Shu
Seven reverbs. One focused interface.
Free. No license required. macOS 11.5+ · Windows 10+ · Linux
A reverb plugin offering seven distinct algorithms, a tempo-synced predelay with feedback, a parallel reverse-delay path, and a freeze function, designed to cover the full range of spatial processing, from transparent natural ambience to overt creative effect, in one focused interface.
Seven Modes
Each mode is a completely different algorithm. Crossfade between them mid-playback without clicks.
Silk
Smooth, dense, refined wash
Reach for it when you want a clean, modern reverb that disappears into the mix. The flagship sound.
Features
Everything you need to place a sound in space.
Seven Reverb Algorithms
Silk, Drift, Plate, Classic, Slap, Spring, and Ether. Each is a completely different character, from transparent ambience to overt creative effect. Crossfaded switching means you can audition modes mid-playback without clicks.
Download Shu
Free. No license activation. No account.
VST3, AU, and CLAP installed together.
macOS
- macOS 11.5 or later
- Intel or Apple Silicon
- VST3, AU, CLAP
Windows
- Windows 10 or later
- 64-bit
- VST3, CLAP
Linux
- 64-bit distro
- x86_64
- VST3, CLAP
If Shu finds a place in your work, donations are welcome.
Manual
Complete reference for every control in Shu.
Quick Start
- Drop Shu on a track in your DAW.
- The default mode is Silk, a clean, dense reverb good on almost anything.
- Turn the Mix knob to taste. 50% is the starting point; lower for subtle ambience, higher for big washes.
- Reach for Decay to make the tail longer or shorter.
- If it sounds too bright or boomy, use Damp to darken the tail, and Low Cut / High Cut to clean up the wet signal.
That's it. Everything else is for flavor.
The Interface at a Glance
Top Row
The predelay (or reverse-delay) cluster on the left, followed by the core reverb controls:
[Predelay] [Damp] [Decay] [Mix]Bottom Row
The wet-signal filters on the left, and two mode-specific knobs on the right that change label when you switch reverb mode:
[Low Cut] [High Cut] [Mode Knob 1] [Mode Knob 2]Between the two rows, dead-center, is the Freeze button (a snowflake).
Above the knobs sits a row of seven mode buttons: Silk, Drift, Plate, Classic, Slap, Spring, Ether.
At the very top is the Power switch (center), the Shu logo (left), and the Mikey Audio logo (right). Clicking either logo flips the panel over to the back view, which shows a description of the currently selected mode.
A couple of small tucked-away controls live near the Predelay knob: the feedback amount (a tiny circle on the left), a flame icon for saturation, a clock-face icon on the right for tempo sync, and a small double-arrow icon below the knob that switches between Predelay view and Reverse Delay view (it glows green when reverse view is active).
The Main Knobs
These five knobs are always visible regardless of which mode you choose.
Mix
Range: 0% – 100%Default: 50%The wet/dry balance. 0% = pure dry, 100% = pure wet. On an insert, set to taste. On an aux/send, set to 100% and control reverb amount with the send level on each contributing channel.
Note: Even at Mix = 0%, the reverse-delay path can still be heard if you have Reverse Blend turned up; that path is mixed into the dry side.
Decay
Range: 0% – 100%Default: 50%How long the reverb tail lasts. Low = short tight ambience; high = long sustained tails. Exact length depends on the mode. Combine with Freeze for infinite sustain.
Damp
Range: 0% – 100%Default: 0%Darkens long tails by progressively shaving off high frequencies the further the tail decays. Think tiled bathroom (no damping) vs. heavily curtained room (lots of damping).
Low Cut
Range: 20 Hz – 300 HzDefault: 300 HzA highpass filter on the wet signal only. Clears low-end mud from the reverb without touching your dry sound. Push it up if reverb feels boomy; pull down toward 20 Hz if it feels thin.
High Cut
Range: 2 kHz – 20 kHzDefault: 20 kHzA lowpass filter on the wet signal. Low values give a dark, vintage 'old hall' feel; high values give an open, modern, full-range sound. Excellent for taming metallic ring on bright modes.
Choosing a Reverb Mode
The seven mode buttons across the top select the reverb algorithm. Switching is seamless: Shu crossfades smoothly so you can audition modes without clicks. Each mode has a completely different character.
| Mode | Character |
|---|---|
| Silk | Smooth, dense, refined wash |
| Drift | Spacious, always-moving, never-static |
| Plate | Glassy, classic studio plate |
| Classic | Bright, recognizably 'reverby' |
| Slap | Tight, punchy, room-like |
| Spring | Boingy, chirpy, dub-style spring tank |
| Ether | Pitch-shifted shimmer cascade |
Tip: what you hear depends as much on the source as on the settings. Transient material (drums, plucked guitar) brings out Spring's chirp, Slap's short room, and diffusion bite. Sustained material (pads, strings, vocals) reveals Silk and Drift's modulation, Damp's progressive rolloff, and Ether's Shine cascade. If a setting seems flat, try the opposite kind of source.
