> ## Documentation Index
> Fetch the complete documentation index at: https://docs.daily.co/llms.txt
> Use this file to discover all available pages before exploring further.

# startLocalAudioLevelObserver()

> Starts polling the local microphone audio level at a specified interval.

`startLocalAudioLevelObserver(interval?)`

<Badge color="green">{"✓"} Prebuilt</Badge> <Badge color="green">{"✓"} Custom</Badge>

Once started, a [`local-audio-level`](/reference/daily-js/events/media-events#local-audio-level) event is emitted at the specified interval. Use [`getLocalAudioLevel()`](/reference/daily-js/instance-methods/get-local-audio-level) to read the current value synchronously.

## Parameters

<ParamField body="interval" type="number" default="100">
  How often to emit `local-audio-level` events, in milliseconds. Minimum is 100ms. Defaults to 100ms if not specified.
</ParamField>

## Return value

Returns a `Promise<void>` that resolves when the observer is running.

## Example

```javascript theme={null}
// Emit audio level events every 500ms
await call.startLocalAudioLevelObserver(500);

call.on('local-audio-level', ({ audioLevel }) => {
  console.log('Local audio level:', audioLevel);
});

// Stop when done
call.stopLocalAudioLevelObserver();
```

## See also

<CardGroup>
  <Card title="Methods" icon="code" iconType="solid">
    * [stopLocalAudioLevelObserver()](/reference/daily-js/instance-methods/stop-local-audio-level-observer)
    * [isLocalAudioLevelObserverRunning()](/reference/daily-js/instance-methods/is-local-audio-level-observer-running)
    * [getLocalAudioLevel()](/reference/daily-js/instance-methods/get-local-audio-level)
    * [startRemoteParticipantsAudioLevelObserver()](/reference/daily-js/instance-methods/start-remote-participants-audio-level-observer)
  </Card>

  <Card title="Events" icon="bolt" iconType="solid">
    * [local-audio-level](/reference/daily-js/events/media-events#local-audio-level)
  </Card>

  <Card title="Guides" icon="book-open" iconType="solid">
    * [Audio and video](/docs/daily-js/guides/audio-video)
  </Card>
</CardGroup>