iOS doesn't offer a direct way to show which mic is active. How did you test it? You haven't mentioned which model of AirPods you're using. There have been significant changes to the AirPods lineup over the past four years.

The recording quality will also depend on the specific model of AirPods you have. For example:
- AirPods Pro (1st & 2nd gen) with active noise cancellation can capture your voice more clearly and filter out environmental sounds.
- AirPods (3rd gen) and AirPods Max also benefit from noise isolation, but their noise-canceling features are not as robust as the Pro models.

The Voice Memo app on iPhones primarily uses the built-in microphone of the device for recording.
However, there might be specific scenarios where the app could utilize the AirPods' microphone:
- Headphone Mode: If you're using AirPods while recording, the app might default to using the AirPods' microphone for better audio quality and reduced background noise.
- Hands-free Recording: If you're recording with your iPhone in your pocket or bag, using the AirPods' microphone would be the only practical option.
In summary: While the built-in microphone is the default and primary source, the Voice Memo app can intelligently switch to the AirPods' microphone when it's more suitable for optimal recording quality and convenience.

To test which mic is being used, try the following it is not as simple as you think it its.
To determine whether your iPhone's Voice Memos app is using the device microphone or your AirPods microphone, you can perform a simple test:
1. Start a Recording:
- Open the Voice Memos app on your iPhone.
- Tap the red record button to begin recording.
2. Speak into Different Microphones:
- Speak directly into the bottom of your iPhone: This will test the device's built-in microphone.
- Speak into your AirPods: This will test the AirPods' microphone.
3. Stop and Listen:
- Tap the red stop button to end the recording.
- Play back the recording.
4. Analyze the Audio:
- Clarity: Compare the clarity of your voice in each scenario. If your voice sounds clearer when speaking into the AirPods, they are likely being used as the primary microphone.
- Background Noise: Pay attention to any background noise captured in the recording. If you hear more background noise when using the AirPods, it might indicate that the iPhone's microphone is picking up more ambient sound.
Additional Tips:
- Check AirPods Connection: Ensure your AirPods are properly connected to your iPhone before starting the test.
- Test in Different Environments: Try the test in various environments (quiet room, noisy environment) to see how the microphone selection affects audio quality in different situations.
- Review AirPods Settings: In the Bluetooth settings on your iPhone, you can check if your AirPods are set to automatically connect for audio. This can help ensure they are prioritized for audio input.
By following these steps, you can effectively determine which microphone (device or AirPods) is being used by the Voice Memos app on your iPhone.