Here are a few ways to troubleshoot issues that may arise with your microphones.
Around the Sound
Microphones, both those that come on board with the digital video camera and those that you attach, are important for getting complete audio to associate your video. Without quality microphones you are back to amateur footage, which is neither aesthetically minded or artistically motivated. When using these high end peripherals a number of things can happen to disturb their proper functioning, and here are a few tips for troubleshooting what could be wrong with them.
If you are using a lavaliere microphone, whether corded or wireless, you may notice that there is a static hum in the background. This can be a number of things, but if it is a wireless microphone then you should take a look to see if there is any type of interference going on. Turn all cell phones off, avoid any type of radio interference, and if there is a broadcast station nearby you are going to have problems. If this is not the problem you should check to see if all parts of the microphone are properly screwed in. This means that the top of the microphone is securely fastened to the base where the sensitive parts are. This comes off fairly often and is a common problem.
When using a large boom microphone you need to make sure that the wind sock on it is just the right density. If you are getting muffled audio then it may be to thick and large, but if you are getting to much environmental noise you may need a denser one. Try to never go without one unless you need to get very sensitive sound, but in this case you would likely not being using a boom shotgun microphone.
If you have a consumer camcorder you are going to encounter a number of things. These can be interferences like the sound of the tape rolling internally or the creaks of the plastic case. These are unavoidable, but if you where accurate noise canceling headphones then you will be able to hear and avoid this interference. Other than this the best choice is to use an outside microphone.
If you are positioning a microphone in a certain direction and not getting the results you want you may end up having a different type of microphone then you thought. For example, unidirectional microphones can only capture sound that is right in front of them. If this is the case you have to point the microphone directly at the central action to get what you want.
If there is even more mysterious interference that you cannot trace it may go back to the cords you are using. Try to use only single cords for each connection and try to buy new ones regularly.