All mode knobs range from 0% to 100%. Most default to 50% (neutral). Silk and Drift Mod Depth default to 0% (no modulation); Classic Width and Ether Rain/Shine default to 100% (full effect); Slap Size defaults to 50%.
Predelay
A delay applied to the wet signal only, before it hits the reverb. Useful for separating the dry instrument from its reverb tail (so the dry attack stays clear) or for creating a rhythmic echo before the reverb blooms.
Predelay Time
Range: 0 ms – 500 ms · Default: 0 ms
20–40 ms is common for separating a vocal from its reverb without sounding like an echo. 100 ms+ starts to sound like a distinct slapback before the tail.
Tempo Sync (Clock Icon)
A small clock-face icon to the right of the Predelay knob toggles tempo sync. When it's lit, the knob switches from milliseconds to a musical division like 1/4 or 1/8 and locks to your DAW's tempo.
Feedback (FB)
Range: 0% – 100% · Default: 0%
A small circle to the left of the Predelay knob. Turns the predelay into a delay/echo by feeding the delayed signal back into itself. Drag vertically to set the amount.
Saturation (SAT)
A small flame icon. Off (default) is a transparent limiter that keeps the loop from running away. On (glows red) is a soft tanh saturator that warms the feedback loop, adding gentle compression and analog character. Worth turning on whenever you push the feedback high.
Reverse Delay
A completely separate delay path that reads its buffer backwards. Every chunk of audio plays in reverse before being mixed in. The leading edge of each reversed chunk is softened with a short fade-in envelope so you get smooth onsets rather than clicks. It runs in parallel with the predelay; both are active in the DSP at the same time. You only see one cluster at a time on the UI; flipping between them is purely cosmetic.
Switching to Reverse View
Below the Predelay knob is a small double-arrow icon. Click it to switch the top-row left cluster from Predelay to Reverse Delay; the icon glows green while reverse view is active. The REV toggle itself doesn't enable or disable anything; both paths are always running. It only controls which one you can edit on screen.
Reverse Delay Time
Range: 0 ms – 2000 ms · Default: 400 ms
Sets the length of the reverse chunk. Longer windows mean each reversed segment is longer (more drawn-out); shorter windows give choppier, more rhythmic reverse stutter.
Reverse Feedback (FB) & Saturation (SAT)
Same behavior as the predelay's FB and SAT controls but on the reverse-delay loop. Push FB high and turn on SAT to keep the loop warm and controlled. The result is a dense, cascading wash you can't get from a forward reverb.
Reverse Blend
Range: 0% – 100% · Default: 0%
The most important reverse-delay control. Sets how much of the reverse signal is actually mixed into your output. When you turn Blend up, the reversed signal is added to both the reverb input and the dry path. The reverb engine sees the reversed signal too, so your reverb tails build on the reversed sound. The reversed signal is also audible at Mix = 0%, letting you use the reverse delay as a stand-alone effect.
Tip: for a reverse-delay-only effect (no reverb), set Mix to 0%, choose any mode, and just turn up Blend. Perfect for guitar leads.
Freeze
The snowflake button in the dead center of the panel, between the two rows of knobs.
Click it and the current reverb tail is frozen, pinned at near-infinite decay. The reverb sustains forever, and the input is muted so new audio doesn't add to the frozen wash. It glows cyan when active.
Click it again to release. The tail then decays normally.
Try it on sustained chords, vocal phrases, drone material. Or set up an automation lane to capture a single hit and let it sustain.
The predelay and reverse-delay buffers keep filling normally while freeze is on, so when you release it, the live signal resumes cleanly.
Power and Preserve Tail
Power
The horizontal slide switch at the top center of the panel is Shu's master on/off. On (right) routes audio through the reverb. Off (left) passes audio through dry, no processing.
Tail (back panel)
Duplicated on the back of the panel (click either logo to flip) as Tail. Tail controls what happens when you turn Power off:
- Tail off (default): turning Power off instantly mutes the reverb tail. Audio passes through dry immediately.
- Tail on: turning Power off lets the existing tail ring out naturally before going silent. New input stops triggering the reverb, but anything already in the tail finishes decaying.
Useful for live performance: automate Power to mute a reverb wash without cutting its tail abruptly.
Tempo Sync
Both the Predelay and the Reverse Delay can sync to your DAW's tempo. Click the clock-face icon next to either time knob to enable sync. When sync is on, the time knob changes from milliseconds to a musical division. Predelay and Reverse Delay sync independently. You can put one on a 1/8 note and leave the other in free time.
Available Divisions
Default: 1/4. Try Predelay on 1/16D and Reverse Delay on 1/4 for a busy, off-beat texture; or both on 1/4 for a more locked-in groove.
Free, Forever
No trial, no account, no upgrade tier. Just the plugin.
If Shu finds a place in your work, donations are welcome.