My wife and I just moved into our house; the A/C works great and cools off the house but the air intake vent in the living room is really loud, so much so that it drowns out the TV with the volume way up. My guess is that a solution might be to lower the fan speed, but I'm not sure how to do that.

It is a DUCANE HVAC system, not sure the model number. Any help or other suggestions for quieting it down would be appreciated.