Acoustic Reconstruction of Eszterháza Opera House Following New Archival Research

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Article Acoustic Reconstruction of Eszterháza Opera House Following New Archival Research

Lamberto Tronchin 1,* , Francesca Merli 1 and Marco Dolci 2

1 Department of Architecture, University of Bologna, 47521 Cesena, Italy; [email protected] 2 Gruppo C.S.A Spa, via al Torrente 22, 47923 Rimini, Italy; [email protected] * Correspondence: [email protected]

Received: 20 October 2020; Accepted: 25 November 2020; Published: 9 December 2020

Abstract: The Eszterháza Opera House was a theatre built by the will of the Hungarian Prince Nikolaus Esterházy in the second half of the 18th century that had to compete in greatness and grandeur against Austrian Empire. The composer that inextricably linked his name to this theatre was Haydn that served the prince and composed pieces for him for many years. The Opera House disappeared from the palace complex maps around 1865 and was destroyed permanently during the Second World War. This study aims to reconstruct the original shape and materials of the theatre, thanks to the documents founded by researchers in the library of the Esterházy family at Forchtenstein, the Hungarian National Library, and analyze its acoustic behavior. With the 3D model of the theatre, acoustic simulations were performed using the architectural acoustic software Ramsete to understand its acoustical characteristics and if the architecture of the Eszterháza Opera House could favor the Prince’s listening. The obtained results show that the union between the large volume of the theatre and the reﬂective materials makes the Opera House a reverberant space. The acoustic parameters are considered acoustically favorable both for the music and for the speech transmission too. Moreover, the results conﬁrm that the geometry and the shape of the Eszterháza Opera House favored the Prince’s view and listening, amplifying onstage voices and focusing the sound into his box.

Keywords: Eszterháza Opera House; acoustic simulation; room acoustics; cultural heritage; virtual 3D acoustics

1. Introduction The research on the acoustic characteristic of historical buildings is becoming more and more frequently a theme on which researchers focus their attention, because acoustic is more often considered a cultural heritage and an important feature of several ancient important buildings such as Opera House [1–5]. To analyze the sound field of Opera House, in situ measurements are performed, placing a lot of receivers in the hall and some sound sources on stage and orchestra pit [6,7] and recording monaural and binaural impulse responses (RIRs). Finally, measured impulse responses are used for the calculation of the room acoustic parameters. Unfortunately, a lot of public and private theatres and their intangible cultural heritage, i.e., the acoustics, were devastated and demolished during past fires, wars, and natural disasters [8–10], such as for Eszterháza Opera House, a theatre built by Prince Nikolaus I Esterházy was destroyed during the Second World War. For this reason, computer simulation became an essential tool for the reconstruction of the acoustic field of ancient and destroyed theatres. The creation of a virtual acoustic model of a theatre allows to generate a signal and process the impulse response, from which it is possible to analyze the acoustic features and acoustic parameters of the reconstructed historical building. The 3D model of the historical Eszterháza Opera House was realized to rediscover the acoustics of this theatre and to analyze the position occupied by Prince Nikolaus I Esterházy during performances.

Appl. Sci. 2020, 10, 8817; doi:10.3390/app10248817 www.mdpi.com/journal/applsci Appl. Sci. 2020, 10, x FOR PEER REVIEW 2 of 16

The 3D model of the historical Eszterháza Opera House was realized to rediscover the acoustics Appl. Sci. 2020, 10, 8817 2 of 15 of this theatre and to analyze the position occupied by Prince Nikolaus I Esterházy during performances. The second section illustrates a brief history of Eszterháza Eszterháza Opera House reporting some figures ﬁgures and drawings ofof thethe originaloriginal shape. shape. The The third third section section explains explains the the assumptions assumptions considered considered during during the thedevelopment development of the of the 3D model3D model and and scenarios. scenarios. Finally, Finally, the the results results and and conclusions conclusions are are discussed discussed in the in thelast last paragraphs. paragraphs.

