Technically + Logically, Why apps use 3rd or 4th mic for recording on Lumia 930 but not 1st or 2nd?

[FAHMI BASSEM]

Got a used Lumia 930 from a friend, everything works fine except for the mics (3 + 4) -confirmed by using Lumia Phone test-, gone through multiple forums, still don't know if it's HD or SW thing :\

Any way, Why apps + SkeakerPhone uses 3rd?

Thank you

 

[jirkahtc]

Fault hw, microphone 1+2

 

[Reflej0]

I understand that the additional microphones are activated when making a video recording, as long as the Lumia Camera program (which is discontinued) is used.
To manage the microphones outside the video shoot, that is, in other areas I do not know if it is possible.