Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
iPad Mini Suffers Microphone Issues
Just two months after receiving the iPad mini today I bumped in to a small problem when I tried to FaceTime a friend and realised that my microphone was not working. My friend could hear me tapping me on the iPad Mini’s screen and clicking the home button but could not hear me speaking. We thought that this may have just been an issue with FaceTime so we tried Skype , Siri and tried recording a video but we had no luck.
After some research I found that I was not the only one and found multiple reports of the same problem in many forums on the internet. With the great customer service Apple have we are pretty certain that Apple would replace your device straight away if you want back in to an Apple store and I will be heading there soon.
Update (Saturday 30th March 2013): Every since we published this article back at the beginning of 2013 Apple had seemed to fix the problem with the microphones on iPad Mini’s but over the last week we have had multiple reports of people purchasing iPad Mini’s specifically 16GB WiFi only models in which their iPad Mini microphones have not been working straight out of the box.
@macreviews just wanted to let you know after having my ipad mini 3 days, The m?c not work. Should I return to shop or take to apple?
— rebecca hughes (@Becky_Hughes82) March 30, 2013
Do not worry if this does happen to you the majority of people who have found the problem have got a replacement no questions asked and that is the Apple customer care you pay the premium on your devices for.