2. The The History History of of Eszterháza Eszterháza Opera House EszterházaEszterháza is aa palacepalace locatedlocated in in Fert˝odtown, Fertőd town, a a location location in in northwestern north-western Hungary Hungary born born from from the theunion union oftwo of two towns towns Eszterh Eszterházaáza and and Süttöra Süttöra in in 1950. 1950. The The palace palace was was built builtin in RococRococòò stylestyle and was called the Hungarian Versailles. In 1720, Prince NikolausNikolaus EsterhEsterházyázy was used to spendspending much much of his of histime time in a in hunting a hunting lodge lodge called called Süttör, Süttör, which which was was designed designed by Antonby Anton Erhard Erhard Martinelli. Martinelli. In 1768, 1768, the the Prince Prince permanently permanently settled settled in inthe the hunting hunting lodge lodge that that was wasrenamed renamed “Eszterháza” “Eszterh áandza” becomeand become the nucleus the nucleus around around which which Eszterháza Eszterh Palaceáza Palace was built. was In built. 1763, In Nikolaus 1763, Nikolaus Esterházy Esterh startedázy thestarted construction the construction of the palace, of the palace, including including the Oper thea OperaHouse, House, which which had to had compete to compete in greatness in greatness and grandeurand grandeur against against the theAustrian Austrian imperial imperial residences. residences. The The Prince Prince entrusted entrusted the the construction construction of of the palace to the architect Melchior Hefele, and the new palace had to be an extension of a pre-existing hunting lodge. SinceSince 1768,1768, thethe constructionconstruction of of the the ﬁrst first Opera Opera House House was has completed been completed and many and musical many musicalentertainments entertainments were performed. have been However, performed. the Opera However, House burned the Opera down inHouse November burned 1779 down and was in Novemberreplaced by 1779 a second and Operawas replaced House, andby a the second construction Opera House, of the second and the theatre construction continued of from the second 1779 to theatreFebruary continued 1781 [11 ]from (Figure 17791). to February 1781 [11] (Figure 1).

Figure 1. DrawingDrawing of of the the second second Eszterháza Eszterháza Opera Opera House. House. Enlarged Enlarged detail detail of of Antonio Antonio Pesci’s Pesci’s painting painting depicting thethe south south facade facade of theof the palace–Modified palace–(Építés (Ézetipíté szetiMúzeum—Museum Múzeum—Museum of Ar ofchitecture, Architecture, Budapest). Budapest).

The new,new, reconstructed reconstructed Opera Opera House House was was inaugurated inaugurated with with the performance the performance of Haydn, of Haydn, La fedelt Laà fedeltàpremiata. premiata. The construction The construction phases of phases the second of the Opera second House Opera and House the materials and the usedmaterials for its used realization for its wererealization tidily were registered tidily by registered the Esterh byázy the administration. Esterházy administration. A document A entitled document “Extent entitled of the “Extent masonry of workthe masonry regarding work the regarding new playhouse” the new of playhouse” the court engineer of the court Michael engineer Stöger Michael conﬁrms Stöger that the confirms new theatre that wasthe new built theatre on the was site thatbuilt had on the been site previously that had occupiedbeen previously by the ﬁrstoccupied Opera by House. the first Prince Opera Nikolaus House. Princeordered Nikolaus that the secondordered theatre that the had second to be theatre very similar had to in be dimensions very similar to Schönbrunnin dimensions theatre. to Schönbrunn From the theatre.examination From ofthe the examination drawings ofof thethe Operadrawings House of the dated Opera 1784 House (Figure dated2) and 1784 recent (Figure pictures 2) and ofrecent the picturesSchönbrunn of the theatre Schönbrunn (Figure theatre3), one can(Figure discover 3), one that can some discover of the that main some characteristics of the main ofcharacteristics the current oflayout the current of Schönbrunn’s layout of Schönbrunn’s interior resemble interior the historicalresemble planthe historical of Eszterh planáza: of the Eszterháza: oval hallwith the oval a raised hall withgallery a raised on three gallery sides, on in three which sides, the in central which section, the central opposite section, to theopposite stage, to was the reserved stage, was to thereserved Price tofamily. the Price The Royalfamily. box The was Royal supported box was by supported stone columns by stone and coveredcolumns by and a canopy covered and by surrounded a canopy and by two side-boxes. At Eszterháza Opera House, the Royal box was connected with the galleries and with such an arrangement, the Prince could leave his Royal box and visit his visitors and his court sitting Appl. Sci. 2020, 10, x FOR PEER REVIEW 3 of 16

