Archaeoacoustics falls within the field of archeology and studies the acoustics at archaeological sites across different cultures using an approach that combines physics, anthropology, and architecture.
This discipline began to emerge at the end of the 20th century thanks to field work that drew a connection between examples of prehistoric rock art and the acoustics in the locations where they were found (Dauvois (1988), and Waller (1993)). It was during this same era, when studies of lithophones at the Caves of Nerja contributed to this body of knowledge (Dams, 1984 and 1985). Decades later, the studies have become even more advanced. (Jiménez González, 2008; Díaz-Andreu, 2012-2014; and the Songs of the Caves project).
Archaeological acoustics introduced the idea of taking acoustical measurements that provide data about different human activities — social, political, religious, etc. — from various cultures in the past, and establishing connections with their present-day artifacts. It studies the acoustics of archaeological remnants in order to be able to reconstruct the audio-musical landscape of the past.
From a methodological standpoint, quantitative elements and factors (musical instruments, building materials, spacial measurements, and a consideration of the location features; in short, all of that which comprises the acoustic engineering) as well as conceptual tools need to be incorporated into the work. What this means is that in order to be able to propose and establish well-founded hypotheses and develop useful links between theory and practice, mathematical models are necessary, on both an abstract level as well as in their application at a numeric level.
Sound and auditory phenomena should be understood and examined on different planes, taking note of both these planes and their relationships. Such planes include aspects such as the strictly physical, the cognitive, the physiological, and the meaning — this latter can be a part of various cultural, artistic and social manifestations — although these are not the only aspects to be considered.
Sound as a Natural Phenomenon
A protocol for acoustic measurements needs to be established in order to be able to address sound as a natural phenomenon. It is also important to take into account the materials of the structures themselves, especially in the case of restored structures, because during restoration building materials may have been used that differ from the original ones, thus giving rise to acoustic alterations caused by variations in the structure itself, temperature, humidity, and other physical conditions. The mathematical models will be developed once this data is available. From the mathematical standpoint, this acoustical research will be based on the presentation and resolution of a specific equation: the wave equation. Solving the equation recreates the virtual conditions that are not possible to reproduce in the experimental environment; it also serves as a tool to predict and verify the hypothesis.
Physical and Cognitive Aspects
The auditory process needs a receiver and, therefore, also needs the sound signal to be processed and decoded. Thus, in order to define the acoustic identity of an archaeological site, the way humans perceive the acoustics must be take into account. To this end, it is important to address the psychoacoustic aspects, the psychological responses to the sounds. Qualities that are attributed to the sound, such as whether it is strong or weak, can be analyzed alongside a relative context.
The Meaning of Sounds
Sounds may be imbued with meanings that can vary depending on the specific cultural context. In ancient Greece, low sounds and bass notes were associated with heavier movements and objects, and sharper sounds with lighter movements and objects. It was later when the western musical notation system was created and established a correlation to pitch: high-sharp, low-flat.
The Case of the Maya
In different places, such as Chichén Itzá, “musical rocks” or “musical cones” have been discovered: a set of rocks that, if struck, make different tones. These phenomena are not limited to present day Mayan sites, but also appear in other Pre-Columbian settlements (Teotihuacán, Monte Albán, etc.). But it is in Tulum where a very interesting acoustic product has been studied. On the roof of one of the structures, there is a cylinder next to which lies a ring, both are of made of stone and both positioned at the same level. Local guides claim that when the wind is strong reaching storm-level velocity, as occurs when a hurricane approaches from the coast, the whistle produced by the ring can be heard from kilometers away. If this is the case, it could be presumed to be one of the first meteorological alarm instruments, given that, as a walled settlement, Tulum would have provided protection to its inhabitants.
The methodological elements previously mentioned are key to validating these theories. And our understanding, both mathematical and physical, must be founded on experimental tests and archaeological data.
The area of archaeoacoustics represents a wide field of study, in which there is still much to be researched. It is known that ancient civilizations indisputably gave significant importance to acoustics. But the research must be carried out from various perspectives, from both scientific and humanist angles. Analytical, mathematical, experimental, etc. approaches are necessary because each of those in isolation cannot provide an integral view of acoustic phenomena.
There are numerous questions that arise from discoveries and their ensuing archaeological analysis; the work on acoustic effects in archaeological sites has a long path ahead and should be considered an emerging, all-encompassing discipline.
Dra. Ana González Menéndez
-Burkholder J.P., Grout D.J., Palisca C.V. (2019, updated edition): Historia de la Música Occidental. Alianza editorial. Colección Alianza Música. Madrid.
-Cross, Ian, Aaron, Watson (2006): Archaeoacoustics. “Acoustics and the Human Experience of Socially-Organized Sound”. Chris Scarre and Graeme Lawson (eds.). Cambridge, RU (McDonald Institute Monographs).
-Declercq, Nico F., Joris, Degrieck, Rudy, Briers, Oswald, Leroy (2004): A Theoretical Study of Special Acoustic Effects Caused by the Staircase of the El Castillo Pyramid at the Maya Ruins of Chichen-Itza in Mexico. J. Acoust. Soc. Am., 116 (6), 3328-3335.
-Garza E., Fernando J. (1996): Turismo acústico en Chichén Itzá. Discussion presented at the 3rd Mexican Acoustics Congress.
-Kinsler, Lawrence E., Austin R., Frey (eds.) (1950): Fundamentals of Acoustics. New York: John Wiley and Sons.
-Lubman D. (2002): Acoustical Features of Two Mayan Monuments at Chichen Itza: Accident or Design. J. Acoust. Soc. Am., 112 (5), 2285.