Call quality using Iphone 4 has decreased all of a sudden!

[cap2587]

I have an Iphone 4 on the straight talk network. I am experiencing some indifferent sound quality when making phone calls. The people I am speaking to are complaining about low volume, muffled sound and not understanding everything I am saying. It was not previously like this on the same Iphone, therefore unsure what could be causing this to happen. The Iphone is in excellent condition. I have tried to restore the Iphone, but that does not seem to have done any good. Any ideas to solve this problem would be appreciated. Thanks

[Cowboy]

New sim card.... Try a new sim card if that doesnt fix it then its hardware and you probably need a new dock flex

[cap2587]

I think it must be hardware. I switched Iphones with my wife and am having the same issues using her Iphone, but she isn't having any issues with her SIM and my Iphone. The Iphone where having problems with was using the Life Proof Case. It did get dropped in Eggnog about 2 months ago which does correspond to the problem starting. However, the life proof case pretty much covers every part of the Iphone. iPhone Cases and iPad Cases | LifeProof

Thanks for the response.

[iRevival]

If you're having the same issues on her iPhone with you sim card in it then it has to be the sim card.