A silent city? Such a thing does not exist! In cities, people grate and scratch, meld together or tear materials, and shout at each other; the cries of animals mingle with the sounds of the environment. Yet most 3D reconstructions of the historical past are often silent—just the opposite of the Bretez Project, which has been created around sound.

This virtual model reproduces Paris in the second half of the eighteenth century – a Paris that has completely disappeared today. The purpose of this project was to create a matrix in order to generate 5D models of towns in the past, regardless of time and place. But what is a 5D model? It is a 3D model (length, width and height), where you can move in the first person (4th dimension) and where one of the senses is integrated – in our case sound.

Origins and Description of the Model

The Bretez Project was born after experiencing ‘love at first sight’ for the Turgot map, created between 1734 and 1739 by the geographer-engineer Louis Bretez. This map is in cavalier perspective, made of twenty-two sheets etched in intaglio. The ensemble presents a very detailed vision of Paris, in which paradoxically the Seine River with its many boats is much more alive than the city. These map boards provide further proof, if any were needed, that the river is a vital axis for the urban economy. Yet it is also a major axis of very rich sounds, leading us to question how to reconstruct historically accurate soundscapes, and not just some vague idea of what it might sound like.

In this spirit, the main destination of this sound model are museums, which does not prevent the research from being rigorously scientific. In fact, these reconstructions enable us to test hypotheses or answer questions that don’t have immediate solutions – such as the impact of acoustics on the whether people could hear sermons or religious songs during processions.

Since it is not yet possible to reconstruct all of Paris due to its size, the choice was made to focus on a twenty-five hectare area around the present Place du Châtelet:

• the Apport of Paris (that is, the market square, the Grand Boucherie and the Grand Châtelet, one of the prisons of the time);
• the pont au Change;
• the rue de la Pelleterie;
• the pont Notre-Dame (and its water pump);
• the rue and the quai de Gesvres and its covered market passage.

Why choose this area? Simply because it was the beating heart of Paris: there were merchants (at the Apport, around Châtelet, in the covered passage of the Quai de Gesvres, the two bridges), an important jurisdiction (Grand Châtelet as a prison and government building), and craftspeople working with leather (rue de la Pelleterie). These characteristics each generate completely different soundscapes and acoustics, thus taken together they include nearly eighty percent of the visual and sound scenarios present in eighteenth-century Paris.

Hearing the Past

While it may be easy to reconstruct a visual 3D, how do you successfully transform this model into a 5D version? First, you must choose a 3D renderer. We chose to use one from a video game engine, UDK. This type of software allows you to view artwork on a variety of media (immersive or not, fixed – such as terminals for example – or nomad – smartphone or tablet, etc.). The goal was to meet the demands of museums, who often had issues with multimedia technologies becoming obsolete too quickly. Once the issue of moving around in the model was solved, only the problem of sound remained.

This kind of historical soundscape reconstruction had never been done before. Of course, there is sound design (often the work of a composer who offers a sound design that is often not very historically accurate). There are also sound-effect engineers who produce sound environments or noises for a film: in other words, sound that often amplifies events to make us feel them more strongly. But these two jobs do not meet the high standards demanded by making an historical sound model for museums. To do this, we must call on archeology of soundscapes.

Like a ‘traditional’ historian or archaeologist, soundscape archaeologists rely on the same methodologies and follows the same rigorous standards in order to meet various needs of the periods covered by the reconstruction. While searching for clues, they cross-check the data in order to create a sound image of the past, while remaining aware that it is only a plausible hypothesis, since primary sources for sound do not exist.

For the Bretez Project, the sound reconstruction was done at the same time as the visual reconstruction. The work was divided into three major phases.

The preparatory phase was undoubtedly the longest and required the cooperation of multiple experts in the humanities and social sciences. Everyone participated in collecting evidence because each source, whether visual (engravings, paintings, everyday objects) or textual (literature, cards, police registers, notarized documents, etc.), is packed with information needed to make the soundscape model. To this end, analysis grids were created, which served as a sort of ‘particle filter’ for information related to sound, and also gave indications about the soundscapes and their cycles. The entire corpus of documentation was entered into a database, the only tool that can handle a great deal of information regardless of the medium.

Constructing a Plausible Soundscape

The data were then positioned on different maps according to their type. The differentiation obtained was the result of the characteristics of the acoustic events (such as sound prints, atmosphere, sounds, or noises), qualifying them (dry acoustics, reverberations, or closed or open spaces) and their type (animals, human activity, or nature sounds). By assembling them, we were able to create a plausible soundscape by giving it depth and density; it also revealed possible listening scenarios to help the ear identify sounds. The next step need to match what was found in the sources with sounds that still exist today (noise, sounds, or ambiances).

For example, for the trades, we consulted Diderot’s Great Encyclopedia to know the tools used at that time. Then we checked whether there were artisans (especially those working to protect the heritage of arts and crafts) still using those tools today. Only after this long phase of research were we able to start working on the sound material itself.

Designing the Sound

For the soundscape archaeologist, the final phase makes the initial research ‘readable’: the sound design. A recording campaign was launched with craftspeople who kindly agreed to play the game. The sound files were cleaned and formatted to form loops. If necessary, they were also worked with to form specific soundscapes. Each sound was initially neutralized and then, when placed in the model, was re-contextualized, especially according to the acoustics of the places involved.

As shown in the following illustration, the positioning also had to be done spatially. Taking this into account enabled us to position sounds like that of the Seine River, the sound print, in the lower part of the model and sounds like the call of birds in its upper part. Only after these and many other processes could the future walker visit the Châtelet quarter and delve into its soundscapes.

Transdisciplinary par excellence, the Bretez project draws on the knowledge and expertise of researchers from complementary disciplines, which is showcased differently. For example, quantitative historians helped precisely situate craftspeople, and historians of urban planning and Paris enabled a highly-detailed visual reconstruction thanks to textual and graphic references that designers used to build the model.

The soundscape archeology relied on all of this collective work to meet its goal of reconstructing soundscapes and environments. Innovating by providing a layer of senses to a 3D model, the project also enables ‘movement’ in virtual space. These aspects (immersion and movement) enable researchers in fields such as history or archeology to simulate situations by taking into account the acoustic characteristics of places and re-contextualizing events precisely.

Through the senses, this innovative approach to history offers a new social reading of the city and its rhythms. It highlights the distance that exists between our own perceptions of time (particularly the slow time of history compared with our hurried world today). Thus, researchers now have at their disposal a tool that enables findings by reconstitution, not supposition, which provides tangible responses to confirm or deny what were previously hypotheses.

Crédits image à la Une : CC Wikimedia Commons Raguenet

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