surrounded by two side-boxes. At Eszterháza Opera House, the Royal box was connected with the galleriesAppl. and Sci. with 2020, 10 such, x FOR an PEER arrangement, REVIEW the Prince could leave his Royal box and visit3 ofhis 16 visitors and his court sitting anywhere on the gallery level. The main difference between the two theatres was to the Price family. The Royal box was supported by stone columns and covered by a canopy and Appl.that Sci. the2020 surroundedEszterháza, 10, 8817 by Opera two side House-boxes. was At Eszterháza an independent Opera House building, the Royal separated box was from connected the main with palacethe and3 of 15 it was connectedgalleries and to w theith suchmain an palace arrangement, by only the a Prince short could walk leave through his R oyalthe boxornamental and visit hisgarden, visitors whereas the theatreand ofhis Schönbrunn court sitting anywhere was built on into the gallery a wing level. of the The palace. main difference between the two theatres is anywherethat on the Eszterháza gallery level. Opera TheHouse main was an di ﬀindependenterence between building the andtwo it was theatres connected is to that the themain Eszterh áza Opera Housepalace was by only an independenta short walk through building the ornamental and it was garden, connected whereas the to theatre the main of Schönbrunn palace by was only a short built into a wing of the palace. walk throughDressing-rooms the ornamental garden, whereas the theatre of SchönbrunnRoyal was Box built into a wing of the palace.

Gallery

Dressing-rooms Royal Box

Stage StallsGallery

StallsGallery Stage

Gallery

(a)

Gallery Stage Gallery Stage

StallsStalls

(b))

Figure 2. Drawings of Eszterháza Opera House in 1784: (a) plan of the theatre and (b) longitudinal FigureAppl.Figure Sci. 2. 2.Drawings 2020 Drawings, 10, x FOR of of Eszterh EszterházaPEER REVIEWáza OperaOpera HouseHouse in 1784: ( (aa)) plan plan of of the the theatre theatre and and (b ()b longitudinal) longitudinal 4 of 16 section of the theatre–Modified [12]. sectionsection of of the the theatre–Modiﬁed theatre–[12]. [12].

GalleryGallery GalleryGallery Royal boxRoyal box

StallsStalls FigureFigure 3. Recent 3. Recent picture picture of the of the Schönbrunn Schönbrunn Theatre–Modiﬁed Theatre–Modified (copyright: (copyright: Schloϐ SchönbrunnSchönbrunn Kultur- Kultur-undund Betriebsges.m.b.H).

PrincePrince Esterh Esterházyázy allowed allowed commoners commoners to join to hisjoin noble his noble guests guests at performances at performances at Eszterhat Eszterháza,áza, but but withwith this this arrangement arrangement of the of theatre,the thea Eszterhtre, Eszterházaáza Opera Opera House House could could maintain maintain the old the order old oforder social of social separationseparation among among his guests. his guests. The composer The composer Haydn Haydn served served Prince Prince Nikolaus Nikolaus I from I 1762, from and 1762, between and between 1766 and 1790, the palace housed him as the composer of the prince, and he wrote the majority of his symphonies for the Prince’s orchestra. The regular opera seasons at the Eszterháza “opera factory” were first established in 1776, and the majority of Haydn’s opera productions were connected with the second opera house in the period from 1781 to 1790. The prince demanded two operas and two concerts every week, as well as chamber music every hour. The prince personally enjoyed playing the baryton (Viola di Bordone), for which Haydn created 175 compositions. The Opera House had several distinct features, such as a seat for the prince who had the best view, and the orchestra sat in front of the stage; there was no space for a conductor. The first performance of Joseph Haydn played in the Opera House was Lo speziale in 1768, followed by Le pescatrici in 1769 [13–15]. After Nikolaus’ death in 1790, none of the heirs wanted to live in Esterháza, and the theatre fell into disrepair and eventually disappeared from the palace complex maps around 1865. During the Second World War, the theatre was definitively destroyed, while the Palace has recently been restored, returning to its former glory (Figure 4).

Figure 4. View of restored Esterházy Palace [16]-Modified. The position of the Eszterháza Opera House is indicated with the white box.

Appl. Sci. 2020, 10, x FOR PEER REVIEW 4 of 16

Figure 3. Recent picture of the Schönbrunn Theatre–(copyright: Schloϐ Schönbrunn Kultur-und Betriebsges.m.b.H).

