Whispering gallery at Chichen Itza's Great Ballcourt: Modern anomaly or original feature?

A "whispering gallery" (WG) at the Great Ballcourt (GBC) was first reported during its excavation in the 1920s by the storied American archaeologist Silvanus Morley (1883-1948), Director of Carnegie Institution's Chichen Itza project. In a 1925 National Geographic's article he wrote: "Standing in this temple one can speak in a low voice & be heard distinctly at the other end of the court, 500 feet away." About 75 years later (2001), Mesoamerican archaeologists posting on a discussion group stiffened at the suggestion that the ancient Maya possessed the requisite knowledge for intentional acoustic design. An original WG, if any, was surely a design accident. Morley's WG was dismissed as a meaningless artifact of reconstruction or ageing. Contemporary reports of WGs and other sonic effects were also dismissed. Some disbelieved that WGs exists today! At a tour of Chichen Itza following the fall 2002 joint acoustical meeting in Cancun, Mexico, the author and his colleagues convincingly demonstrated the WG to about 100 acousticians and their companions. This paper describes WGs and other remarkable acoustic phenomena at the GBC. Its acoustical reading of GBC architecture suggests the WG was present originally. Cultural motivations and opportunities for intentional design are discussed.