---
title: Delay
description: "A delay as a device you can plug in: a time, a feedback, a tone and a mix as a state, a panel that draws the echoes 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-delay" />

Repeats the sound. The panel draws the echoes the state makes, one line each, fainter as they fade: drag the handle on the first one across for the time and up for the feedback. 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-delay
```

</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/delay-device @audio-ui/delay-panel @audio-ui/delay-engine
```

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

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

</Steps>

</TabsContent>

</CodeTabs>

## Usage

```tsx
import { DelayPanel } from "@/components/audio-ui/devices/delay/panel";
import { delayDevice } from "@/components/audio-ui/devices/delay/device";

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

<DelayPanel 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. `delayTaps(state, windowMs)` returns the echoes a state makes, which is what the panel draws.

## The engine

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

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

The repeats go round a low-pass tone filter, so each is darker than the one before. A change of time glides slowly, so the echo bends like a tape instead of clicking, and the feedback stops short of 95 % so it cannot run away.

## Synced to the tempo

Switch **Sync** on and the time is a note value instead of milliseconds: `1/8`, a triplet `1/8t`, a dotted `1/8d`, from 1/32 to a whole note, read against the host's tempo. The tempo is the host's, not the delay's: give it to the engine with the first state or with any update.

```ts
const engine = createDelayEngine(ctx, state, { tempo }); // { bpm: 100, beatsPerBar: 4, beatUnit: 4 }
engine.update(nextState, { tempo: { ...tempo, bpm: 120 } }); // the echo follows
engine.update(otherState); // no context: the last tempo holds
```

The panel takes the same tempo as a prop, `tempo`, and draws the echoes where the notes fall. With Sync on, the handle lands on the nearest note value and the time knob is drawn off; with it off, the note list is. A note longer than the delay can hold (two seconds) is held to that. The tempo does not come from an agent's tool call: `delay_set` can switch Sync on and pick a note, and the host decides the tempo it is read against. The `1/8d` the block starts on is a dotted eighth at the loop's 100 BPM, 450 ms.

## The tools

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

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

`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.