A noise-reducing attachment apparatus for a heat exchanger door is provided for facilitating attenuation of noise emanating from an electronics rack. The apparatus includes a frame structure configured to coupled to the heat exchanger door. The door includes in air opening and air-to-liquid heat exchanger, and air passing through the air opening also passes across the heat exchanger. The air opening facilitates passage of external air through the electronics rack. The frame structure defines in part an airflow channel through the apparatus, wherein air passing through the air opening also passes through the airflow channel when the apparatus is operatively coupled to the door. An acoustically absorptive material, which is coupled to the frame structure and at least partially defines the airflow opening through the apparatus, is selected and positioned to attenuate noise emanating from the electronics rack when the apparatus is coupled to the heat exchanger door.