Iphone 4s microphone not working
So, my iphone 4s microphone does not work. When i talk to people via phone, i have to use speaker phone. Also, voice memos does not pick up any registered noise. I can listen to music and watch youtube without headphones and the speaker works fine. I don't completely mind the whole speakerphone thing, but i would like to have some privacy if i'm in public. Also, not sure if phone has warranty but screen is slightly cracked in the top right corner so not completely sure if apple would still cover it. If anyone has any kind of ideas on how to repair this, it would be greatly appreciated. Thanks.
iPhone 4S, iOS 6.0.1