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Fig. 9. Service stairwell under
and ears. However, this works best when we observe ani-
mals like ourselves—daytime dwellers whose sounds we can
hear. But relying on these techniques causes problems when
the subject of study is more exotic. For example, it was
largely thought that big brown bats (Eptesicus fuscus) hunt-
ed insects at night in clearings; however, it was not until
studies were carried out using thermal vision cameras,
allowing real-time tracking of the animals’ movements in
total darkness at a distance outside of the lab, that these lim-
itations were found to be artifacts. Big brown bats in fact
carry out highly acrobatic maneuvers even in thick vegeta-
1
tion. In this paper, James Simmons pointed out that the
limitations of the usual methods of observation restricted how behavior was assessed. The “system proved superior for making observations of bat behavior at night because the bats are nearly always visible and can be followed for as long as they remain in line-of-sight out to 50-100 m or so.” 2 And, what he concluded is that new technology enables us to come to new understandings of the world around us. This is what we discovered with the new equipment used to record at the Eiffel Tower. We were able to understand it and see it in a new way, through her sounds.
Throughout history few scientists have studied sound in relationship to structures. Christiaan Huygens in 1692 was possibly the first to map the movement of sound in space based on reflections. His discovery, “l’Echo” later became known as a Repetition Pitch, was discovered when Huygens “noticed that the noisy sound from a fountain pro-
duced a certain pitch. He was able to determine the height
of this pitch by matching it with the pitch produced by a
‘closed organ pipe.’” This work was later confirmed by
Bilsen in 1993, with contemporary methods and equip-
2
ment. Similar architectural pitch shifting was discovered at
the Kukulkan pyramid at Chichen Itza, a Mayan ruin in
3,4
There he discovered that hand claps are heard as chirps as they reflect off of the pyramid stairs. Lubman determined that these were period- ic reflections off of the stair surfaces. In addition, Anish Kumar described the interesting musicality of the Vitthala
Mexico in 1998 by David Lubman.
neath the summit. Credit: France Languérand.
Temple in Hampi in South India. If you strike a column
with your finger it produces a sound, with the frequency
5
varying, depending on the column struck. The increasing
interest in this crossover between architecture and acoustics
has also led to a steady growth in both research and practi-
cal applications of architectural acoustics for design of
human spaces ranging from symphony halls to quiet work
6
and architecture is that they analyze the physical nature of sound movement in relationship to the surface of a struc- ture—rooms in the case of Salter, stairs in the case of Huygens and Lubman, and columns in the case of Kumar. The difference between these works and what we accom- plished was that we recorded the actual vibrations trans-
areas.
What is compelling about these viewpoints on sound
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Sounds of the Eiffel Tower 35