201 MB

Annulus is a polyphonic resonator and effects engine built for sound designers who think in texture, not presets. At its heart is a faithful implementation of the physical modeling engine behind Mutable Instruments’ Rings — one of the most celebrated modules in the history of Eurorack — paired with a full effects chain and a visual interface that breathes with the sound.

Six modes. Six physical models. Six complete sonic identities.

The engine
Annulus routes your signal through four linked processors:

Rings: a MIDI-driven polyphonic resonator based on Mutable Instruments’ Rings, running six distinct physical modeling algorithms. Eight voices spread across the stereo field with velocity and position randomization for organic variation on every hit.

Spiral: a stereo tape delay with tempo sync, ping-pong routing, wobble modulation, and saturated feedback.

Velvet: an algorithmic reverb with shimmer, diffusion, ducking, and a four-second tail.

Distortion: twelve waveshaping models at 2× oversampling, from soft tube warmth to asymmetric fuzz.

Four macro knobs: Morphe, Aigle, Nothros, Topos. Reach across the entire chain simultaneously. One gesture shapes the resonator, the delay, the reverb, and the drive at once. Topos also integrates into the visualizer’s rotation, tying the image to the physics of the sound.

Morphosis

Modal resonator — the original Rings algorithm

The filter bank that made Rings famous. Morphe adjusts the stiffness and spacing of modal partials, moving from tight harmonic clusters into rich inharmonic shimmer while the fundamental stays anchored. Stable and musical, with warm amber tones on a burnt sienna background. The classic starting point.

Sympatheia

Sympathetic strings — ensemble in a box

Six virtual strings that retune themselves in response to incoming pitch, producing the swelling unison and shimmer effect of a sympathetic string instrument. Morphe sweeps the interval relationships; Aigle controls how quickly the strings glide into tune, from instant to languid and out-of-focus. Coral and maroon over a deep purple slate, warm and restless.

Bathmos

Karplus-Strong string — from wood to metal

A plucked string model with tunable dispersion. Near center, Morphe sounds like a natural string. Push it outward and the partials spread into clangy, bell-like inharmonicity. High settings introduce a stochastic noise into the delay line that gives notes an unpredictable shimmer, like a string that isn’t quite behaving. The only mode with per-slider macro colors: red, orange, green, blue on parchment white.

Anomalia

FM voice — ratio walks

FM synthesis inside the resonator. Morphe steps through a quantized table of carrier-to-modulator ratios, moving from clean harmonic intervals through irrational, clanging relationships. Aigle pushes the modulation index — low for pure tones, high for sideband-rich noise. Every Morphe position is a different instrument: marimba, bell, metallophone, something with no name. Pale cream on deep red, minimal and stark.

Donisis

Quantized sympathetic strings — chord engine

The sympathetic string model locked to fixed chord shapes. Where Sympatheia glides freely between intervals, Donisis snaps to presets — octave, minor, major, sus4, minor 7th, major 7th, and more. Morphe steps through eleven chord voicings; the current chord name displays beside the knob. Less a texture and more a harmonic tool — play a note, choose the chord it lives inside. Cool gray-green on silver.

Antron

String and reverb — ambient string

The Karplus-Strong model with an internal reverb baked into the resonator’s tail, before the signal reaches Velvet. The result is warmer and more diffuse than Bathmos — notes bloom rather than decay cleanly. Good for pads, atmospheric textures, and anything where the line between instrument and space should blur. Copper on near-black.

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Annulus.0.1.0  ( 200 MB )

15.2 MB

Deep Evolving Pad Synth. Elysa Morph is a musical evolving pad/texture synthesizer designed for long, expressive, cinematic tones. It combines analog-style warmth, wavetable/granular detail, and spacious stereo movement in a single instrument.

Its core philosophy is simple: hide technical complexity, keep creativity immediate. Most advanced routing is intentionally under the hood, so you can shape rich sounds quickly without juggling dozens of controls. Instead of managing around 70+ parameters directly, you work through a streamlined macro workflow that stays clear, fast, and performance-ready.

