The Singing Pyramid?

February 8, 2005 4:00 AM

Mystery of 'chirping' pyramid decoded: "A theory that the ancient Mayans built their pyramids to act as giant resonators to produce strange and evocative echoes has been supported by a team of Belgian scientists." Others are not so sure... Coincidence, or engineering? Did the designers of El Castillo pyramid cannily build in a sound effect that mimics the warble of the sacred quetzal bird? Listen for yourself, with the .wav file (first set is the real bird, the second is the pyramid) featured in this Acoustical Society of America page. I prefer to think it's deliberate; after all, it's possible that early man was experimenting with cave acoustics to to create sound-enhanced rock art (there are sound samples for this included here - unfortunately a Geocities site). Also of interest, the BBC programme "Acoustic Shadows" (requires RealPlayer - *heavy sigh*).
posted by taz (24 comments total)

I think that's officially in the "neato" pile.
Good post, taz.
posted by NinjaPirate at 4:26 AM on February 8, 2005

I was at Chichen Itza last week and our hired guide took great joy in showing off this trick, as well as the acoustic properties of the ball court. Very neat stuff.
posted by daveleck at 4:40 AM on February 8, 2005

The difficulty is, this ringing effect - an 'echelon echo' - is produced by all regular stone/concrete steps (it becomes a 'chirp' if the flight is high enough that the distance between successive wavefronts goes signficantly non-linear). You build a big structure and want a way for people to walk up to the top: you have steps. So how can anyone be sure the acoustics were intentional?
posted by raygirvan at 5:09 AM on February 8, 2005

I presume that this isn't what Radiohead were trying to achieve when they came up with the "Pyramid Song... ;-)

Interesting post, taz - but although it's been pointed out that different effects are achieved by different "source" sounds, I'm dubious as to whether the position of the observer has any impact upon what they hear... the priests at the top of the pyramid may have heard one thing, the commoners at the bottom, another.
posted by Chunder at 5:16 AM on February 8, 2005

I wonder. I remember finding out that Egyptians really didn't know about Pi; but if you look at the work they did it would be impossible to believe they didn't know Pi to some level far beyond the known knowledge of the time.
The bubble burst when someone figured out that if you use a cylindar to measure distance (i.e. roll a barrel and each turn of the barrel is a measurement.) Pi is built into this method.

Wow. Is it possible this is the same thing or were they just wacky genious?

Please note the Egyptians were still pretty advanced, just not math phenomes.
posted by fluffycreature at 5:22 AM on February 8, 2005

Chunder - our guide was very deliberate in having us stand in about 100 feet from the base of the pyramid, directly in front of the steps. Also, he mentioned that you cannot hear the sound at all if you are on top (we did not hear/notice anyone trying to elicit the sound while we were standing at the top).
posted by daveleck at 5:32 AM on February 8, 2005

"Echelon echo" is proving difficult to find on the Web (crappy search engine traps contain the phrase).

What's going on is that the clap makes a sharp sound pulse. The wavefront goes away from you, reflects from the vertical of the first step, then a bit later from the step above, and so on. So you're hearing successive sharp echoes coming back "clapclapclapclap" a few miliseconds apart ... ie audio frequency.

As the wavefront goes higher and higher up the steps, the angle makes the distance between successive reflections increase, so the pitch drops, and you get a "cheeeuuu" sound.
posted by raygirvan at 5:51 AM on February 8, 2005

if real audio has you down taz, why not try real alternative?
posted by xmattxfx at 6:09 AM on February 8, 2005

Cool stuff. I'm also dubious, but then again, these are the same steps that manage to form the snake-body of Quetzalcoatl at the equinox (also Real, Spanish).
posted by steef at 6:22 AM on February 8, 2005

Another Chichen Itza vet here ... Just as daveleck says, you do have to stand in a specific place to get the full acoustic effect of the phenomenon. It was pretty neat! Nice links, taz!
posted by carter at 6:26 AM on February 8, 2005

Yep, I was there three weeks ago too, and it worked as daveleck says. The whole place is well set up for acoustics, actually, and it was incredibly cool.

Great post, I'm looking forward to going through all the links in detail when I'm somewhere that I can listen to audio. :)
posted by livii at 6:48 AM on February 8, 2005

Very cool. I know a lot of Indian Moghul palaces were built to have spots where the guards could clap or holler to alert the others of invaders via echoes.
posted by riffola at 7:06 AM on February 8, 2005

Neat stuff. Thanks Taz.
posted by dazed_one at 7:31 AM on February 8, 2005

Fascinating! Thanks for the goods!
posted by mrs.pants at 7:53 AM on February 8, 2005

I know a lot of Indian Moghul palaces were built to have spots where the guards could clap or holler to alert the others of invaders via echoes.

That's interesting - do you have any links for that, riffola?
posted by carter at 8:16 AM on February 8, 2005

a link to what raygirvan was talking about
with additional echo goodness inside too
posted by forforf at 8:18 AM on February 8, 2005

I also visited Chichen Itza last week and I was most enthralled by the acoustic effects.

