My ipone 4s top speaker is not working?

The other day I fixed my iPhones cracked screan and ever since the top speak that you use to receive phone calls has not been working. Everything else seams fine but I was wondering if anyone knew why this would be happening and if they do, which component of the internal workings of the phone is not working, thank you!

Loose it! Get a new phone.

If you take off the screen with a rubber poper. You can pop if off and there will be a little microchip on the top or 2 of them.pop them off and re-push them in.