A waveguide assembly for guiding sound includes a chassis that provides a cavity configured to receive sound propagating in a forwards direction along a primary axis of the waveguide assembly; a fixed waveguide that is fixed with respect to the chassis and positioned on the primary axis of the waveguide assembly, wherein the fixed waveguide is spaced apart from the chassis and is configured to guide sound received by the cavity through at least one opening formed between the fixed waveguide element and the chassis; a moveable waveguide that is moveable with respect to the chassis between: a standby position in which the moveable waveguide is configured to obstruct the at least one opening and form a forward-facing surface of the waveguide assembly; an operational position in which the moveable waveguide is configured to allow sound to exit the cavity through the at least one opening.