try tighting everything first and if you still have a noise try limbsaver products they really do work.I'm not sponsered by them but use them on everything!
As what was stated earlier...Take it too a bow shop and have them look it over...Has it always been that loud or making that noise?...Could possibly be a cracked limb. Have the shop double check it before it even gets fired again. If the limbs are fine,then maybe you just need some silencers or limb savers. How old is the bow?
The first thing I'd do is take it to a pro shop and see that it is all in tune. After that I'd put some type of vibration control product on the limbs. Limbsaver work pretty good, and they're not that expensive. If you use a fall away rest, sometimes those need tuned up as well. My bow used to make a noise after every shot, and it ended up being my fall away rest snapping back into place.