Behind that minimal surface is a deep architecture with multi-engine synthesis, layered modulation, multi-stage filtering, and spatial FX. The result is an instrument that feels effortless to use, yet delivers complex, evolving sound design.

Feature Highlights:
– Dual character modes: ELYSA and WAELAR
– 3-engine architecture with deep synthesis behaviors
– 3 LFOs, 3 random modulators, and 3 ADSR envelope layers
– 3-stage filter structure for tonal sculpting and movement
– Built-in chorus/ensemble/dimension, delay, and reverb space design
– Macro-first workflow for fast, musical control
– Hidden advanced depth for complex internal motion
– 99 factory presets focused on evolving, musical pad textures

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Elysa.Morph.1.0.1  (15  MB )

15 MB

Cinematic Pad Synthesizer. Aether Drift is a cinematic pad instrument built around a simple idea: a visually elegant, macro-driven interface on the surface, with a far deeper evolving synthesis engine underneath. It is designed so the user shapes complete pad worlds, not individual technical parameters.

Rather than presenting a traditional synth panel full of oscillators, routings and modulation pages, Aether Drift hides that complexity inside the engine. The result is a workflow that stays immediate and musical, while still delivering rich, layered and evolving pad textures.

Features:
– Dual-oscillator pad body with wave morphing and unison width
– Macro-driven interface with Aether and Drift orbs for sound shaping
– Hidden layers for warmth, shimmer, harmonic glow, and evolving depth
– Integrated spatial effects including chorus, ensemble, dimension, and reverb
– Preset generation and mutation with Inspire and Evolve functions
– Visual feedback display (Vision Core) reflecting sound energy and motion
– Macro controls for tone, motion, depth, width, space, air, warmth, glow, and sparkle

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Aether.Drift.1.0.4  ( 15 MB )

199 MB

Arturia MicroBrute-based synth. Mini-Menace is a throwback to the modern resurgence of analog synths, with all sounds sourced from the Arturia MicroBrute.

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Mini-Menace.1.0.0  ( 199 MB )

4.60 MB

Droplets is a plugin that aims to recreate the old 32 bit freeware plugin Water by xoxos, a physical water droplet model synthesizer that can create individual water bubble sounds, splashes or river sounds depending on the settings. I wanted to preserve it for the foreseeable future in vst3 form and of course in 64 bit. The old version still works in FL Studio, my favourite DAW, but not for example in Ableton.

While the original’s source code is not publically available, a brief technical description of the general methods xoxos used to make it was, and with big help of the Claude Sonnet AI I was able to recreate it in JUCE relatively well. I compiled a vst3 and standalone .exe program for Windows, but the source code which is included in the download also works for Mac and Linux!

It might not have all the functions of the original and sound a little different, but can sound quite nice and simple – don’t expect it to sound realistic though!

An explanation of the controls is provided in the download as well.

The plugin is free and the source code is open, meaning you are free to do whatever you like with it, but please do not sell it for profit unaltered.

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Droplets VST  (  MB )

47.7 MB

A faithful emulation of the legendary Simmons SDSV electronic drum synthesizer. Every voice circuit has been meticulously modeled from the original hardware schematics — from the triangle oscillators and SSM2044 resonant filters to the OTA voltage-controlled amplifiers and CD4528 monostable timing circuits.

Eight drum modules — Kick, Snare, Hi-Tom, Mid-Tom, Lo-Tom, Floor Tom, Cymbal, and Hi-Hat — each with independent control over pitch, bend depth, decay, noise/tone balance, click intensity, filter cutoff, resonance, filter envelope, volume, and panning. A global drive control applies analog saturation across all modules simultaneously.

Every voice circuit modeled from the original SDSV schematics — from SSM2044 resonant filters and OTA voltage-controlled amplifiers to discrete timing circuits. Authentic analog saturation, soft VCA compression, authentic velocity dynamics, and circuit nonlinearity give HexaDrum the warmth, character, and punch of the real hardware. The result: an instrument that sounds and responds like the 1981 classic, not a digital imitation.