Prince Esterházy allowed commoners to join his noble guests at performances at Eszterháza, but Appl.with Sci.this2020 arrangement, 10, 8817 of the theatre, Eszterháza Opera House could maintain the old order of social4 of 15 separation among his guests. The composer Haydn served Prince Nikolaus I from 1762, and between 1766 and 1790, the palace housed him as the composer of the prince, and he wrote the majority of his 1766symphonies and 1790, for the the palace Prince’s housed orchestra. him as The the regula composerr opera of the seasons prince, at andthe heEszterháza wrote the “opera majority factory” of his symphonieswere first established for the Prince’s in 1776, orchestra. and the majority The regular of Haydn’s opera seasons opera productions at the Eszterh wereáza “operaconnected factory” with werethe second ﬁrst established opera house in in 1776, the andperiod the from majority 1781 of to Haydn’s 1790. The opera prince productions demanded were two connectedoperas and with two theconcerts second every opera week, house as inwell the as period chamber from music 1781 toevery 1790. hour. The The prince prince demanded personally two enjoyed operas andplaying two concertsthe baryton every (Viola week, di as Bordone), well as chamber for which music Hayd everyn created hour. The175 princecompositions. personally The enjoyed Opera playingHouse had the barytonseveral distinct (Viola di features, Bordone), such for as which a seat Haydn for the created prince 175who compositions. had the best view, The Opera and the House orchestra had several sat in distinctfront of the features, stage; suchthere as was a seat no space for the for prince a conduc whotor. had The the first best performance view, and the of Joseph orchestra Haydn sat in played front ofin the Opera stage; thereHouse was was no Lo space speziale for ain conductor. 1768, followedThe firstby Le performance pescatrici in of 1769 Joseph [13–15]. Haydn After played Nikolaus’ in the Operadeath in House 1790, was none Lo of speziale the heirs in 1768,wanted followed to live by in LeEsterháza, pescatrici and in 1769 the theatre [13–15]. fell After into Nikolaus’ disrepair death and ineventually 1790, none disappeared of the heirs from wanted the topalace live incomplex Esterhá za,maps and around the theatre 1865. fell During into disrepairthe Second and World eventually War, disappearedthe theatre was from definitively the palace complexdestroyed, maps while around the 1865.Palace During has recently the Second been World restored, War, returning the theatre to was its definitivelyformer glory destroyed, (Figure 4). while the Palace has recently been restored, returning to its former glory (Figure4).

Figure 4.4. ViewView of of restored restored Esterh Esterházyázy Palace Palace [16 ]-Modiﬁed.[16]. The position The position of the of Eszterháza the Eszterh áOperaza Opera House House is isindicated indicated with with the the white white box. box.

The main documents founded by researchers for updating the image of the Eszterháza Opera House derive from the Esterházy family library at Forchtenstein, the Hungarian National Library, and the materials consist of site plans, descriptions, inventories, cost estimates, administration decisions, and invoices concerning the construction process and materials. From the study of drawings, it becomes clear that the geometry and shape of the Eszterháza Opera House favored the position of the prince in every aspect. In fact, he enjoyed the ideal illusion of central perspective because his eyes were almost at the level with the vanishing point deﬁned by the slope of the stage.

3. Model of the Eszterháza Opera House for Geometrical Acoustic Simulations

3.1. The 3D Model of the Eszterháza Opera House The 3D model of the theatre was realized to reconstruct the acoustics of the Eszterháza Opera House, starting from the analysis of available literature and drawings dated 1784 and 1789 (Figures2 and5) . The two ﬁgures present an architectural discrepancy in the diﬀerent positioning of the lateral access stairs. Consequently, the most detailed version of the plan (Figure5) was used to create the base for the 3D model. Subsequently, the ground was integrated with the longitudinal section of the theatre (Figure2b). Appl. Sci. 2020, 10, x FOR PEER REVIEW 5 of 16

3. Model of the Eszterháza Opera House for Geometrical Acoustic Simulations

3.1. The 3D Model of the Eszterháza Opera House The 3D model of the theatre was realized to reconstruct the acoustics of the Eszterháza Opera House, starting from the analysis of available literature and drawings dated 1784 and 1789 (Figures 2 and 5). The two figures present an architectural discrepancy in the different positioning of the lateral access stairs. Consequently, the most detailed version of the plan (Figure 5) was used to create the Appl.base Sci.for2020 the, 103D, 8817 model. Subsequently, the ground was integrated with the longitudinal section of5 of the 15 theatre (Figure 2b).

