A test apparatus for binaurally-coupled acoustic devices is disclosed. The apparatus includes a base, a lid, a primary speaker, and a binaural test fixture. The lid is coupled to the base and movable between a closed position in which the lid and base cooperate to form a closed sound chamber that is symmetric about a vertical mirror plane, and an open position. The primary speaker is coupled to one of the base and the lid, and faces a direction that lies on the mirror plane. The binaural test fixture is positioned inside the sound chamber, and includes first and second acoustic coupler mounts. The vertical mirror plane extends symmetrically between the first and second acoustic coupler mounts. A binaural test fixture, an acoustic coupler assembly, and a method of testing binaurally-coupled acoustic devices are also disclosed.