A mounting assembly for attaching and supporting an audio/visual device. The mounting assembly includes a frame including at least one cross member, at least one side member, and a moving member; and a support assembly including a pair of spaced apart first members and a pair of spaced apart second members. Each second member is attachable to the audio/visual device. The first members are movably coupled to the at least one cross member and the second members are movably coupled to the first members. The moving member is configured to move relative to the cross and side members, such that the size of the frame is adjustable.