Samsung Ativ S: the microphone in a speaker mode not working

[Leonid Z]

Hello,
In my case, the microphone not works in a speaker mode. What a problem might be here?

 

[worldspy99]

Probably the microphone is bad. There are atleast 2 or 3 mics on modern smartphones. Does it work fine when it is not in speakerphone mode?

 

[Leonid Z]

Yes, in a "not-speaker-mode" it works fine. Indeed (thanks for your help ) there are two microphones in this phone. The "bad" one is an upper. Now my problem is to understand, what is wrong: the microphone or the amplifier? When I am talking closely to this microphone, I can here some light echo in my phone, not on the other side of the line.