Raygirvan, apparently the steps at Kukulkan are not uniform from bottom to top. They have a high rise to run ratio at the bottom that decreases toward the top. The effect modulates the tone and pitch of the echo to make it sound more "chirp" like. (Man, those steps are a bitch to climb and they are even more treacherous on the way down!)

Bruce Sterling's Dead Media Project researchers consider that the chirping echo may be "the world's oldest known sound recording."

The acoustics of the ball court at Chichen Itza are equally impressive. A sound produced within the court generates at least nine discernible echoes.

Chi cheen Itsa’s famous “Ball-court” or Temple of the Maize cult offers the visitor besides its mystery and impressive architecture, its marvellous acoustics. If a person standing under either ring claps his hands or yells, the sound produced will be repeated several times gradually losing its volume, A single revolver shot seems machine-gun fire. The sound waves travel with equal force to East or West, day or night. disregarding the wind’s direction. Anyone speaking in a normal voice from the “Forum” can be clearly heard in the “Sacred Tribune” five hundred feet away or vice-versa. If a short sentence, for example, “Do you hear me?” is pronounced it will be repeated word by word... Parties from one extreme to the other can hold a conversation without raising their voices.

This transmission of sound, as yet unexplained, has been discussed by architects and archaeologists ... Most of them used to consider it as fanciful due to the ruined conditions of the structure but, on the contrary, we who have engaged in its reconstruction know well that the sound volume, instead of disappearing, has become stronger and clearer... Undoubtedly we must consider this feat of acoustics as another noteworthy achievement of engineering realized millenniums ago by the Maya technicians.

—Chi Cheen Itza by Manuel Cirerol Sansores, 1947 [via Chris Bracken's Chichen Itza travelogue].

posted by wrongbutton at 8:32 AM on February 8, 2005

Seems they call echelon echo a "picket fence echo" these days. This page has a nice animation showing how it works.
posted by raygirvan at 8:59 AM on February 8, 2005

Wow, this is rich. Thanks taz and all.
posted by semmi at 9:07 AM on February 8, 2005

Wow, thanks guys!! Cool stuff.

But I still blame Bush.
posted by Balisong at 9:54 AM on February 8, 2005

Hmmm. All I'll say is, look at modern structures that have interesting acoustical effects. Check out the Whispering Gallery in St Paul's Cathedral. Did Sir Christopher Wren plan that, or is it a side-effect of the necessary circular construcion of the dome? I think this Chicken Itza stuff is absolute shite: wishful interpretation of similarly unplanned acoustic effects.
posted by raygirvan at 6:10 PM on February 8, 2005

This also reminds me of the phenomenon described as having been observed in one of the "Colossi of Memnon" in Luxor.

Theories are that the sun heated up air, or possibly condensation which had collected in the cracks of the statue overnight, the escaping air/vapor caused vibration which resulted in the singing sound.

Repairs to the statue undertaken in the 2nd Century seem to have caused the phenomenon to cease.
posted by darkstar at 7:00 PM on February 8, 2005

Great story, darkster!

What's interesting about the chirping is that if the Mayans did it on purpose, it's amazing, but if they didn't, it's almost more amazing, given the importance of the quetzal in their religion.

Either way, the details that they did build into the pyramid are impressive enough. From the El Castillo link in the post:

There are many numerical details regarding the location of this structure that could not have all occurred by accident. Each side of the pyramid is made up of nine larger tiers or layers with a staircase in the center of each side leading to the temple at the top. Each stairway consists of ninety one steps, with one step at the top common to all four sides, for a total of three hundred and sixty five steps, the exact number of days in a solar year. Each side of the pyramid has fifty two rectangular panels, equal to the number of years in the Mayan cycle (at the conclusion of which they typically constructed a newer structure over an older one). The stairways divide the tiers on any given side into two sets of nine for a total of 18 tiers which corresponds to the 18 months in the Mayan calendar. The "square" that makes up the overall base of the structure is exactly 18 degrees from the vertical. Every aspect of the structure relates in some way to the Maya and their culture. The very physical presence of this structure and the shadows it casts, are also significant within the Mayan culture and are more fully explained in here the section detailing the Shadow Of The Equinox. The Maya universe was comprised of 13 "compartments" in 7 levels with each compartment being ruled over by a different god. El Castillo reflects these beliefs as seen in the shadows it casts. 7 levels are shown in the 7 light triangles. 7 Triangles of light and 6 darker triangles give 13 triangles in all corresponding to the 13 overall levels of the underworld.

(ps to xmattxfx : thanks for the Real Alternative link!)
posted by taz at 12:38 AM on February 9, 2005

Awesome post, I'm so glad I got to hear that sound.. This will have to do until I get there in real life, which will be soon I hope. :)
posted by dabitch at 9:07 AM on February 14, 2005