sound quality calls.....

Jan 6, 2013
Hi people!
I have my new Xiaomi MI2. The phone is really great, and works so far stable.

What I have figured out, that the sound quality in the GSM calls is really weak. Has it got something todo with the android version, or is it the phone itself?!

Compared to the Xperia S I had before, the conversations were really loud and clear.....

My MIUI Rom is: JLB7.0 (Stable Build)

And ideas?!