crazykirbydude
Yes, bad bearings, dried oil, broken or loose fan, can all contribute to excessive noise and vibration. When it happens to a vacuum you know and use every day, it's how you can tell something is not OK with the motor, as it sounds different than normal (i.e. louder).
Now sometimes, yes, mostly with compact vacuums with tiny motors or high power vacuums with high RPM motors they can be loud just to be loud by design on purpose.