DuskVerb

DuskVerb is a free algorithmic reverb that covers everything from tight rooms to infinite ambient washes. Five algorithms, 25 presets, and enough control to dial in exactly the space you need.

Overview

At its core, DuskVerb uses a 16-channel Hadamard feedback delay network to build dense, natural-sounding reverb tails. Each algorithm has its own carefully tuned delay structure, and the Dattorro-inspired diffusion stages smooth everything into a lush, coherent wash. The early reflections are physically modeled with air absorption, so small spaces actually sound like small spaces.

Algorithms

Each algorithm has its own delay line configuration and default character. They’re not just preset tweaks - the underlying topology changes.

Plate is dense, smooth, and bright. No early reflections, just pure diffuse tail. The classic studio vocal reverb. Works great on snare and mix bus too.

Hall is the all-purpose workhorse. Natural concert hall sound with spacious depth, strong early reflections, and balanced frequency response. If you only use one algorithm, this is probably it.

Chamber sits between Hall and Room. Warm and intimate, with a slightly brighter treble response that helps things cut through. Good for strings, piano, and acoustic instruments.

Room is tight and realistic. The early reflections are prominent, giving you a clear sense of physical space, while the late decay stays short and clean. Great for drums, dialog, and anything that needs natural ambience without a long tail.

Ambient goes big. Ethereal washes, long decay times, heavy modulation, and no early reflections. This is your pad reverb, your drone reverb, your cinematic effects reverb.

Controls

The top row handles the big picture: Decay sets the tail length (0.2s up to 30s), Pre-Delay adds a gap before the reverb starts (with optional tempo sync), and Size scales the virtual room dimensions. Hit Freeze to sustain the current tail indefinitely while muting new input.

The Character section shapes the tone. Diffusion controls how dense the tail is. Bass Multiply and Treble Multiply let you independently adjust how long the lows and highs sustain relative to the overall decay time. Crossover sets the frequency split between the two bands.

Modulation adds movement to the tail. A little goes a long way for keeping things sounding natural and avoiding metallic artifacts. Crank it for chorus-like shimmer effects.

The Output section has your Mix knob, Width control (0-200%), and Lo Cut / Hi Cut filters for shaping the reverb’s frequency range. Bus Mode sets the mix to 100% wet for send/return setups.

Factory Presets

DuskVerb ships with 25 presets across 9 categories. You can also save, load, and delete your own presets from the menu.

• Vocals: Vocal Plate, Vocal Hall, Vocal Room
• Drums: Drum Room, Drum Plate, Drum Ambient
• Guitar: Guitar Spring, Guitar Hall
• Keys: Keys Chamber, Synth Pad
• Mix: Mix Glue, Mix Space
• Rooms: Small Room, Medium Room, Large Hall
• Plates: Short Plate, Long Plate
• Ambient: Infinite Pad, Dark Cloud, Shimmer Space, Cathedral
• Special: Slap Back, Gated Verb, Lo-Fi Verb, Wide Stereo

Under the Hood

For the curious: the FDN uses a 16x16 Hadamard mixing matrix with per-channel two-band damping filters. Input diffusion is a 4-stage Dattorro allpass cascade, and there’s an additional 2-stage modulated output diffuser. Early reflections use 16 multi-tap delays per channel with exponential time distribution and air absorption modeling. Delay reads use cubic Hermite interpolation, and all parameters are smoothed per-sample to avoid automation artifacts.

DAW Compatibility

Tested in Logic Pro (AU), Reaper (VST3/LV2), and Ardour (LV2). Should also work in Bitwig, Studio One, FL Studio, Ableton Live, Cubase, and GarageBand.

Installation

Linux

VST3: ~/.vst3/DuskVerb.vst3
LV2:  ~/.lv2/DuskVerb.lv2

Windows

VST3: C:\Program Files\Common Files\VST3\DuskVerb.vst3

macOS

VST3: ~/Library/Audio/Plug-Ins/VST3/DuskVerb.vst3
AU:   ~/Library/Audio/Plug-Ins/Components/DuskVerb.component

Open Source

DuskVerb is open source under GPL-2.0. View the source, report issues, or contribute on GitHub.