The tympanum, the triangular area within the pediment, is often decorated with relief sculpture. Above the tympanum is a prominent cornice with balustraded parapet. A carved tympanum generally constitutes the major sculptural work of a Romanesque church. Makaras are usually part of the decorative carving on a lintel, tympanum, or wall. One glazed roundel is at the middle of each tympanum. Carvings above the tympanum of 24 Patriarchs and Prophets were completely removed. The ability of the tympanum and stapes to effectively transmit vibrations is called impedance matching. The tympanum of the arch contains an empty niche. Males also have internal vocal sacs located between the tympanum and the foreleg. The northern tympanum mosaics feature various saints. A lateral fold extends from the eye to the posterior portion of the tympanum. In the center of the tympanum is the Archangel Michael. They left an inscription in Serbian lettering on the tympanum of the west portal. The allegorical sculpture group of the tympanum was destroyed. The base of the bimah repeats the twelve vine motif found on the tympanum.