ABOUT THE PROJECT
SOUND AS INTANGIBLE HERITAGE: PRESERVING THE ACOUSTICS OF CATHEDRALS IN THE UNITED KINGDOM
1st October 2018 – 30th September 2020 (24 months)
European Commission, Research Executive Agency
Type of action
Marie Skłodowska-Curie Actions, Standard European Fellowships
This multidisciplinary project aims to preserve the acoustics of four English cathedrals, which represent the diversity of this group of heritage buildings, by characterising their acoustic behaviour through impulse response measurements as well as by recreating their sound environment throughout history using computer models. Virtual acoustic techniques are applied to provide a simulation of the aural experience within the buildings at different points in history, including extracts of speech and music pieces that were part of liturgical or cultural celebrations. Moreover, listening tests are conducted to assess the acoustical perception in cathedrals. This fellowship will develop the applicant’s skills in virtual acoustics, sound design, and the use of new technologies for the study and dissemination of acoustical heritage, while at the same time the fellow’s technical background in acoustic engineering provides opportunities for knowledge transfer to the host institution. The project’s innovative approach will bring economic and social benefits to the EU by promoting and enriching heritage tourism, and by making the acoustical heritage of cathedrals widely accessible through the auralisations. The importance of sound as intangible cultural heritage will be disseminated to the general public through talks in festivals, public exhibitions and workshops. It will also result in several journal publications and conference papers The project will encourage international collaboration networks in the field of heritage acoustics.
The aim of this project is to study, preserve and disseminate the acoustical heritage of the cathedrals of York, Ely, Bristol and Ripon. The historical classification, the ground plan typology as well as the architectural style were considered to make the selection. This overall goal is tackled through the following objectives: (O1) to complete advanced training on recording techniques and the creative use of sound design; designing and conducting listening tests; public engagement and dissemination strategies; and project management and leadership in order to (O2) analyse the current acoustics of the chosen cathedrals, to preserve their sound through RIR as well as set a procedure transferable to other heritage buildings of similar characteristics around Europe; (O3) use computer models to simulate and analyse the acoustics of these cathedrals throughout the centuries; (O4) conduct dry recordings of speech and music extracts of the liturgy or cultural events that occurred at each cathedral, to generate perceptually valid auralisations; (O5) conduct listening tests to compare the objective results to the subjective experience and to analyse both the subjective perception and listening expectations of cathedral acoustics (e.g. to assess the preferred value of reverberation time, analysing whether it varies depending on the type of liturgy or music they are listening to); and (O6) disseminate findings within academia and the heritage sector, and to conduct public engagement events.
The project’s methodology designed to reach these goals consists of the following steps:
Step_1-Historical study of the cathedrals: gathering historical and technical information to document the transformation of the space over the years from an architectural point of view, as well as the liturgical or cultural events that take or have taken place in each cathedral, which may involve changes in the decoration or ephemeral assemblies, different types and/or locations of sound sources, and variations in the location and/or density of listeners.
Step_2-Dry recordings: selection of extracts of speech and music pieces that represent the cultural and liturgical use of the cathedrals over the centuries to be recorded in an anechoic chamber.
Step_3-Measurements of RIR: at each site, receiver/listener points are distributed throughout the congregation area. Sound source positions are chosen to reflect current and past uses of the space. At each source-receiver combination, RIR are measured by using Sounfield microphones and a dummy head. ISO 3382-1 is used as a reference to measure the RIR and to calculate the acoustic parameters.
Step_4–Initial simulation models: a computer model of each cathedral is generated using a 3D modelling application (SketchUp). They are then imported into the acoustic simulation software (CATT-Acoustic) where acoustic properties are assigned to each surface of the model and then calibrated using the RIR measured on site through an iterative comparative process.
Step_5-Auralisation of virtual environments using measured and simulated RIR: dry recordings are convolved by using specialised software tools.
Step_6-Subjective evaluation: Listening tests are conducted to determine the reliability of the auralisations, as well as to assess the acoustic perception within the cathedrals. The tests consist of a set of predefined questions on the perceived reverberation time and speech intelligibility, among others, involving several reproductions of each dry recording: as it was recorded in the real space; auralised with the measured RIR; auralised with the simulated RIR.
Step_7-Modified simulation models: the calibrated initial models are modified to simulate hypothetical scenarios based on research findings such as the presence of a large audience. Architectural changes are also simulated to recreate their acoustics in the past.
COLLABORATORS / SUPPORTERS
Bristol cathedral is one of the English cathedrals included in the project. They kindly agree to collaborate by giving us access to the space in order to carry out the acoustic measurements. Several cathedral members, all of them experts in different fields, also help us by providing valuable information and sharing personal experiences.
The Centre for the Study of Christianity and Culture is based at the University of York, UK. They share their research findings and interactive resources regarding English cathedrals. C&C connections with the cathedrals included in the project have been key for us to start collaborations with them.
TEP 130: Architecture, Heritage and Sustainability: Acoustics, Lighting, Optics and Energy, is a multidisciplinary research group of attached to the University Institute of Architecture and Construction Sciences (IUACC) of the University of Seville (Spain). The project is nourished with their broad experience in heritage acoustics. Our collaboration also include sharing their research findings on the acoustics of Spanish cathedrals, and specific resources to be used in our research.
Ripon cathedral is one of the magnificent cathedrals which are part to the Cathedral Acoustics project. They expressed their interest to join the project, giving us the authorisation to perform the acoustic measurements. They also collaborate with key information for the project's development.
The collaboration of the Audio and Acoustic Lab of the Electronic Engineering Department is very valuable. Their members contribute with their broad experience in signal processing, acoustic modelling, and psychoacoustics. Having access to their equipment and facilities, such as the anechoic chamber, is also key for the development of the project.