Kategorie: ‘Acoustic simulation’
Sacred Sound: The acoustic reconstruction of no longer existing spaces
The project Sacred Sound – Sacred Space, led by musicologist Prof. Stefan Morent of the University of Tübingen, deals with the acoustics of sacred spaces as they existed and were used many centuries ago. In cooperation with IHTA, this project uses simulations to reconstruct, for example, the acoustics of the abbey church of Cluny III in order to auralize the liturgical chants of the medieval monks. Cluny III existed between 1130 and 1790 and was the largest church in the world until the construction of St. Peter’s Basilica in Rome.
Based on the room acoustic simulations, medieval choir chants were performed and recorded in IHTA’s laboratories by the ensemble Ordo Virtutum. During the recordings, the singers were presented with the reflections of the virtually reconstructed church space in real time. In further steps of the project these recordings will be analyzed musicologically in order to investigate the influence of the architecture on the musical performance.
Parts of the project were recently documented by the SWR in a radio (116 min.) and a TV report (20 min; both in German language).
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- Remnants of Cluny III (Foto: CC0, pxhere.com)
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- 3d model of cluny III. Black and dark grey parts show the still existing remnants of the church (Picture: Lukas Aspöck, CC-BY 4.0)
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- Ray Tracing simulation in the acoustic 3d model of Cluny III (Picture: Lukas Aspöck, CC-BY 4.0).
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- Simulated (and measured) reverberation times for the remnants and the full church (Picture: Lukas Aspöck, CC-BY 4.0).
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- Ensemble Ordo Virtutum during the recording session at the hemi anechoic chamber at the Institute (Picture: Lukas Aspöck, CC-BY 4.0).
Thanks for everyone at IHTA who supported this project. Thanks also to the Visual Computing Institute for helping out with the aixCAVE system and to the company Sennheiser for providing microphones for the recording sessions!
The ITA-Toolbox COMSOL interface
Acoustic simulations become a more and more important toolset for industry and research. For a few years now, our institute uses COMSOL Multiphysics for numerical simulations, e.g. FEM and BEM, in various fields of acoustics. For proper processing of simulation results, we usually rely on MATLAB and the ITA-Toolbox. Although COMSOL provides a MATLAB interface (LiveLink), using this for advanced processing is not straightforward. With this in mind, a user-friendly interface between the ITA-Toolbox and COMSOL was designed.
Key features
- Starting the COMSOL server and connecting Matlab
- A rich class structure representing a COMSOL model and its model nodes (geometry, physics, …)
- Evaluation of FEM / BEM results at arbitrary points using the itaResult format without writing the results to hard disk
- Quickly applying complex-valued, frequency-dependent data to COMSOL model (itaResult -> COMSOL interpolation)
Class structure of the ITA-Toolbox COMSOL interface
The class structure makes the usage of this interface intuitive and easily extendable. Similar to the actual COMSOL model, the itaComsolModel class contains nodes representing the geometry, physics, study and so on. Each node comes with functions to interact with the respective node. However, the current toolset also allows applying significant changes your model using a single line of Matlab code. For example, the user can apply a user-defined impedance to a pre-defined boundary selection or create a monopole source with a user-defined frequency response. In this case, multiple of those nodes are modified (e.g. geometry and physics).
If you are interested, the interface is part of the ITA-Toolbox, that can be downloaded or cloned from our Git repository. The related files can be found in the folder “ITA-Toolbox\applications\SoundFieldSimulation\Comsol\”. This also contains a set of small demos for getting started.
