My primary mic seems to be broken. Google Now voice search records no audio and while in call the other side can not hear me talk. Booting to safe mode does not help either.
However when I switch to speakerphone, all is working well. As far as I've read the Nexus 5 uses another mic in speaker phone mode (noise cancellation).
Is it somehow possible to always use the speakerphone mic? Since it is the only one working for me.