It isn't possible to make a lag free mic on Android yet, but it's good enough for emergency use.
How to use:
1. Connect your device to an external speaker, and speak in front of the internal microphone
2. Use a deconcentrator/an adapter (e.g. iRig), connect an external speaker and microphone
It is suitable for:
1. Music Performance
3. Outdoor Activity
4. Audio Amplification