Gallery

Stalls Stage Royal Box

Gallery

FigureFigure 5.5. Plan of the theatre made byby thethe mastermaster builderbuilder JosephJoseph RingerRinger inin 17891789 fromfrom thethe NationalNational Archives-ModiﬁedArchives (Országos (Orsz Levéltár,ágos OL Lev T2éltá no.r, OL 1222, T2 no.Budapest). 1222, Budapest).

AA geometricalgeometrical model model including including 2175 2175 surfaces surfaces (3D Faces),(3D Faces), 3420 m34202 surface m2 surface area, and area, 5659 and m3 5659volume m3 wasvolume realized was inrealized AutoCAD in AutoCAD software, accordingsoftware, according to guidelines to ofguidelines previous of literature previous [17 literature]. During [17]. the phaseDuring of the drawing phase of of the drawing model, theof the images model, were the scaled images according were toscaled the “accordingklafter” measurement to the “klafter unit” presentmeasurement in the respectiveunit present documents. in the respective The “klafter documents.” is a historical The “klafter” unit of is length, a historical volume, unit and of the length, area usedvolume, in Central and area Europe, used 1 in Klafter Central= 18.965 Europe, m. To1 performKlafter = the 18.965 simulations, m. To perform a simpliﬁed the 3Dsimulations CAD model, a Appl.ofsimplified the Sci. Opera 2020 ,3D 10 House, CADx FOR wasPEERmodel createdREVIEW of the (Figure Opera 6House). was created (Figure 6). 6 of 16

FigureFigure 6. 6. TheThe 3D 3D model model of of the the Eszterháza Eszterháza Opera Opera House. House.

VeryVery detaileddetailed 3D 3D models models are knownare known to considerably to considerably increase increase computation computation time without time improving without improvingresults accuracy results [18 accuracy]. Consequently, [18]. Consequently, the theatre wasthe theatre modelled was by modelled representing by representing only the geometrical only the geometricalshape and signiﬁcantshape and elements, significant while elements, surfaces while having surfaces rich decorativehaving rich patterns decorative were patterns simulated were as simulatedﬂat planes. as Therefore,flat planes. duringTherefore, the during realization the realization of the model of the employing model employing 3D faces, 3D all faces, those all curved those curvedsurfaces, surfaces, such as thesuch arched as the openings, arched openings, the handrail, the and handrail, portions and of theportions slabs, haveof the been slabs, approximated have been approximatedwith polylines with to create polylines complex to create surfaces. complex The surfaces. purpose The was purpose to obtain was ato model obtain thata model was that as close was asas close possible as possible to reality to reality but at but the at same the same time time to not to takenot take into into account account those those elements elements that that produce produce a a minimal or irrelevant variation in terms of physical parameters. The AutoCAD layers were managed considering used construction materials (12 layers in total) because the architectural acoustic software is based on the response produced by the different materials in terms of absorption and scattering coefficients. Consequently, a material and coefficient were assigned to all the surfaces of the model through hypotheses formulated by visual inspection of the historical images: window frame, floor, wall, backrest chair, seat chairs, ceiling, curtains, and chandeliers. Subsequently, the 3D CAD model was exported in .dxf format and three acoustic simulations were performed to analyze the acoustic behavior of the theatre using the architectural acoustic software Ramsete [19,20]. Thanks to this software, it was possible to acquire acoustics parameters necessary to investigate the acoustic characteristics of the simulated theatre.

