# Device management (/en/realtime-media/voice/build/control-audio-and-devices/set-audio-route/web)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

Voice SDK provides APIs for managing input and output devices. Use these APIs to switch devices dynamically during Voice Calling and implement hot-swap logic when devices are added or removed.

## Understand the tech

Managing audio devices involves selecting, switching, and handling changes in media input and output devices. The Voice SDK provides APIs to:

* Change the default audio output route to a selected device.
* List available microphones.
* Dynamically switch devices during Voice Calling.
* Detect device changes (added or removed) and enable hot-swapping.

### Change the default audio route

To change the audio output device, retrieve a list of available media devices, filter for audio output devices, and select the desired `deviceId`.

```js
// Request a list of media devices and filter audio output devices.
const devices = await navigator.mediaDevices.enumerateDevices();
const audioOutputs = devices.filter(device => device.kind == "audiooutput");

const audioContext = new AudioContext();

// Pick the first available audio output.
const deviceId = audioOutputs[0].deviceId;
await audioContext.setSinkId(deviceId)
```

For further details on changing the default audio route, see [Change the destination output device in Web Audio](https://developer.chrome.com/blog/audiocontext-setsinkid).

### Change the audio capture device

To set an audio capture device, retrieve available microphones using `AgoraRTC.getMicrophones()`. Then, call `setDevice(deviceId)` with the desired `deviceId` to use the selected capture device.

```js
// Get available microphones
const microphones = await AgoraRTC.getMicrophones();

if (!microphones.length) {
 console.error("No microphone found");
 return;
}

// Switch to the first available microphone
localAudioTrack.setDevice(microphones[0].deviceId );
```

Here `localAudioTrack` refers to the local audio track created using `AgoraRTC.createMicrophoneAudioTrack`.

<CalloutContainer type="info">
  <CalloutDescription>
    You can call `setDevice` to change the capture device even after publishing a track. However, on certain mobile devices, this operation may fail due to hardware or browser limitations.
  </CalloutDescription>
</CalloutContainer>

## Hot-swap capture devices

Voice SDK provides the `onMicrophoneChanged` callback to detect changes in the plug-in status of audio device. To switch to a newly connected device automatically, implement a listener for this callback and call `setDevice` to use the new device

```javascript
AgoraRTC.onMicrophoneChanged = async (changedDevice) => {
 // When a new device is detected, switch to the new device
 if (changedDevice.state === "ACTIVE") {
  microphoneTrack.setDevice(changedDevice.device.deviceId);
 } else if (changedDevice.device.label === microphoneTrack.getTrackLabel()) {
  // Switch to an existing device when the unplugged device is the current device
  const oldMicrophones = await AgoraRTC.getMicrophones();
  oldMicrophones[0] && microphoneTrack.setDevice(oldMicrophones[0].deviceId);
 }
};
```

<CalloutContainer type="warning">
  <CalloutDescription>
    If the user adds a virtual or a faulty device, hot-swap routing logic may result in no picture or no sound when the device is plugged-in or unplugged.
  </CalloutDescription>
</CalloutContainer>

## Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

### API reference

* [`setDevice`](https://api-ref.agora.io/en/video-sdk/web/4.x/interfaces/imicrophoneaudiotrack.html#setdevice)

* [`onMicrophoneChanged`](https://api-ref.agora.io/en/video-sdk/web/4.x/interfaces/iagorartc.html#onmicrophonechanged)