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"Faster: The Acceleration of Just About Everything"
The more efficient we get the less efficient we feel, and other paradoxes of the sped-up world.
By Edward Neuert
[09/15/99]

Jelly maker
Despite what liberal critics say, Michael Jordan is the true heir to the radical legacy of Muhammad Ali.
By Larry S. Platt
[09/14/99]

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The "Blood in the Sun" trilogy
In a wild, exuberant trilogy, Africa's greatest novelist sets out on a warping exploration of Somalian life and consciousness.
By Anderson Tepper
[09/14/99]

Dear Mr. Blue
When I'm 63
I love sex and I love men, but the only ones who ever ask me out are married. Where can I go to meet interesting, sexy men?
By Garrison Keillor
[09/14/99]

Book Bag
Guided tours of dystopia
The author of "Birds of America" selects five favorite novels about the future.
By Lorrie Moore
[09/13/99]

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Until recently, this question seemed unanswerable. How, after all, does one prove intent when the architects of a building have been dead for a millennium? But thanks to an emerging new field -- acoustical archaeology -- it may now be possible to shed new light on this and other enduring mysteries once thought to be irretrievably locked in the past. Taking a literal riff on the German poet Goethe's reference to architecture as "frozen music," acoustical archaeologists believe important information about the past can be gleaned from the acoustics of ancient structures.

The unusually sophisticated acoustics of Mayan temples have puzzled visitors for years. And understandably so: In the Great Ball Court at Chichen Itza -- 545 feet long and 225 feet wide -- a whisper at one end can be heard clearly at the other. But sound is an aspect that, until now, has largely been ignored by archaeologists. Nor have acousticians taken much interest in work usually done by archaeologists. But the traditional boundaries that have kept the two fields apart are beginning to blur as a handful of respected acousticians apply their expertise to such acoustical phenomena.

Among them is David Lubman, an acoustical consultant in Westminster, Calif., who frequently serves as an expert witness in civil and criminal trials. That's his bread and butter. His passion is studying the strange acoustical effects of ancient Mayan architecture, particularly at Chichen Itza, a former Maya-Toltec city in the northern Yucatan region of Mexico. Intrigued by the debate surrounding the mysterious chirped echo, he is the first to make scientific measurements of the echo and provide a scientifically credible explanation of its cause.

The science behind the sound turns out to be quite simple. Staircases are periodic elements -- that is, they are repeated at regular intervals in a region of space. The gaps in the step faces constitute a diffraction grating, causing a series of periodic sound-wave reflections, or tonal echoes -- a phenomenon commonly known as a "picket fence effect." Lubman likens the effect to a rainbow. "An optical diffraction grating transforms white light, spreading its frequencies over space," he explains. "An acoustical diffraction grating transforms white noise by spreading its frequencies over time." The chirped echo, in other words, is a rainbow of sound.

Lubman compared sound recordings of a quetzal chirping in its natural rain-forest habitat and the echo. They weren't identical, but he found striking similarities in sound quality, frequency, length and harmonic structure -- striking enough to convince him that the echo was intentionally designed to mimic the quetzal's call.

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