I’m in the process of clearing out some ‘draft’ posts I’ve had sitting around too long, so expect a few short posts about various stories or topics of interest.

In this case, a story from Collision Detection about Mayan acoustics.

Researchers have analyzed Mayan tombs and found that they were designed to produce incredibly weird sound effects. If you stand in front of the staircase of the El Castillo pyramid and clap your hands, you’ll hear an echo that sounds like the chirp of a bird. If you walk up the stone steps, it produces a flurry of echoes that sounds like rain falling into a bucket. Declercq’s team has shown that the height and spacing of the pyramid’s steps creates like an acoustic filter that emphasizes some sound frequencies while suppressing others. But more detailed calculations of the acoustics shows that the echo is also influenced by other, more complex factors, such as the mix of frequencies of the sound source.

Very cool indeed. One of course wonders if this is intentional in the design of these structures. It looks like the answer at this point is: maybe?

A visitor to Collision Detection with first-hand experience seems convinced:

I was just in Chichen Itza this past spring and heard the effect you describe. As for whether it was intentional or not, I’m pretty convinced it was. The entire site is filled with sonic/mathmatical/astrological wonders. In the ball court, if you stand on one side and clap, you’ll hear the echo seven times (seven was a magic number for the Mayans, and is seen throughout their architecture and sculpture). The viewing booths/stages at either end of this court, when they were in better condition, could amplify a speakers voice so that they could be hear clearly at the other end of the court. On and on…

The most amazing though is the Kukulkan’s Pyramid. During the spring and fall equinoxes, as the sun rises and sets, it creates the “image” of Kukulkan (Chichen Itza’s serpent God), along the edge of one of the staircases. The image is made up of seven triangles from the edges of the pyramid (seven again) and when the farmers saw the snake going “up” (leaving the ground) or “down” (into the ground), they knew when it was time to plant seeds or harvest the crops.

Sounds amazing. Literally. :)

Ah, the wonders of blogging. If I had posted about this story when I first read it, I would have missed this personal comment, which in my mind, added more credibility to story than the original article.

Original story was at nature.com (reg. req’d).