Good advice both about the pulley size and the blade. You remember some of the older blades that could really sing too? Piercing!The different pulley sizes change the RPM from the motor to the arbor. Motor at 3450, arbor at 5000 RPM for example.
Remove the blade and try it without.. I'm betting it's fine. Try a different blade then it will be fine. Some blades "sing" and other don't. :no: