A sound attenuating covering for an architectural opening is provided. The covering may include a frame, a first shade, and a second shade. The frame may include opposing side members, each defining an opposing channel extending along at least a portion of the side member. The first shade may be positioned forward of the frame and may define a plurality of horizontally-extending, transversely-collapsible cells. The second shade may be positioned rearward of the first shade and may be slidably received within the channels of the side members. The first and second shades may be operably coupled to a roller and may move in conjunction with one another across the architectural opening.