Mystery of the Chirping Pyramid Solved

Ant writes "Nature says the mystery of the 'chirping' pyramid has been decoded. Acoustic analysis shows how the temple transforms echoes into sounds of nature. El Castillo's strange echoes have fascinated visitors for generations. 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."

Re:For how long?

[WaterBreath]

Insightful??? Read-the-freaking-article before you make wise-crack comments, and especially before you mod them up. It was specifically the chirping effect of clapping sounds that was recognized in 1998. The "surprising sounds" in general have been known for a long time.

Re:For how long?

[SloWave]

I know that long before 1998 tour guides at Chitzen Itza would clap their hands in front of El Castillo and point out how the echo sounded like an eagle. They also would mention that the effect was intentional. I can't really believe that someone would pass this off as a new discovery. My guess is the article got it wrong and the researchers are presenting an analysis of the effect and some new evidence.

You can hear this at Fireworks shows

[wowbagger]

If you go to a fireworks show where there are bleachers nearby, you can hear the same effect - as each retort goes off, you will hear a "fhweeep!" as the impulse from the report crosses the bleachers.

In effect, you are convolving an impulse (the report or hand-clap) with a series of impulses (the steps) to yield a series of impulses.

(and for other signal processing/math pedants out there - yes, a handclap only approximates an impulse, as do the stairs.)

Re:You can hear this at Fireworks shows

[John Hasler]

A corrugated-steel wall produces this effect quite distinctly.

Bird calls designed to resemble Mayan echos

[goombah99]

Perhaps they have it all backwards. Bird calls are picked by birds on the basis of many factors. Beyong the obvious need to differentiate for sexual selection and niche indentity there are practical consideration on how they differentiate.

For example, do you want to optimize your call so that it travels well over water, through bushes, in heavy winds, tree-tops, urban landscapes? Maybe you want it not to travel far or make it hard to echo-locate for predator avoidance? Finally there is the problem o

Re:You can hear this at Fireworks shows

[D0 J00 W4n7 K4r473]

You mean it's not the aliens? *takes off tinfoil hat*

Re:You can hear this at Fireworks shows

[bar-agent]

You mean it's not the aliens? *takes off tinfoil hat*

NO! Don't take off the--too late.

You know, the mind control satellites are still up there. But now, of course, since you took off the hat, you don't believe me.

Re:You can hear this at Fireworks shows

[gardyloo]

Hm. Presumably, then, by measuring the spacing between the steps and the fundamental frequency of the sound (maybe with a pitch pipe -- one of the electronic ones for tuning would be even easier), you could measure the speed of sound in air for that day.

God, I'm geeky.

Plural

[erykjj]

The plural of "Maya" is "Maya" or Mayas"

Re:Plural

[jpsst34]

Yeah. That's great. But a Maya Person is a Mayan [reference.com]. I'm not a Pennsylvania.

Re:Plural

[erykjj]

Not to nitpick, but that same reference does not use the word "Mayans" in the plural. Instead, it says "n. A Maya; adj. Of or relating to the Mayas, their culture, or the Mayan linguistic stock". Saying "ancient Mayans" is not correct when you're speaking of the culture/group of people. If you're talking about the individuals, you could get away with it, but then the individuals would not be "ancient".

And picket fences, too

[G4from128k]

Walking on gravel next to a picket fence produces similar strange echoes. The fence acts as a grating and the relative angle of the percussive sound waves against the regularly-spaced pickets mean that different frequencies echo from different parts of the fence. The result is a chirping echo that sounds like it is from a moving source.

Weird Echo?

[yabbo]

I use that old "echo excuse" whenever I pass gas. I guess the Maya were way ahead of me...

the REASON?

[mehu]

Ancient Mayan 1: Gee, I really wish I could make some strange and evocative echoes...
Ancient Mayan 2: Hey, I know! Let's build a pyramid! It'll act as a giant resonator!

Yeah, I'm sure that's how it went...

First hand

[Thyamine]

My wife and I were able to experience this first hand. It's quite amazing to stand in the courtyard in front of the pyramid and do it yourself, although it's more interesting if you believe they did it on purpose. =)

Our tour guide pointed out another similar effect involving The Temple of the Warriors (I believe that was the one) while standing in the same spot. When facing it you can generate the sound of a rattlesnake (open to interpretation of course) which is to praise their sepent god.

The guide also said that priests standing in the temple atop the pyramid would only be able to be heard by someone standing in the correct spot in the courtyard. We didn't get to test that ourselves, but is something I had wanted to find out more about.

Re:First hand

[Guignol]

That last part is the most likely to be true as in "intended"
It's an 'elliptic' effect:
You put yourself in one focal point and say something
The sound waves will leave you circularly enough that they will reform in a good percentage of the original output at the other focal point, which is the spot you mention

There is a temple in Japan...

[alan_dershowitz]

I visited a Buddhist temple in Japan in 1993 that had a similar effect if you stood in one place and clapped. I don't think it was intentional. It was obvious people had been doing it for years though, because the varnish was worn off the floor in that area, and the wood was ground into a smooth indentation from all the people standing there trying it.