HexaDrum Demo

System Requirements

MAC:
macOS Ventura (13.6) or higher
(Apple silicon Macs supported)
64-bit only

PC:
Windows 10 or 11
64-bit only

MAC Users may have to confirm the use of unsigned software in their system settings for the plugin to work. Please refer to this guide on the Apple website or this YouTube tutorial.

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HexaDrum.1.0.Beta  ( 48 MB )

175.2/39.9 MB

Vital is the perfect solution for those looking to enhance their sound and unleash their creative potential. With a range of synthesis options, including wavetable and granular synthesis, Vital offers endless possibilities for sound design. The intuitive interface and powerful sound shaping controls make it easy for producers of all levels to quickly create professional-quality sounds.

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Vital.1.6.1  ( 175 MB )

299 MB

A cool retro take on a MT-600 CASIO home keyboard, jazzed it up with effects, unison, filters and more. But you can still play the original unaffected sounds if you want.

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DT-600.Mini.1.0  ( 300 MB )

94.7 MB

A synthesizer plugin emulating the Roland Juno-6, Juno-60, and Juno-106, built with JUCE.

6-voice polyphonic with dual-mode DSP (Juno-60 analog / Juno-106 firmware), per-voice analog variance, TPT ladder filter with OTA saturation, ngspice-verified BBD chorus, arpeggiator with DAW sync, portamento, and 240 factory presets (112 Juno-60 + 128 Juno-106). Parameter curves calibrated from hardware measurements, circuit simulation, and firmware analysis.

Formats: AU, VST3, LV2, CLAP, Standalone Platforms: macOS (10.15+), Windows, Linux

SysEx: Full Juno-106 SysEx support (IPR/APR send and receive). A separate AU variant (aumf) is included for Logic Pro, which blocks SysEx on standard AU instruments.

Full documentation

Ultramaster Group was born in the year 2000, in a loft in Brooklyn, NY. Our bold mission: professional-grade audio software for the Linux ecosystem. We were young, idealistic, and perhaps a little bit ahead of our time.

Life eventually pulled us into different orbits. Karl went on to found the art and design powerhouse Kayrock Screenprinting, while Dave joined the engineering teams at Google. But the music never truly stopped.

Twenty-five years ago, we were targeting the Pentium Pro, working without the luxury of oscilloscopes, service manuals, or community hubs like ModWiggler and Reddit. Today, after decades spent designing Kayrock Powertools and scaling global infrastructure, we’ve returned to the Juno source code.

A lot has changed since the late 90s. Hardware is exponentially faster and DSP methodology has evolved. We have spent time heavily recalibrating and refining the engine for the modern era. While the interface remains intentionally familiar, the internal architecture has been overhauled for better performance and precision.

We are rereleasing KR-106 as an open-source project under the GPL to give back to the community that inspired us from the start. Our goal is to make this as accurate as humanly possible, and we would love for you to help us get there.

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KR-106.2.5.12  ( 95 MB )

11.7 MB

Smoke Mono 1 is a free monophonic analog modeling synthesizer developed by Grammy-winning producer Mike Dean.

Smoke Mono 1 is a full monophonic synthesizer with no trial period, no watermarks, no limits. Yours forever.

Analog Modeling Engine
Virtual analog oscillators with saw, square, triangle, and sine waveforms. Sub oscillator with octave select. Real unison detune.

Resonant Filter
Moog-style ladder filter with cutoff, resonance, and envelope amount. Keyboard tracking. Self-oscillation at high resonance.

Bass-Preserving Distortion
Custom saturation circuit that adds grit without losing low end. From warm tape to full screaming overdrive.

Glide + Legato
Smooth portamento with adjustable glide time. Legato mode for connected phrases. Mono voice priority: last note wins.

Full ADSR Envelope
Snappy attack for plucks, slow bloom for pads. Filter envelope with separate depth control. Shape every note.

Built-In Effects
Delay synced to host tempo (1/4 note default). Reverb with freeze. Chorus for width. All built in — no extra plugins needed.

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Smoke.Mono.1.0  ( 12 MB )