Repetition Pitch glide from the step pyramid at Chichen Itza.
Standing at the foot of the Mayan step pyramid at Chichen Itza in Mexico, one can produce a pitchy "chirp" echo by handclapping. As exposed by Declercq et al. [J. Acoust. Soc. Am. 116, 3328-3335 (2004)], an acoustic model based on optical Bragg diffraction at a periodic structure cannot explain satisfactorily the chirp-echo sonogram. Alternatively, considering the echo as a sequence of reflections, and given the dimensions of the pyramid and source-receiver position, the chirp is predicted correctly as a Repetition Pitch glide of which the pitch height is continuously decreasing within 177 ms from 796 to 471 Hz-equivalent.
Bilsen
Frans A
FA
fabilsen@xs4all.nl
D000162:Acoustics; D005160:Facility Design and Construction; D005583:Fourier Analysis; D006801:Humans; D008954:Models, Biological; D016011:Normal Distribution; D010898:Pitch Perception / Q000502:physiology*; D013018:Sound Spectrography