---
title: Reverb
description: "A reverb as a device you can plug in: a decay, a pre-delay, a damping and a mix as a state, a panel that draws the tail with a handle, a Web Audio engine and the tools an agent drives it with."
component: true
base: base
---

<ComponentPreview styleName="base-nova" name="block-reverb" />

Puts the sound in a room. The panel draws the tail's level falling in dB from the end of the pre-delay to -60 dB: drag the handle at its end for the decay time. It is a device like the [compressor](/docs/components/compressor): a state, a panel that draws it, an engine that plays it and tools an agent calls, each its own file.

## Installation

<CodeTabs>

<TabsList>
  <TabsTrigger value="cli">CLI</TabsTrigger>
  <TabsTrigger value="manual">Manual</TabsTrigger>
</TabsList>

<TabsContent value="cli">

```bash component
npx shadcn@latest add @audio-ui/block-reverb
```

</TabsContent>

<TabsContent value="manual">

<Steps>

<Step>Install the packages:</Step>

```bash
npm install @audio-ui/react @audio-ui/core
```

<Step>Add the pieces you want. All of them, or only the state and the panel if your engine is elsewhere:</Step>

```bash
npx shadcn@latest add @audio-ui/reverb-device @audio-ui/reverb-panel @audio-ui/reverb-engine
```

<Step>Copy and paste the demo that wires them, if you want it.</Step>

<ComponentSource
  styleName="base-nova"
  name="block-reverb"
  title="components/examples/block-reverb.tsx"
/>

</Steps>

</TabsContent>

</CodeTabs>

## Usage

```tsx
import { ReverbPanel } from "@/components/audio-ui/devices/reverb/panel";
import { reverbDevice } from "@/components/audio-ui/devices/reverb/device";

const [state, setState] = useState(() => reverbDevice.defaults());

<ReverbPanel onValueChange={setState} value={state} />;
```

The state is a plain object keyed by parameter id, so a host stores it, saves it with its project and sends it where it likes. `reverbImpulse(sampleRate, state)` makes the impulse response of a room, and `reverbDecay(state)` the decay the panel draws.

## The engine

```ts
import { createReverbEngine } from "@/components/audio-ui/devices/reverb/engine";

const engine = createReverbEngine(ctx, state);
source.connect(engine.input);
engine.output.connect(ctx.destination);
engine.update(nextState); // parameters ramp: no click
engine.dispose();
```

The room is a convolver fed an impulse response made from the decay and the damping. A convolver cannot change its impulse without a click, so the engine has two and cross-fades: a new room is built in the idle one, at most every 120 ms while a knob moves.

## The tools

```ts
import { deviceTools } from "@audio-ui/core/device";
import { reverbDevice } from "@/components/audio-ui/devices/reverb/device";

const [set, reset] = deviceTools(reverbDevice);
```

`set` and `reset` change the state, with the ranges the device enforces: a value out of range is brought in and reported, a wrong one is refused by name, and a call never throws.

## Accessibility

Every control is a native input: the knobs are sliders named after their parameter, with the value and unit as the text value, the switch is a toggle button, and everything takes the keyboard.