Chosen Solution

Like i said in the title, bottom microphone of my iphone 4s don’t work. The top one working perfectly. So i can use the iphone only on speaker or with hands free earphone. When i record something with voice memos, I can hear on recording very low volume radio frequency noise. When I try to talk with someone, they can’t hear me, only the same very low volume noise. I already changed the microphone and nothing happened. What can I do?

The bottom microphone is contained in the dock connector part. Replacing it should solve your problem. Here is a link to the replacement guide: iPhone 4S Dock Connector Replacement