bluetooth car radio call problem

Dec 29, 2014
I have redmi 1s, with last miui v5 stable rom 45.
I connect the redmi1s on car radio sony using blutooth, connection is ok, music play well in the car.
When I receive or make a call the sound is very bad, imposible to understand caller and caller undestand me.
Before it was all good with my galaxyS1.
That's very unpleasant, I like this phone but I need use it in my car.
Do you know an issue ?