Moto X low microphone sound - almost silenced! topic

Hi guys!
Sorry if my english it's not very good, im from Argentina

I have a Moto X with retail brasi kit kat 4.4.4
I started noticing that the mic's volume is reeeeeeeeeally low..
With a needle i've tried to clean de hole on the bottom of the screen but it did not work

Does anyone have a solution that actualy works?
Is there a soft or hard issue?

Thanks a lot!