Original post by: Ben ,
Where is this noise coming from? This sounds like it's coming from the microphone. Try playing some music and see if you're hearing that noise. If not then try hearing it from recorded audio from the Voice Record app. If you hear it through voice record app. Then your bottom microphone is most likely at fault. If you can hear it while playing music then the loudspeaker is at fault. iPhone 4 Dock connector part: [product|IF182-009] How to replace Dock Connector (Charger port assembly)" [guide|3147] Here is the part for the loudspeaker: [product|IF182-013] Guide on how to replace loudspeaker: [guide|4360] I couldn't find any parts on iFixit where they have the iPhone 4 charging port flex cable assembly which comes together with the bottom microphone built in.