Loud sound comes in fine. As far as manual audio control you're fairly limited with the onboard microphone. You can pick between two levels of sound: Normal and low. You can pick between 2.1 or 5.1, and that's about it.
If you need more specialized control you can always get a small pre-amp and a microphone and run it to the line in on the camera. I've done this with several microphones and it's come out quite well.