Outgoing Voice problem I have bought Micromax AI few days back. my voice to the caller is not heard. it happened initially and it was ok after I turned off the phone, now same problem has come up, I did all switch off change sim but of no help.
The usual list of suspect could be:


The microphone on your phone; 
Carrier signal quality and finally
The phone's software.


Hence first rule out the problem in that order and isolate the issue.  For ruling out the first microphone issue, you could try a hands free kit (either wired or a Bluetooth one). For the second, from a fixed position you can call and try with some other operator's SIM and try receiving a call and check and try the same from a different area. With these combinations, enable only 3G mode and try all these again.

It would be a very very rare phenomenon for a phone's software to be an issue. In that case you'd not be alone. If you are a person who can mend with patching software components of your phone you can search Internet for patching radio related files. Else, best option would be to either return it or visit the service centre.