A plenum assembly for carrying air in a supply system includes a duct including an opening formed with an inner surface through which air can flow; a door supported for movement between multiple positions which distributes air to the desired output path; and a seal secured to the door. In a vehicles HVAC system, numerous doors are utilized to provide comfort to the passengers based upon user input. The potential exists that some positions of the doors my lead to unwanted noise. A modification to the seal of the door with variable gap widths alleviates this issue and improves satisfaction.