DuskVerb

DuskVerb is a free algorithmic reverb that gives you eleven genuinely different DSP engines under the same UI, separate topologies you can audition like swapping hardware boxes, not flavors of the same algorithm. 20 factory presets inspired by real studio gear, a large DECAY visualization, Tone / Character / Duck macro shapers, and the controls you need to shape anything from a tight slap to an infinite shimmering pad.

Overview

Start with the engine. Each one is a completely different reverb, so choosing an engine feels less like turning a knob and more like swapping the box in your rack. Find a space you like, then shape it: size, decay, modulation, damping, early reflections, and a handful of output filters are all a drag away. Every factory preset is ready to sit in a mix the moment you load it, but nothing is locked down. Drop the same preset onto a different engine and you land somewhere new.

Switching engines never clicks or drops out. All eleven are warmed up and running under the hood, so you can flip between them while the music keeps playing and hear each space take over in real time. And because the modulation wanders instead of cycling on a fixed sine, the tails shimmer and breathe like high-end hardware rather than wobbling in a loop.

New in v0.6.0: a Tone, Character, and Duck macro row for quick global moves, two dedicated hall engines (Hall and Dense Hall) with honest decay times, and new Reverse and Tiled Room engines. The preset menu is now a clean two-column layout with in-window dropdowns that behave correctly under Wayland and XWayland.

Engines

Plate is a 2-allpass cross-coupled tank built on the Dattorro 1997 plate topology. Bright, dense, smooth. The classic studio vocal plate sound. Use it on snares, vocals, the mix bus. Presets: Vocal Plate, Drum Plate.

Vintage Plate is the same plate tank with a fixed post-EQ voicing dialed in for warmer, vintage-hardware character. Presets: Vintage Vocal Plate, Vintage Gold Plate.

Smooth Plate is a 6-allpass density cascade tank. It diffuses the input fast and produces lush, dense ambience and smooth pads. Lower size settings give you intimate spaces; higher settings open up to larger, denser tails.

Chamber uses four cross-coupled tanks with 48 total taps. Designed for realistic chambers and rooms with strong early reflections and clean late decay. Great for drums, dialog, and anything where you want a sense of physical space without a long tail. Presets: 79 Vocal Chamber, Large Chamber.

Spring is a 3-spring tank with a dispersion allpass chirp, inspired by the Fender 6G15. Boingy, characterful, perfect for guitar amps, surf textures, and anywhere a hardware spring’s “drip” character is the sound. Preset: Surf ‘63 Spring.

Gated is a 64-tap feed-forward delay line with envelope shaping, in the spirit of the AMS RMX16 non-linear programs. Big-room reverb shaped by the dry signal’s transients, the room blooms in for the snare hit, then cuts off cleanly. The iconic Phil Collins / Hugh Padgham gated-snare sound. Preset: 1981 Gated Snare.

Shimmer is an 8-channel Hadamard FDN with a granular pitch shifter in the feedback loop, in the spirit of Brian Eno and Daniel Lanois’s 1980s outboard rig and Valhalla Shimmer. Octave-up shimmer reverbs for ambient pads, sustained guitars, drone work. Overhauled in v0.6.0 with a post-loop HF air voice and down-octave lows. Presets: Black Hole, Deep Blue Day.

Reverse is a causal rising-gain early-reflection onset feeding a dark modulated FDN tail, in the spirit of the Lexicon PCM Room reverse programs. The tail swells up into the transient instead of decaying away from it. Use it for risers, pads, vocal throws, and vintage tape-reverse effects. Preset: Reverse Taps.

Hall is a feedback delay network with a per-octave graphic EQ in the feedback loop, giving independent per-band RT60 for honest decay and smooth, non-metallic tails. New in v0.6.0. Select it on any preset when you want the most truthful per-band decay control.

Tiled Room front-loads a sparse tapped-delay early-reflection field welded to a short, dark FDN tail. New in v0.6.0, it nails the tight, bright-then-dark character of a ceramic tiled room that a single-tank FDN cannot express. Preset: Tiled Room.

Dense Hall is a heavily diffused 8-line FDN with allpass diffusion and modulation at every stage, giving a dense, smooth tail that the standard hall FDN structurally cannot reach. New in v0.6.0, for thick, lush concert spaces. It powers all four factory hall presets: Bright Hall, Vocal Hall, Cathedral Large Hall, Blade Runner 224.

