I’m glad to talk about the science involved, but, first, given that this is a very long tread I would like to get some clarity on a few points.

1. Just a picky point. The structure continually referred to as the “Temple of Kukulkan” is called the “Castillo” by Mayanists and is not a temple to Kukulkan. If any structure at Chichen would qualify as a temple to Kukulkan, it would be the observatory (“el Caracol”) because round temples were associated with Quetzalcoatl in Central Mexico.

I don’t have your original papers, but I assume the 08 Paris paper you provided has the essentials.

Assuming for the purpose of this discussion that the recorded echo from El Castillo at Chichen Itza is identical to the chirp of the quetzal and that this chirp is unique.

You argue that the quetzal chirp is produced by a stair with 26.2 cm tread, 26.4 cm rise and 91 steps. Have you recorded the identical quetzal chirp from any other Mesoamerican pyramid (or structure)?

Are all handclaps at any distance equal imputs (other than diminished volume) for the purpose of producing the quetzal sound?

Do all stone staircases produce some kind of “chirp” with handclaps?

As an acoustical scientist, how would you go about designing a stone structure to produce a quetzal chirp from a handclap?

Since the Maya did not have oscilloscopes, fourier equations, calculus, etc., isn’t trial and error the only way for them to have designed this kind of pyramid?

With regard to the Ball Court at Chichen, you say that a flutter sound is produced: Is this “flutter” produced by a handclap, or only as you say “A flutter echo was heard each time a ball impacted a wall of the playing field or the hard surfaces of a ballplayers protective gear. The flutter frequency for wall impact, just over 4 Hz. The flutter frequency for impact on player’s regalia is twice that. Perceptually, 4 Hz is the frequency of maximum human sensitivity for the auditory percept called “fluctuation strength” often chosen for warning signals because of its alerting properties.”

Have you recorded this “flutter”? Have you recorded jaguar growls and/or rattlesnake rattles and shown that these sounds correspond to the flutter at Chichen Itza?

It seems incongruous that an identical “flutter” would be produced by a ball striking a stone wall and the leather protective paraphernalia of the ball players.

Also, to produce a realistic “flutter” you really need to test the sound using a solid rubber ball of the appropriate size, because that is what was used.

Just to clarify:

Wayne Van Kirk claims that the Temple of the Warriors also produces a quetzal chirp + a rattlesnake sound. Have you recorded these sounds also? If so, why would a completely different stair also produce a quetzal chirp and a rattlesnake sound without the ball court walls.

Do you also argue (not a scientific question) that the feathered serpent at Chichen and the sounds associated with it go all the way back to Classical Maya?

Once the exact extent of the claims made are clarified, we can discuss further
Bernard