A lot of builders of 3-piece bows put some sort of buffer between the limbs and the riser. Helps to deaden squeaks and that type of noise. Vibration is something else.
First, be sure your limb bolts are tight, but not too tight or they will crack the glass. A brace height that's too low will cause the limbs to vibrate excessively. A nock point that's very high also tends to pull the limbs out of balance/tiller when drawn and released, creating more than normal vibration. An arrow that's way too light will also do it. Stretchy strings, like dacron, contribute to vibration noise, but usually not in a big way. Check these things out, it's probably one or more of them. Good luck.