A mild controversy this time; but don’t worry, this is confined to the world of acoustic archaeology and won’t be inflicting itself on the front page of the Guardian any time soon.
Said controversy surrounds the step-pyramid at the Mayan site of Chichen Itza, known either as the Temple of Kukulkan or El Castillo. As its name suggests it is thought to be a temple to the Mayan deity Kukulkan, meaning ‘feathered serpent’ in Yucatec Maya, and thought to be analogous to Quetzalcoatl of the Aztec pantheon. It’s pretty impressive as structures go, measuring 30 meters in height with 364 steps (91 steps on each side) leading up to the temple of Kukulkan at the top. El Castillo is reckoned to have had wider cosmological significance to the Mayans, as the 365 steps (including the temple itself) correspond to the 365 days of the Mayan Haab calendar and for two weeks surrounding the spring and autumn equinoxes the rising sun casts a shadow on the sides of the pyramids that aligns with serpent head statues at the bottom of the pyramid.
The debate (or at least, the one of many that I’m choosing to focus on) surrounds the acoustic phenomena that have been reported, namely the fact that a hand clap at the base of the pyramid reflects back in such a way that it seems to mimic the song of the Resplendent Quetzal. The steps form an acoustic filter and cause the sound waves that make up the hand clap to interfere with each other and create a pitch glide effect. More of the sites at Chichen Itza, such as the Great Ball Court demonstrate similar acoustic phenomena and the ability of the Mayan builders to exploit the properties of their architecture for specific ends has been compared by some to the ancient Greek builders of the theatre of Epiduarus, and its ability to suppress low frequency echo and leave vocal frequencies undisturbed.
There are more than a few issues however. Much of the pyramid has been restored, crucially the two staircases where the echoes are the strongest. As well as this, further observation has revealed multiple different observable echo effects, observers sitting at the bottom of the staircases have heard the echoes of footsteps further up as falling rain. Crucially unlike Epiduarus, where the purpose of the building can be fairly easily determined, which sound(s) the temple was specifically designed to produce are less obvious. The highly unusual nature of the echoes means that the behaviour of drums or other instruments played at the bottom of the pyramid are hard to predict and, frankly, as likely to have been the focus of the design as hand claps.
Personally, I find it easy to believe that the temple of Kukulcan in Chichen Itza was deliberately designed to exploit the acoustic effects of the design. It seems odd to me that the theatre of Epiduarus can be so unambiguously declared to have been designed with a specific acoustic effect in mind, namely the filtering of low frequencies to maintain the clarity of human speech, in the 4th century BC and yet there is still doubt surrounding how deliberate the acoustic phenomena at Chichen Itza, built over 1000 years later, are. Of course, the challenge is that there are so many unknowns about Mayan cosmology and the role of music in their religious ceremonies that it may prove impossible to ever determine exactly what the intent behind Chichen Itza’s acoustic design is.
Not much of a controversy in the end, was it?