Journal of Cultural Heritage 34 (2018) 151–158 Available online at ScienceDirect www.sciencedirect.com Case Study The aesthetics of the Bayreuth Festspielhaus explained by means of acoustic measurements and simulations Dario D’Orazio ∗ , Simona De Cesaris , Federica Morandi , Massimo Garai Department of Industrial Engineering, University of Bologna, Viale Risorgimento 2, 40128 Bologna, Italy article info Article history: Accepted 2 March 2018 Available online 16 April 2018 Keywords: Room acoustics Opera house Wagner Auralisation abstract The Bayreuth Festspielhaus (BF) is unique; the theatre was conceived by Richard Wagner to host the complex of Ring and it was opened in 1876. After this date, the BF played a key role in the development of the modern opera house and no other opera house is so discussed among non acousticians for its acoustics. Some solutions applied for the first time in this theatre influenced later opera houses: the position of all seats within the line of sight of the stage, the dimming of the lights during representations, the double proscenium arch and–the most relevant one–the use of a deep orchestra pit (mystic gulf). However, in spite of the worldwide fame of the BF, the values assumed by the main room acoustics criteria in this hall have been reported and analysed in few works. The aim of the present work is to analyse the key role played by BF in the history of the opera basing on acoustic measurements and then propose tools for an immersive virtual experience of this space. All the main acoustic room criteria have been extracted and commented taking into account the peculiarity of the Wagnerian opera. Measured criteria have been related to the subjective impressions reported in the non technical literature. Furthermore, a numerical model of the theatre has been created. The model was calibrated by using the measured room criteria, following state-of-the-art techniques. A whole orchestra (105 musicians) plus singers (3 singers and a choir of 10 persons) was simulated on a computer. The present and the original acoustics of the hall were recreated by rendering binaural room impulse responses (BRIRs) for three listener positions in the audience. These tools allow to experience the Wagner’s idea of a “new opera” from a perceptual point of view. The CAD model and the simulated BRIRs of the BF are freely available for academic uses. © 2018 Elsevier Masson SAS. All rights reserved. 1. Introduction When musicians, architects and acousticians are asked to indi- cate a turning point relative to the evolution of opera theatre, the Festpielhaus in Bayreuth is often their first answer. This opera house is not just a building, for its architectural and acoustical projects blend together to convey to the audience the unique expe- Abbreviations: BF, Bayreuth Festspielhaus; BRocc , Bass ratio; BRIR, Binaural room impulse response; BQI, Binaural quality index, it is defined by the mathematical formula 6; C80, Sound clarity, it is defined by the mathematical formula 1; dB, deci- bel, measurement unit of a logarithmic scale of sound energy; EDT, Early Decay Time; G, Sound strength, it is defined by the mathematical formula 3; GA, Sim- ulation techniques based on geometric approximation of the acoustic field; IACC, Interaural Crosscorrelation Coefficient, it is defined by the mathematical formula 4; IR, Acoustic impulse response of the hall; JND, Just noticeable difference; LEV, Listener envelopment, it is defined by the mathematical formula 7; Ts , Centre time, it is defined by the mathematical formula 2; T30, Reverberation time. ∗ Corresponding author. E-mail address: dario.dorazio@unibo.it (D. D’Orazio). rience of participating to the representation of the Wagnerian opera. The BF is the result of a long development process in which several subjects contributed in different ways to the Wagner’s intention of building a “new theatre for the German opera”. The seed idea for the development of such performance space may be dated back to 1836, when Richard Wagner took up the role of musi- cal director in Riga (Latvia) and conducted in a temporary wooden summer theatre. Wagner spotted three key factors of this expe- rience: “Firstly the steep rising stalls, rather than amphitheatre, secondly the darkness of the auditorium, and thirdly the surpris- ingly deep orchestra pit. If he ever succeeded in building a theatre to his own plans, he would have regard to these three features” [1]. Then in Paris (1840), Wagner experienced the new stage effects which enriched the French representation at that time, e.g. the Dio- rama of Daguerre for the finale of Auber’s opera La muette de portici, reprised in the Brünnhilde immolation of the Götterdämmerung [2]. During his exile in Zurich and Dresden, Wagner [3] wrote sev- eral meditations about the decline of Western Civilisation and the corruption of the arts: “its aesthetic pretext is the entertainment https://doi.org/10.1016/j.culher.2018.03.003 1296-2074/© 2018 Elsevier Masson SAS. All rights reserved.