

The band splitter divides the spectrum at two adjustable crossover points. Each band covers a distinct frequency range and serves a specific sonic role.

Crossover Frequencies

The two crossover points define where each band begins and ends. Both are adjustable and modulatable.

• A minimum 1-octave separation is enforced between the two crossovers.
• Both frequencies are modulatable — automate them for moving filter-like effects.

Band Controls

Each band can be independently leveled, panned, isolated, or removed from the signal path.

Oscillators

Each band independently selects one of nine oscillator models. Every oscillator shares a set of common controls, plus type-specific parameters.

Common Controls

Analog

Dual-oscillator design with band-limited antialiasing.

Morpho

Phase distortion synthesis with multiple nonlinear transformations.

Phonem

Vocal synthesis using the VOSIM formant algorithm. Generates up to 5 parallel formant peaks tuned to vowel frequencies.

Fold

West-coast synthesis inspired by the Buchla Music Easel. Uses ADAA antialiased digital audio for clean, alias-free folding. Includes a Vactrol-modeled lowpass gate.

Timbral

Wavetable oscillator with 90+ tables and six phase distortion modes. Categories: Analog, Bass, Complex, Digital, Formant, Harmonic, Noise, Pad, Sync, Vocal.

Noise

Dual noise source with spectral shaping. Over 90 sources across categories: Acoustic, Impact, Machines, Organic, Static, Transient.

Sampler

Sample playback engine with a curated library of mono bass samples. Categories: Sub, Lazer, Reese, Instruments, FM, Drone, Distorted, Complex, Analog.

Kick

Specialized drum synthesis engine with a transient sample layer and a tone synthesis layer. The pitch starts high and drops following an exponential curve.

Prism

Dual-carrier, dual-modulator FM synthesis with cross-modulation. Uses cubic nonlinearity on the modulators for a denser, more aggressive spectrum than standard FM.

WaveShaper & AM Injector

Each band has an independent WaveShaper positioned after the oscillator and before the band gain. It applies nonlinear transfer functions to shape the harmonic content.

Modes

Clipper Punchy, saturated

Hard/soft clipping — compresses peaks for a driven sound

Sine Warm, musical

Sinusoidal folding — smooth, organ-like overtones

Foldback Complex, rich

Symmetric wave folding — dense harmonics that change with input level

Hyperfold Dense, metallic

Extreme multi-stage folding — very harmonically rich

Rectify Bright, doubled

Full-wave rectification — doubles the fundamental frequency

Damped Gentle, warm

Soft saturation with built-in high-frequency rolloff

Diode Gritty, analog

Asymmetric diode-style clipping — adds odd and even harmonics unevenly

Noise Textured, gritty

Noise-modulated distortion — adds stochastic grit

Soft-Ring Subtle metallic

Gentle ring modulation

Hard-Ring Inharmonic

Aggressive ring modulation

AM Injector

The AM Injector enables amplitude modulation between bands. Each band can receive AM from the other two — one band’s amplitude directly modulates another’s signal level. AM Depth controls how strongly the modulation is applied. If Body has a slow sub-bass and Character has a mid-range tone, applying AM from Body to Character will imprint the sub-bass rhythm onto the mid-range level, creating rhythmic pumping, tremolo effects, or spectral interaction between bands.

Filters

Rumble includes six filter models spanning classic analog hardware emulations, vintage synth circuits, and more creative designs. Two filter slots (A and B) are available, with three routing modes: Single (Filter A only), Serial (A feeds into B for cascaded processing), and Parallel (both run simultaneously, blended with the Blend control).

Analog

ARP 4023 circuit emulation — the filter from the ARP Odyssey. Warm, smooth, and musical with circuit-modeled nonlinear behavior. Self-oscillates at high resonance.

Variable

Multi-mode filter inspired by the Oberheim Xpander. Thick, saturated, and characterful, with eight topologies ranging from classic 4-pole lowpass to complex multi-response combinations.

Ripple

Multi-resonant filter that creates multiple peaks around the cutoff frequency. Each Ripple step adds another resonant peak — from subtle coloring at low values to dramatic resonant ringing at high values.

Swirl

Combined phaser and flanger implemented as a filter module. Three phaser modes and three flanger modes — modulate Cutoff with an LFO for classic sweep effects.

Flanger Modes

Phaser Modes

Scream

Korg MS-20 filter emulation — raw, aggressive, and unruly. Self-oscillates violently at high resonance.

Formant

Vowel filter with seven morphable formant sequences. Automate Cutoff for talking and singing filter effects.

