It is known that a handclap in front of the stairs of the great pyramid of Chichen Itza produces a chirp echo which sounds more or less like the sound of a Quetzal bird. The present work describes precise diffraction simulations and attempts to answer the critical question what physical effects cause the formation of the chirp echo. Comparison is made with experimental results obtained from David Lubman. Numerical simulations show that the echo shows a strong dependence on the kind of incident sound. Simulations are performed for a (delta function like) pulse and also for a real handclap. The effect of reflections on the ground in front of the pyramid is also discussed. The present work also explains why an observer seated on the lowest step of the pyramid hears the sound of raindrops falling in a water filled bucket instead of footstep sounds when people, situated higher up the pyramid, climb the stairs.

1.
Wayne
Van Kirk
, “
The accidental (acoustical) tourist
,”
J. Acoust. Soc. Am.
112
(
5
),
2284
(
2002
).
2.
David
Lubman
, “
Acoustical features of two Mayan monuments at Chichen Itza: Accident or design
,”
J. Acoust. Soc. Am.
112
(
5
),
2285
(
2002
).
3.
David
Lubman
, “
Singing stairs
,”
Sci. News (Washington, D. C.)
155
,
44
(
1999
).
4.
David
Lubman
, “
Mayan acoustics: Of rainbows and resplendent quetzals
,”
J. Acoust. Soc. Am.
106
(
4
),
2228
(
1999
).
5.
David
Lubman
, “
Archaeological acoustic study of chirped echo from the Mayan pyramid at Chichén Itzá
,”
J. Acoust. Soc. Am.
104
(
3
),
1763
(
1998
).
6.
Bijal P. Trivedi, “Was Maya Pyramid Designed to Chirp Like a Bird?” National Geographic Today, Dec. 6, 2002.
7.
Fernando J.
Elizondo-Garza
, “
Quetzal or not Quetzal, that is the question… on the stairs of the Castillo monument in Chichen Itza
,”
J. Acoust. Soc. Am.
112
(
5
),
2285
(
2002
).
8.
Jorge
Carrera
and
Sergio
Beristain
, “
Theoretical interpretation of a case study: Acoustic resonance in an archeological site
,”
J. Acoust. Soc. Am.
112
(
5
),
2285
(
2002
).
9.
J.-M.
Claeys
and
O.
Leroy
, “
Diffraction of plane waves by periodic surfaces
,”
Rev. Cethedec
72
,
183
193
(
1982
).
10.
J. M.
Claeys
,
Oswald
Leroy
,
Alain
Jungman
, and
Laszlo
Adler
, “
Diffraction of ultrasonic waves from periodically rough liquid–solid surface
,”
J. Appl. Phys.
54
(
10
),
5657
5662
(
1983
).
11.
Nico F.
Declercq
,
Joris
Degrieck
,
Rudy
Briers
, and
Oswald
Leroy
, “
A theoretical elucidation for the experimentally observed backward displacement of waves reflected from an interface having superimposed periodicity
,”
J. Acoust. Soc. Am.
112
(
5
),
2414
(
2002
);
Nico F.
Declercq
,
Joris
Degrieck
,
Rudy
Briers
, and
Oswald
Leroy
, “
Theoretical verification of the backward displacement of waves reflected from an interface having superimposed periodicity
,”
Appl. Phys. Lett.
82
(
15
),
2533
2534
(
2003
);
Nico F.
Declercq
,
Joris
Degrieck
,
Rudy
Briers
, and
Oswald
Leroy
, “
Theory of the backward beam displacement on periodically corrugated surfaces and its relation to leaky Scholte-Stoneley waves,” in press with
J. Appl. Phys.
12.
Sergio
Beristain
,
Cecilia
Coss
,
Gabriela
Aquino
, and
Jose
Negrete
, “
Tonal response on the stairway of the main pyramid at La Ciudela, Teotihuacan archeological site
,”
J. Acoust. Soc. Am.
112
(
5
),
2285
(
2002
);
paper 3aAA4 in Proceedings of the first PanAmerican/Iberian meeting on acoustics, 2002.
13.
David Lubman: http://www.ocasa.org/MayanPyramid.htm (site visited on 12/13/2002).
14.
Jacques R.
Chamuel
and
Gary H.
Brooke
, “
Transient Scholte wave transmission along rough liquid–solid interfaces
,”
J. Acoust. Soc. Am.
83
(
4
),
1336
1344
(
1988
).
15.
Leon Cohen, Time-Frequency Analysis (Prentice-Hall, Englewood Cliffs, NJ, 1995).
This content is only available via PDF.
You do not currently have access to this content.