Page 15 - January 2009

Fig. 10. The elliptical room. As with Heidelberg’s echo, Kircher studied the effect of the ceiling shape.
analysed in particular the floor of the room, presuming the material used could contribute to the special acoustic effect. At that time, pavement in the so-called “Venetian style” became fashionable and extensively used in many palaces. This type of pavement, which still exists in several ancient palaces, is a mixture of mortar and stones; besides giving a pleasant aesthetic effect, once trampled, produces a singular sonorous effect Kircher emphatically compared to a thunder- ing crowd rushing in threatening pursuit.
The elliptical room. Kircher demonstrated his knowledge that the geometric shape of rooms would influence acoustic behavior. One of his most interesting studies is regarding the capability of elliptically shaped ceilings to transmit and rein- force the voice better than any other shape. Kircher under- stood that the ellipse, which has two foci, could be used for the construction of a room. With an ellipsoidal vault it would be possible to use these two foci for two people to communicate easily with each other at a distance (Fig. 10). Kircher’s intuition and consequent observations were of
course correct. In the ellipse every
outgoing straight line from a focus
will be directed to the other focus.
Moreover, the more reflective the
surfaces, the more concentrated are
the sounds. In such a case the prop-
erty of restitution of the sound is
effective and surprising. In order to
strengthen his observation, Kircher
also suggested the surfaces of the
inner walls of the ellipsoidal vault
should be cleaned with a mixture of
water and Arabic rubber to optimise
the acoustic effect.
Villa Simonetta. The descrip- tion of the Villa Simonetta, “just outside the Door of the Gardeners” in Milan, was of particular interest. Ferdinando Gonzaga, the Governor of the city at that time, built the villa and, as Kircher relates, it became more famous for its echoes than for its extraordinary and admirable
architectural symmetry. On the first floor there is a window (Fig. 11) where every word that is uttered projects reinforced in intensity and echoed four-fold. Moreover, if the words are projected with a stentorian voice, they are multiplied so many times they can be heard almost infinitely. Kircher, having heard from many people about the singular acoustic phe- nomenon in the villa, decided to discover what caused it, and therefore satisfy his own curiosity. He declared that P. Matteo Storr, a faithful and erudite clergyman of the Company of Jesus, already observed and diligently annotated the dimen- sions of the building and its architectural details.
The Villa Simonetta complex consists of three parts around a great courtyard opening at the back towards a luxu- riant garden. The façade is comprised of two porticoes with ten columns on each floor. The building has two floors sepa- rated by an ambulatory. On the ground floor, paving stones comprise the zone indicated by the letter K in Fig. 11. Laterally and parallel to this are the other two blocks, labeled XMVN and GFHL respectively. After having accurately described the measurements (height, length and width) of the three zones divided into dwellings, Kircher then moved his attention to the window where the famous echo is produced.
Some witnesses reported to Kircher that at this location the voice was multiplied 24 to 30 times according to its pitch. Kircher identified the cause of this as the proportion- al distance between the two parallel areas of the building, and in their perfect equality and absence of surface rough- ness. Furthermore, he demonstrated this thesis with the aid of a drawing (Fig. 12). Let us consider the walls AC and BD, which correspond to the two parallel zones of the Villa Simonetta; they are placed at a distance where it is possible to perceive, by means of the echo, words with two-syllables.
With the treatment of echo in the Phonurgia nova, Kircher made a remarkable contribution to feeding the
Fig. 11. V illa Simonetta.
14 Acoustics Today, January 2009