3.2. Assumptions and Acoustic Simulations In this study, the calibration of the model was not conducted, because the original Opera House was destroyed during the Second War World and, currently, it is possible to visit an auditorium that differs considerably from the original theatre. Consequently, to assign material properties, some consideration about the materiality of the original theatre was necessary. The absorption and scattering coefficients were attributed considering usual values from the literature [21,22], possibly combining them with those resulting from research on acoustic simulations of similar buildings [23]. Researches and some historical documents [11] confirm the similarity of Eszterháza Opera House with the Schönbrunn Theatre. The exterior walls of the building were considered made by masonry, while the interior of the hall was lined with a variety of materials including plaster along the walls and wooden parquet on the floors. The parapet of the balcony and the columns on walls were made by hard stone, whereas the timber ceiling structure supported painted plaster work in the main hall. Moreover, French windows were lined up along the gallery. From the analysis of historical references [11–16], it is Appl. Sci. 2020, 10, 8817 6 of 15 minimal or irrelevant variation in terms of physical parameters. The AutoCAD layers were managed considering used construction materials (12 layers in total) because the architectural acoustic software is based on the response produced by the different materials in terms of absorption and scattering coefficients. Consequently, a material and coefficient were assigned to all the surfaces of the model through hypotheses formulated by visual inspection of the historical images: window frame, floor, wall, backrest chair, seat chairs, ceiling, curtains, and chandeliers. Subsequently, the 3D CAD model was exported in .dxf format and three acoustic simulations were performed to analyze the acoustic behavior of the theatre using the architectural acoustic software Ramsete [19,20]. Thanks to this software, it was possible to acquire acoustics parameters necessary to investigate the acoustic characteristics of the simulated theatre.

3.2. Assumptions and Acoustic Simulations In this study, the calibration of the model was not conducted, because the original Opera House was destroyed during the Second War World and, currently, it is possible to visit an auditorium that differs considerably from the original theatre. Consequently, to assign material properties, some consideration about the materiality of the original theatre was necessary. The absorption and scattering coefficients were attributed considering usual values from the literature [21,22], possibly combining them with those resulting from research on acoustic simulations of similar buildings [23]. Researches and some historical documents [11] confirm the similarity of Eszterháza Opera House with the Schönbrunn Theatre. The exterior walls of the building were considered made by masonry, while the interior of the hall was lined with a variety of materials including plaster along the walls and wooden parquet on the floors. The parapet of the balcony and the columns on walls were made by hard stone, whereas the timber ceiling structure supported painted plaster work in the main hall. Moreover, French windows were lined up along the gallery. Once defined the materials of the theatre, the absorption and scattering coefficients were selected from the database accordingly with the values employed during the acoustic virtual reconstruction of the Theatre Ideale by Francesco Milizia and considering usual literature values [23–25]. Consequently, the defined materials and their absorption and scattering (s) coefficients were reported on a specific file as in Table1. For the audience, the values are higher than in other cases, since in that time, the spectators used to wear full skirts and wigs.

Table 1. Absorption and scattering coeﬃcients (s) for all the materials involved in the simulation. The scattering coeﬃcient is referred to 707 Hz.

Absorption Surface Materials s Reference (%) 250 500 1 2 4 Hz Hz kHz kHz kHz Adapted Wood (hall and ﬂoor) 27.4 0.100 0.080 0.080 0.100 0.100 0.05 [24] Lime plaster (hall and 33.5 0.230 0.240 0.240 0.250 0.340 0.50 [25] ﬂy tower) Marble (columns, half pilaster, 10.5 0.010 0.010 0.020 0.020 0.020 0.05 [25] and balustrade) Light wood (stage ceiling) 7.9 0.040 0.060 0.120 0.100 0.170 0.05 [24] Adapted Decorated stucco (hall ceiling) 12.6 0.340 0.360 0.360 0.380 0.400 0.05 [25] Curtains 0.4 0.120 0.350 0.450 0.380 0.360 0.05 [24] Glass (windows) 3.5 0.250 0.180 0.120 0.070 0.040 0.05 [24] Chandeliers 0.9 0.060 0.040 0.030 0.020 0.020 0.05 [24] Wooden chairs 3.4 0.040 0.060 0.120 0.100 0.170 0.05 [24] Adapted Audience 3.4 0.740 0.820 0.900 0.900 0.780 0.70 [23] Appl. Sci. 2020, 10, 8817 7 of 15

