Q: can't hear callers except using speaker

hi,

you need to push hard on where front camera area, you'll hear a click sound. that's all.

Dude, thank you so much! Pressing hard on around the front camera area worked for me. I kept seeing people recommending the insert/remove headphones trick, hard reset, restore, etc. It seemed weird to me that I could hear audio when playing music or ring tones, but during voice calls or playing voice mails, I could only hear audio with headphones plugged in. If you can adjust volume and the volume level dialog does not say "Headphones" (even though you don't have headphones plugged in), then possibly the solution mentioned here is for you. This had nothing to do with headphone jack nor was it a setting - pure hardware issue - loose connection or short somewhere. Maybe this will help someone else.

Thanks man, this what helped me as well.

I know this question has been answerd but I have had this problem with my iphone4 on and off for two years and I wanted to offer the solution to my problem.  I tried banging on the speaker and it didn't work. I have tried everything and found the solution when I had to reset the bluetook sync on my car's audio system. The problem was definately related to the bluetooth. I deleted the bluetooth connection from both the car and and the phone, resync-ed the bluetooth connection and the problem went away. Somehow, I think the misconnected bluetooth settings turn off the incoming volume in the phone. I have, I think, had the same problem when I did not properly turn on or off the bluetooth connection when linking other devices to my phone, like a bluetooth headset.

So before you give up, and you think you have used a bluetooth device with your phone, try deleting the bluetooth settings and resyncing them and that may restore your incoming volume.

This is I fixed my issue.

Go to voice memo application and record a voice memo.  While listening to the recorded voice memo increase the volume. 

try turning ur vibrate on and off

Beware!  DO NOT LISTEN TO STEVEDURKO's ADVICE. He is instructing you to break your screen.

Can a member of admin take this idiotic suggestion off this thread asap. His instructions caused me to break my screen. That click he refers to is the snapping of your screen. Avoid his advice everyone.

Yeah - that cracked my screen. Thanks dude.

Thanks so much..... I just pressed hard on the front camera and I could hear voice calls again.

This was the immediate cure to my mysterious speaker problem. thanks for the help

You are a life saver. Thanks so much and you just saved me time and money. I thought I was going to have to buy a new phone.

I didn't press until I heard a click, but pressed hard and mine works again too

I press, here the click, it worked for some time and then happens again. Send for repair. Now it is back to normal.