Paris' Cathedral of Notre Dame has a ghost orchestra that is always performing, thanks to a sophisticated, multidisciplinary acoustics research project.
In the project, computer models use recordings from a live concert held at the cathedral and detailed room acoustic simulations to produce a novel type of audience experience: a virtual recreation of the live performance using spatial audio and virtual reality.
Researchers reproduced the recordings using computerized acoustical data and enhanced it with computer-generated virtual navigation -- 3-D visualizations made with immersive architectural rendering that float the viewer through the complex acoustics of the acclaimed medieval gothic cathedral.
Combined, the multimodal sound and image footage of the ghost orchestra produce a spectral tour to the sounds of the 19th century opera "La Vierge" -- The Virgin -- performed live during the 2012-2013 concert season to celebrate the Cathedral's 850th anniversary.
Multimodal virtual reality integration is central to the project's significance, said Brian F.G. Katz, lead investigator at the Institute Jean Le Rond d'Alembert, Pierre and Marie Curie University, in Paris.
"3D-audio is the hot topic today in virtual reality (VR) that is currently a very active subject in both academic and industrial research," Katz said. "With the commercialization of affordable VR systems -- the cheapest allowing for VR on smartphones -- spatial audio is rapidly immerging from the laboratory."
The next stage in spatial audio is personalized audio rendering that involves being able to adjust the rendering to match one's individual head and ear details.
"The importance of multimodal interactions, how visual and auditory cues balance in spatial perception, is key to VR and the sense of immersion, of being 'in' the VR world," Katz explained.
He envisions many applications emerging from the investigation.
The study was presented during Acoustics '17 Boston, the third joint meeting of the Acoustical Society of America and the European Acoustics Association held in Boston, Massachusetts.