Tuesday, January 24, 2012

The sound of archaeology

At Mesoamerican archeological sites you’ll frequently see groups of people facing long stairways and clapping their hands, listening for an unusual echo. Although indeed a strange sound, I always refused to clap with my groups. It seemed hokey to me, certainly not something to be encouraged on a study trip.

Why would the echo at an archeological site be different from any other stairway’s echo? For me this changed at the 1999 Palenque Round Table – an event that annually draws four to five hundred people with an interest in Maya archeology. The Round Table lasts a week – Monday through Friday.

Speakers start at the top of the hour and present for forty minutes, followed by twenty minutes of questions and answers. In 1999, so many people requested time to speak that organizers set aside Thursday and Friday afternoon for fifteen-minute talks – followed by five minutes of questions and answers – squeezing three speakers into each hour. Few speakers respected the time frame.

The only way to stay on schedule was to cancel the Qs & As. Tuesday I was the first in line for lunch. After making my way through the buffet I set off toward the most distant corner of the huge dining room hoping to eat my lunch in peace and quiet and not talk with anyone. I glanced over my shoulder and saw a man following me with his tray.

Before sitting down at what I already thought of as ‘my’ table, he asked if I spoke English. Reluctantly, I acknowledged that I do. After introducing himself, David Lubman proceeded to tell me that he was the last speaker on Thursday. Immediately I knew his presentation was important enough to be scheduled but that he had a lousy time frame.

Who was going to stick around for the last fifteen-minute talk on Thursday? He went on to tell me he had never been to one of these meetings before. In fact, up until two years earlier he had never even visited a Maya archeological site. Would I be willing to let him read me his paper and tell him if I thought it would be interesting to participants in the Round Table? “It’ll only take fifteen minutes,” he said. I already knew that.

I agreed, and he proceeded to read. On a Caribbean cruise with a stop at Cozumel he’d signed up for an optional overnight Chichen Itza tour. As was to be expected, his tour guide clapped in front of the stairway of the Castillo pyramid. Lubman was more intrigued than most by the strange echo because he’s an acoustical engineer.

He realized he needed to make a recording of the sound but it had to be when it was quiet with no loud tour guides, no noisy busses with their engines and air-conditioners running. Back in his hotel room he packed a high-quality tape recorder with directional microphones in his daypack. Serendipitously, his tour package included the evening light and sound show in Chichen’s main plaza. Along with his group, he returned to the site after dinner, daypack on his back. After the show he hung back, hid, and waited till all the visitors and park staff left.

Then he set up his recorder and microphones and clapped his hands. Satisfied with the recording’s quality he surreptitiously left the site – it would be just as bad to be caught sneaking out, as sneaking in. The following morning Lubman returned to Cozumel and reboarded his ship back to the United States. Back home, he obtained a recording of songs and chirpings of unusual birds of Mesoamerica and made a computergenerated graph of each recording.

The graph of the chirping of the quetzal bird was virtually identical to that of the echo! This is particularly fascinating as the quetzal’s long tail feathers were the most prized for headdresses of Mesoamerica’s ruling class. In fact in Nahuatl, ‘quetzal’ is synonymous with ‘precious’. Indeed, it is the first half of the god Quetzalcoatl’s name. David Lubman asked if I thought his paper would be of interest to the group gathered for the Round Table. I told him, “They’ll be fascinated.”

Over lunch I had an uninterrupted opportunity to ask him all the questions I wanted. I learned that this type of echo only occurs on stairways in which the tread is shorter than the height of the risers. This combination gives the echo a ‘chir-roop’ sound which first ascends, then falls nearly an octave.

I attended Lubman’s talk on Thursday afternoon. It was just as he had read it to me at lunch on Tuesday. I stayed for some of the questions and answers and then went to dinner. An hour later I returned to the auditorium; Lubman was still answering questions about this whole new facet of archeology.

Who ever thought we’d be able to graph sounds? It turned out he had the best time frame of all. With no speaker scheduled after him he continued answering questions into the night. I now unabashedly clap at archeological sites and always look forward to hearing the now familiar chir-roop of the quetzal.


  1. So interesting! We're staying in Macario Gomez and several mornings I've heard this bird. I'm a sound mixer so I carry a small recorder with me to capture ambient sound when I travel. Thanks for the heads up about the steps.

  2. Okay, but how could an ancient civilization construct acoustical architecture? Where is the providence (earlier sites, acoustic study, other examples)? I love this story and have heard it recounted by guides at the site. But it seams almost impossible to accept as a scientifically-valid connection.