Effects

Each band has an independent effect slot with 10 available types, applied after the output crossover.

Common Controls

FX Feedback Loop

Every effect slot includes a feedback loop — the output is fed back through a delay and saturation stage. Soft clipping prevents runaway. This turns any effect into a self-resonating processor.

Cabinet

Speaker cabinet simulation with impulse response processing. The Model control morphs between virtual cabinets ranging from small combos to large speaker stacks, adding the color and resonance of physical speaker enclosures.

Chorus

Modulated delay-based chorus with pitch shifting, spectral enhancement, and optional degradation. Erode introduces pitch instability at high values.

Delay

Four delay algorithms covering clean digital repetition to degraded tape echoes and spatial motion effects.

Digital

Complex lo-fi degradation: fuzz distortion, dispersion, chorus, frequency shifting, sample rate reduction, tremolo, and comb filtering.

Drift

Spectral DSP engine combining comb filtering and frequency shifting. Creates metallic resonances, inharmonic textures, and liquid timbral movement.

Neuro

Spectral transformation engine combining phaser, chorus, and drive to sculpt rich, evolving harmonic textures. From subtle movement and warmth to deep, complex timbral mutation.

Reverb

Five reverb algorithms from general-purpose to specialized convolution types.

Shifter

Pitch and frequency shifting with spectral destruction. Combine pitch shifting with frequency shifting for complex, inharmonic transformations.

Smasher

Transient-focused compression and saturation. Layered waveshaping and spectral enhancement for perceived loudness increase.

Trasher

Destructive distortion chain: fuzz → waveshaping → spectral shifting → dynamic compression → convolution with analog device impulse response.

Modulation

Rumble provides 33 modulation sources that can be routed to virtually any parameter. Each modulatable parameter has 2 modulation slots, each with a source selector and a bipolar ratio (±100%).

Workflow

Macros (1–16)

Sixteen automatable macro knobs in two pages (1–8 and 9–16). A single macro can control multiple parameters simultaneously with independent ratios. Visible to the DAW as automatable parameters.

MIDI Sources

Velocity and Keytrack include a graphical mapper — double-click to add breakpoints, right-click to remove, drag curves to shape the response.

Envelopes

Three ADSR envelopes: VCA (amplitude), Envelope 1, and Envelope 2. VCA always controls voice amplitude. Env 1 and 2 are freely assignable.

LFOs (1–4)

Four independent parametric LFOs. The interactive waveform display shows the resulting shape in real time. Shape, Symmetry, and Pulse Width let you create virtually any LFO shape.

LFO Mix merges all four LFOs into a single complex modulation source. Combine four LFOs at different rates for polyrhythmic patterns, pseudo-random movement, or complex evolving textures.

Analog Drift emulates analog circuit instability — slow, gentle random variation for micro-detuning and timbral wandering that adds warmth without obvious modulation.

MSEGs (1–2)

Two Multi-Segment Envelope Generators, each with up to 128 breakpoints. Double-click to add points, right-click to remove, drag curves to adjust shape. MSEGs have their own preset system.

Random Sources (1–3)

Modulation Matrix

The Matrix tab provides a complete overview of all active connections, organized by destination (Body, Character, Air, Filter, FX, Global, Modulator). Ratio knobs are adjustable directly in the matrix view.

Master Section

Multiband Compressor

A 3-band compressor aligned with Body, Character, and Air. Accessed via the Compressor view tab.

Master EQ

A 4-band parametric equalizer with real-time spectrum analyzer (visibility toggleable in Preferences). Drag control points to adjust frequency and gain, right-click a point to change filter type.

Tuning & Voicing

Global controls — apply to the entire instrument:

Unison — configured independently per band (Body, Character, Air):

Preset Browser

Factory Categories

808

808-style bass and kicks

Dirty

Gritty, distorted sounds

Drone

Sustained, evolving textures

Cyber

Digital, futuristic sounds

Reese

Reese bass sounds

Growl

Aggressive, growling bass

Motion

Rhythmic, moving sounds

Sharp

Bright, cutting sounds

Vintage

Retro, analog-inspired

Wobble

Wobble bass and modulated sounds

Favorites

Your starred presets

User

Your saved presets

Preset Management

MSEG Presets

MSEGs have their own independent preset system. Save and load individual MSEG shapes separately from the main preset — useful for building a library of rhythmic patterns, complex envelopes, or custom curves.

Settings

Accessible from Options → Preferences.

Credits