How to disable airpods microphone

Hi guys!

I am a happy user of recording apps such as Voice Notes from Apple or Dictaphone.

I tend to use it with cord earphones, to record without earphones and hear the recording with the earphones. 

However, I recently acquired Apple AirPods and I would like to record with the phone microphone (while wearing the AirPods) and hear the recording through the AirPods. However, this is not possible because Dictaphone is using the AirPods mic instead of the phone´s mic. 

Do you know how to solve this?

Ideally I would like to:

1. Always record through the iPhone mic

+

2. Always hear the recording through the AirPods

My phone is an iPhone 7+ running iOS 12, by the way. 

Thanks in advance for your help.