Very low incoming call volume on iPhone 4S

I recently noticed that the call volume is super low all of a sudden on my 4S, no matter how high I increase the volume. The speaker phone sounds normal and also music, but can't here callers speak very clearly when phone to ear. I have turned the phone off and then back on, problem still persist.


Is anyone else having this issue ? What wrong here ?

 

Thanks Mrbobb, I actual used a small alcohol pad along with a combination of sucking air out of the earpiece on iPhone and now sound is back to 100%. Make sure not to get excess liquid in the earpiece or you will have other problems. I guess it was a build up of a combination of pocket lint, dust and earwax.

Good to know that my iPhone was not damaged.

Hopefully someone else with this issue, sees this post and it helps.