Two omnidirectional sources (A and B) were placed on the stage and the 106 receivers were uniformly distributed throughout the stalls and balcony (from R1 to R85 in the stalls and from R86 to R106 in the balcony), see Figure7. The signals were simultaneously emitted from the stage to simulate the performance of actors and musicians. Then, the architectural acoustic software made the energetic sum of the impulse response A and B. Once the total IR was obtained, the acoustic parameters wereAppl. calculated. Sci. 2020, 10, x FOR PEER REVIEW 8 of 16 Appl. Sci. 2020, 10, x FOR PEER REVIEW 8 of 16

Figure 7. Plan of sound source positions (red points) and 106 receiver positions (blue points). Figure 7. Plan of sound source positions (red points) and 106 receiver positions (blue points). Figure 7. Plan of sound source positions (red points) and 106 receiver positions (blue points). OnceOnce the the model model was was validated validated for for thethe emptyempty theatr theatree (Scenario (Scenario 1, 1,as asFigure Figure 8a),8 a),the theabsorption absorption coefficoefficientcientOnce of the ofthe the chairsmodel chairs waswas was modified validatedmodified tofor to simulate simulatethe empty the the presencetheatr presencee (Scenario of the of audience the 1, audienceas Figurein the hall in8a), the(Scenario the hall absorption (Scenario 2). The 2). The valuecoefficientvalue of of absorption absorption of the chairs coefficients coewasffi modifiedcients of the ofto chairs thesimulate chairs has the be has presenceen replaced been of replaced the with audience tissue’s with in cotissue’s theefficient, hall (Scenario coe as ffidonecient, 2). in The the as done in thevalueprevious previous of absorption study, study, that coefficients thatachieved achieved excell of theent excellent chairs results has [26]. results be enThe replaced [presence26]. The with of presence the tissue’s audience co ofefficient, the in the audience stalls,as done galleries, in in the the stalls, galleries,previousand Royal and study, Royal box isthat boximportant achieved is important to excell understand toent understand results whether [26]. The whetherit can presence negatively it can of the negatively affect audience the overall a inffect the the acousticsstalls, overall galleries, of acousticsthe of theandtheatre theatre Royal and andbox if it ifis involves itimportant involves variations to variations understand of the of room’swhether the room’s acoustics it can acoustics negatively parameters. parameters. affect The the sound overall The absorption soundacoustics absorption of the of the spectatorstheatrespectators and dependsif it involves on on posture,variations posture, clothing, clothing,of the room’s and and al acousticsso also occupation occupation parameters. density density The [27–29] sound [27 – and29absorption] andits value its of value wasthe was spectators depends on posture, clothing, and also occupation density [27–29] and its value was chosenchosen accordingly accordingly with with the literature literature [23]. [23 In]. the From last thesimulation, analysis Eszterh of historicaláza Opera references House 3D [ 11model–16], it is chosenwas reconstructed accordingly according with literature to the [23].plan Indated the last1784 simulation, (Figure 8b), Eszterh addingáza two Opera dressing House room 3D (6.50model m possible to state that Eszterháza Opera House had many capacities in its historical evolution, and it washigh, reconstructed 7.40 m wide, according and 5.80 mto long)the plan covered dated with 1784 li (Figureme plaster 8b), at adding the back two of dressing the stage room without (6.50 the m was nothigh,presence normally 7.40 of m the wide, used audience and in full5.80 in thecapacity,m long)main coveredhall and (Scenario indeed, with li3). theme chairsplaster wereat the not back always of the placedstage without in the galleries.the Therefore,presence the of simulations the audience werein the performed main hall (Scenario placing 3). about 200 chairs in the main hall.

(a) (b) (a) (b) Figure 8. The 3D model of the Eszterháza Opera House in Scenarios 1 and 2 (a), and the 3D model of FigureFigurethe 8. EszterházaThe 8. The 3D 3D model Opera model ofHouse of the the Eszterhin Eszterháza Scenarioáza 3 OperaOp (b).era House House in in Scenarios Scenarios 1 and 1 and 2 (a 2), (anda), andthe 3D the model 3D model of of the Eszterhthe Eszterházaáza Opera Opera House House in in Scenario Scenario 33 ((bb).). Acoustic simulations were carried out in the octave bands from 250 to 4 kHz, setting the relative humidityAcoustic at 50% simulations and temperature were carried at 20Celsius. out in the The octave IR definition bands from was 250 set to 1 4ms kHz, with setting the length the relative of 5 s. humidityThe main atacoustic 50% and parameters temperature defined at 20Celsius. in ISO 3382-1:2009 The IR definition [30] were was calculated, set 1 ms with and the lengthresults ofof 5the s. Thesimulations main acoustic are discussed. parameters The defined reverberation in ISO 3382-1:2009 was evaluated [30] werethrough calculated, reverberation and the time results (T10 of andthe simulations are discussed. The reverberation was evaluated through reverberation time (T10 and Appl. Sci. 2020, 10, 8817 8 of 15