Macros

New in v0.6.0, three macro shapers sit in the MACRO row and layer on top of every preset’s baked values for fast global voicing without diving into individual knobs.

Tone is a spectral tilt from dark to bright in a single move (drives Treble Mult and Hi Cut together).

Character adds movement and grit, blending in extra modulation depth and saturation as you turn it up.

Duck ducks the wet tail while the dry input is loud, then lets it swell back as the source decays, sidechained off the dry signal to keep vocals and busy mixes clear.

Controls

DECAY is a large concentric-ring readout. Drag vertically. Sets RT60 from 0.2 s to 30 s. Recalibrated in v0.6.0 for honest decay times across all factory presets.

Pre-Delay is the gap before the reverb starts (with tempo sync). Use a short 18 ms for vintage vocals, longer for modern pop spaces.

Size sets virtual room dimensions. Affects echo density and spacing.

Depth / Rate are modulation amount and speed. A little goes a long way for keeping the tail sounding natural and avoiding metallic resonances.

Treble Mult / Bass Mult / Crossover are independent decay multipliers for the highs and lows, with an adjustable crossover frequency. Below 1x treble gives natural air absorption; above 1x bass makes bass ring longer than mids.

Diffusion controls input smearing. Low gives grainy slap-back echoes; high gives a smooth wash.

ER Level / ER Size set early reflection level and spacing. The early reflections define the perceived room shape.

Lo Cut / Hi Cut are wet-signal filters.

Width sets stereo width from 0 to 200%.

Mono < sums the wet signal to mono below the cutoff. Use 80 to 150 Hz to keep low-end tight on busy mixes; 20 Hz bypasses it.

Trim is an output gain offset.

Freeze mutes input and loops the existing tail indefinitely. Useful for ambient pads, risers, and effects.

Bus Mode outputs 100% wet regardless of DRY/WET. Use on a send/return aux.

Factory Presets (20)

Plates Vocal Plate, Vintage Vocal Plate, Drum Plate, Vintage Gold Plate Springs Surf ‘63 Spring Halls Bright Hall, Vocal Hall, Cathedral Large Hall, Blade Runner 224 Chambers 79 Vocal Chamber, Large Chamber Rooms Small Drum Room, Medium Drum Room, Live Room, Tiled Room, Ambience, 1981 Gated Snare, Reverse Taps Shimmer Black Hole, Deep Blue Day

Each preset is voiced against a recognizable hardware reference (Lexicon 224, EMT 140 plate, AMS RMX16 non-lin drum, Bricasti M7 cathedral, Eventide Blackhole infinite, Valhalla Shimmer BlackHole / DeepBlueDay). In v0.6.0 the hall presets migrated to the new Dense Hall engine for honest RT60, and the whole library was retuned against Lexicon, Valhalla, and EMT hardware anchors. The UI’s accent color shifts to match the active engine, so you always know which architecture you’re hearing. The preset menu is a scannable two-column layout with in-window dropdowns.

You can also save, load, and delete your own presets from the menu. They live in ~/Library/Application Support/Dusk Audio/DuskVerb/Presets/ (macOS) and the equivalent locations on Linux/Windows.

Under the Hood

Every engine ships with three-band damping (low-shelf + high-shelf 2nd-order RBJ biquads in a serial cascade). All delay reads use cubic Hermite interpolation. Parameters smooth per-sample to avoid automation zipper noise. Modulation is generated by a smoothstep-interpolated random-walk LFO, normalized to a consistent 16-sample excursion across the engines. The Hall engine fronts a 16-channel Hadamard FDN with a per-octave graphic EQ in the feedback loop for independent per-band RT60; Dense Hall uses a heavily diffused 8-line FDN; Tiled Room welds a sparse tapped-ER front to a short, dark 4-line FDN tail; Chamber cross-couples four allpass tanks with prime-spaced delay lines; the Smooth Plate density cascade uses six series allpasses; the Shimmer engine wraps a granular pitch shifter around an 8-channel Hadamard FDN with a feedback delay decoupled from the host block size, plus a post-loop HF air voice and down-octave lows. Audio thread is allocation-free and lock-free; engine switching only flips a pointer.

DuskVerb is sample-rate independent. All base delay lengths and modulation excursions are tuned at 44.1 kHz and scale linearly with the host sample rate. Tested at 44.1 / 48 / 96 / 192 kHz.

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.