October 2023 Newsletter: Ancient Architectural Acoustics

The world of modern architectural acoustics is still relatively young, with calculations and standards being refined to this day. This reality makes the acoustical achievements of the ancient world all the more impressive. Read on to learn about a few different ancient structures that produce impressive acoustic phenomenon!

The Pyramid of Kukulkán
Located in the center of the Chichén Itzá archaeological site of Mexico, the Pyramid of Kukulkán was a temple used by the ancient Mayans to worship Kukulcán, a feathered serpent deity. When one claps their hands near the base of the pyramid, the echo that resounds bears a striking resemblance to the quetzal, a bird that was sacred to the ancient Mayans. A closer look at this phenomenon reveals that the pyramid steps act as an acoustic diffraction grating created by the distances, angles, and heights of the steps. Did the ancient Mayans get lucky? Or did they purposefully design the Pyramid of Kukulkán to mimic the sound of one of their most sacred birds?

The Amphitheater of Epidaurus
The ancient Greeks were a people of art, culture, and knowledge. It is no surprise that theater was a huge part of ancient Greek society. The amphitheater of Epidaurus is an acoustic marvel, with an ideal location and stage symmetry to perform plays that everyone could enjoy. What really sets the Epidaurus theater apart from other ancient theaters, however, may lie in the seating. According to a 2007 study that was presented in the Journal of the Acoustical Society of America, the limestone seating appears to have certain acoustic properties that help reflect the higher frequencies of speech, critical to good intelligibility, while simultaneously diffusing lower frequency sound. This “filtering” effect reduces background noise from crowd murmurs and projects voices from actors to audience areas. It’s no wonder that modern acoustical techniques are based the techniques of the ancient Greeks, using a combination of absorption, diffusion, and reflection to create similar effects to that of the Epidaurus theater.

The Lazarica Church
Whether a priest whose words need to be heard clearly throughout a room full of people, or a choir whose voices need to fill an entire space, the acoustics of churches are more nuanced than many other buildings. The Lazarica Church is an ancient structure in Serbia that sets a great example for room acoustics and speech intelligibility. In 2019, a model of the Lazarica Church was created in which its domed ceiling was replaced with a flat ceiling. While this change made no significant difference in the reverberation time, speech intelligibility was reduced when the ceiling was flattened. The Lazarica Church is one of many ancient churches with a domed ceiling, but one of the few examples to show some benefit from this type of ceiling.

All of these acoustical marvels show us that we can continue to learn from existing designs as we move forward in our industry. If you have any examples of ancient acoustic phenomena, we would love to hear about it!

2023 AIA Award Winners
SenSV hits the convention floor