# 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 [#understand-the-tech-2]

    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 [#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 [#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 [#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 [#reference-2]

    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 [#api-reference-2]

    * [`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)