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

# Keep Microphone Warm

> Reduce push-to-talk startup delay by keeping your microphone session open between recordings.

When you trigger push-to-talk, there is a brief moment while your operating system initializes the microphone capture path. On most wired or built-in microphones this delay is imperceptible, but on Bluetooth devices it can be long enough to clip the first word or two of your dictation.

**Keep microphone warm** eliminates that delay by holding a silent, idle audio session open between recordings so the hardware is ready the instant you press your shortcut.

## How it works

When the setting is on, HyperWhisper opens a low-level capture session immediately after each recording ends and keeps it open until the next one begins. No audio from this idle session is stored, processed, or sent anywhere — the captured buffers are discarded as soon as they arrive. The session closes automatically while a real recording is running and reopens once recording stops.

## Enabling the setting

<Tabs>
  <Tab title="macOS">
    Open **Settings → Sound** and turn on **Keep microphone warm between recordings**.

    The change takes effect immediately — no restart required.
  </Tab>

  <Tab title="Windows">
    Open **Settings → Sound** and check **Keep microphone warm**.

    The change takes effect immediately — no restart required.
  </Tab>
</Tabs>

## Trade-offs to be aware of

<Tabs>
  <Tab title="macOS">
    <Warning>
      While **Keep microphone warm** is on, macOS displays the **orange microphone indicator** in the menu bar continuously — even when you are not recording. This is expected behavior: macOS shows the indicator whenever any app holds a capture session open.

      Additionally, Bluetooth headsets may stay in their lower-quality **call audio profile** rather than switching back to stereo mode between recordings. If audio quality from your headset matters outside of HyperWhisper (for example, during music playback), consider leaving this setting off.
    </Warning>

    Turn the setting off if:

    * You want the orange mic indicator to appear only during actual recordings.
    * You use Bluetooth headphones and prefer stereo quality between recordings.
    * You are on battery and want to minimize background activity.
  </Tab>

  <Tab title="Windows">
    There is no system-level recording indicator on Windows for the idle session.

    The idle stream runs at 16 kHz mono and consumes minimal CPU and battery — the effect is small but non-zero. Turn the setting off if power consumption is a concern.
  </Tab>
</Tabs>

## Platform notes

<Tabs>
  <Tab title="macOS">
    * The idle session uses `AVCaptureSession` with `AVCaptureAudioDataOutput`. All sample buffers are discarded immediately.
    * HyperWhisper reuses your existing device selection — if you have a specific microphone chosen in **Settings → Sound**, the warm session runs on that device.
    * If you switch input devices while the setting is on, HyperWhisper automatically restarts the idle session on the new device.
    * The session does not start if microphone permission has not been granted.
  </Tab>

  <Tab title="Windows">
    * The idle stream uses NAudio `WaveInEvent` at 16 kHz, 16-bit mono.
    * All captured audio buffers are discarded without processing.
    * If the device changes, HyperWhisper restarts the idle stream on the new device automatically.
    * The stream does not start if the selected device is unavailable.
  </Tab>

  <Tab title="iOS">
    Keep microphone warm is not available on iOS.
  </Tab>
</Tabs>