Deep beneath the rugged landscapes of modern-day Turkey lies one of the most remarkable archaeological marvels of human history: the underground city of Derinkuyu. This subterranean labyrinth stretches across seven levels below the earth's surface, once sheltering as many as 20,000 inhabitants from external threats such as invading forces and severe weather conditions. Yet, beyond its architectural and historical significance, Derinkuyu harbors a hidden dimension that has intrigued researchers for decades -- its unique acoustic environment. Recently, Sezin Nas, a leading researcher in interior architecture and acoustics at Istanbul Galata University, has ventured into uncharted territory by reconstructing the ancient soundscape of Derinkuyu to unravel how sound shaped the lived experience inside this extraordinary underground metropolis.
Derinkuyu's intricate network of tunnels, chambers, and ventilation shafts challenges conventional ideas about urban spaces. While most historical urban settlements are studied through their visible ruins, Derinkuyu presents an interior environment on an unprecedented urban scale, where architecture and acoustics intermingle in complex ways. At its core, Derinkuyu functioned not only as a refuge but also as a living, breathing city with multifaceted needs, including communication, ventilation, and social interaction. Nas argues that the auditory qualities of this underground city have been largely overlooked by scholars, and that understanding its soundscape is essential to appreciating how inhabitants experienced spatiality and social organization underground.
Central to Derinkuyu's extraordinary design is its multifunctional ventilation system. The city is equipped with four main ventilation shafts, supplemented by more than 50,000 smaller air passages that served multiple purposes simultaneously. These shafts did not merely provide fresh air; they were ingeniously integrated to facilitate communication and acoustic transmission across disparate parts of the city. Nas's research reveals how these architectural elements played a pivotal role in shaping the complex acoustic ecology that characterized Derinkuyu's interior spaces, influencing how sound traveled and was perceived in the labyrinth below.
To reconstruct the lost soundscape, Nas undertook a comprehensive and interdisciplinary study merging archaeology, architectural history, and acoustical science. She focused on three primary types of spaces within Derinkuyu: a church, a living area, and a kitchen, each with distinct functional characteristics and sonic signatures. By examining their geometric configurations, surface materials, and intended uses, Nas was able to model how sound behaved within these chambers. This included measuring reverberation times, reflection patterns, and the interaction between human-generated noises and architectural features, all critical for developing an authentic aural model of the ancient city's soundscape.
Employing advanced 3D virtual soundscape technologies, Nas created immersive auditory simulations that enable listeners to step into the echoes of the past. This digital reconstruction offers a rare opportunity to experience not just the visual ruins of Derinkuyu, but its acoustic environment as well. By layering historical knowledge with precise acoustic measurements, these simulations convey how sound influenced everyday life -- from communal gatherings and religious rituals to daily communication and even the subtle ambiance that permeated the underground city's corridors.
Nas presented her pioneering work at the 188th Meeting of the Acoustical Society of America, convening alongside the 25th International Congress on Acoustics. Her findings highlight fundamental contrasts between underground urban acoustic environments and the more commonly studied open-air urban soundscapes. Unlike cities that are defined by their skyward openness and diffusive spaces, underground cities like Derinkuyu create enclosed, highly reflective acoustic habitats where sound behaves distinctly, influencing social interaction in unexpected ways.
Perhaps one of the most intriguing revelations from Nas's research is the role that sound played in social organization within Derinkuyu. The city's unique acoustic properties potentially affected social hierarchies, communication protocols, and the spatial use of interiors. Sound was more than background noise; it was embedded into the architecture and daily life, facilitating interaction across spatial divides within the complex subterranean environment. This acknowledgment repositions acoustic design as a key cultural and functional dimension of ancient urban planning.
Nas's research also carries significant implications for modern urban design, particularly in the growing field of underground construction. As contemporary cities face increasing pressures on surface space, architects and planners are turning toward subterranean solutions for housing, transportation, and commerce. The acoustic insights gained from Derinkuyu's ventilation systems and soundscape could inform the development of future underground urban areas, ensuring that sound environments support wellbeing, communication, and social cohesion beneath the surface.
Moreover, the study of historical soundscapes, as emphasized by Nas, should become a systematic tool in cultural heritage preservation. In many cases, acoustic heritage is overlooked, despite its profound impact on the sensory experience of past societies. By reviving the auditory past, researchers can gain a richer, multi-dimensional understanding of historic spaces, challenging the primacy of visual-centric archaeological narratives. Derinkuyu stands as a testament to how sound is as integral to urban identity and cultural continuity as stone and mortar.
The technical challenge of reconstructing Derinkuyu's sounds involved accounting for the material properties of the cavernous walls, the shapes of chambers, and the specific types of sounds produced by human activity, such as conversation, footsteps, and rituals. Nas's expertise in interior architecture and acoustics was instrumental in simulating how these factors interacted in confined, underground spaces. She meticulously calibrated her models using physical measurements that reflect the real-world reverberation and sound diffusion characteristics unique to the subterranean urban context.
Underlying this research is a fundamental appreciation of the acoustic ecology of human settlements. Sound is not simply noise but an environmental parameter that shapes perception, behavior, and social interaction. In Derinkuyu, this was amplified by the enclosed nature of the city, creating acoustic signatures that would have affected everything from privacy to security. Understanding such ancient soundscapes broadens the scope of architectural and archaeological inquiry, integrating sensory experiences that have been largely silent in historical reconstructions.
Looking ahead, the virtual soundscape models of Derinkuyu open new vistas for education, tourism, and heritage conservation. Imagine walking through an ancient underground space while hearing the whispers, chants, and ambient sounds as they would have existed a millennium ago. Such immersive experiences deepen engagement and facilitate a more holistic appreciation of archaeological sites, bridging the divide between past and present. Nas's work stands at the forefront of this interdisciplinary movement, marrying technology and cultural history in innovative, impactful ways.
In sum, the exploration of Derinkuyu's underwater soundscape not only enriches our understanding of this ancient marvel but also paves the way for future investigations into how sound shapes human environments, past and present. Sezin Nas's research challenges existing paradigms, reminding us that the city is not merely a collection of stones but a resonant space shaped by the interaction of architecture, acoustics, and human experience beneath the earth's surface.
Subject of Research: Acoustic environment and soundscape reconstruction of the ancient underground city of Derinkuyu