In the last simulation, Eszterháza Opera House 3D model was reconstructed according to the plan dated 1784 (Figure8b), adding two dressing rooms (6.50 m high, 7.40 m wide, and 5.80 m long) covered with lime plaster at the back of the stage without the presence of the audience in the main hall (Scenario 3). Acoustic simulations were carried out in the octave bands from 250 to 4 kHz, setting the relative humidity at 50% and temperature at 20 Celsius. The IR deﬁnition was set 1 ms with the length of 5 s. The main acoustic parameters deﬁned in ISO 3382-1:2009 [30] were calculated, and the results of the Appl. Sci. 2020, 10, x FOR PEER REVIEW 9 of 16 simulations are discussed. The reverberation was evaluated through reverberation time (T10 and T30), whileT30), the while perceived the perceived reverberation reverberation was obtained was obta withined Early with Decay Early TimeDecay (EDT). Time The(EDT). clarity The perceivedclarity forperceived music was for relatedmusic was to the related parameter to the C80,parameter whereas C80, the whereas clarity the perceived clarity perceived for the speech for the was speech related towas the related parameter to the C50. parameter Moreover, C50. Moreover, the center the time, center strength, time, strength, and STI and (Speech STI (Speech transmission transmission index) wereindex) calculated. were calculated.

4.4. Results Results and and Discussion Discussion FiguresFigures9 and9 and 10 10 report report the the results results ofof severalseveral mo monauralnaural parameters parameters obtained obtained with with the the two two sound sound sourcessources on on the the stage stage forfor thethe theatretheatre inin ScenarioScenario 1, 1, Scenario Scenario 2, 2, and and Scenario Scenario 3. 3.First, First, the the effect eff ectof of occupancyoccupancy on on the the acoustical acoustical parameters parameters waswas investigated.investigated. The reverberation time time was was analyzed, analyzed, and and it appearsit appears that that Eszterh Eszterházaáza Opera Opera House, House, with with its greatits great volume volume and and highly highly reflective reflective materials, materials, favors favors high reverberationhigh reverberation times attimes mid-frequency. at mid-frequency. Slightly Slightly lower dilowerfferences differences between between unoccupied unoccupied and occupied and theatreoccupied appeared theatre for appeared EDT and for T10 EDT possibly and T10 as possibly a consequence as a consequence of the big airof the volume big air and volume the contribution and the ofcontribution unchanged earlyof unchanged reflections, early whereas reflections, in Scenario whereas 3, in the Scenario theatre 3, was the less theatre reverberant was less thanreverberant the others than the others due to smaller air volume. due to smaller air volume.

Figure 9. Averaged values of the simulated acoustic parameters (Early Decay Time (EDT) and T10) for Figure 9. Averaged values of the simulated acoustic parameters (Early Decay Time (EDT) and T10) the theatre in Scenario 1 (empty theatre), Scenario 2 (with the audience), and Scenario 3 (3D model for the theatre in Scenario 1 (empty theatre), Scenario 2 (with the audience), and Scenario 3 (3D model reconstructed according to the plan dated 1784 in unoccupied condition). reconstructed according to the plan dated 1784 in unoccupied condition). The acoustic characteristic of the Opera House in terms of music perception is important since The acoustic characteristic of the Opera House in terms of music perception is important since Haydn’s symphonies and chamber music was listened by Prince Nikolaus I. Haydn’s symphonies and chamber music was listened by Prince Nikolaus I. As can be seen from the graphs, the center time spans from 88 ms (with dressing rooms on the As can be seen from the graphs, the center time spans from 88 ms (with dressing rooms on the stage) to 97 ms (without the audience) at 1 kHz, while the parameter C80 assumes values between stage) to 97 ms (without the audience) at 1 kHz, while the parameter C80 assumes values between 1.51.5 dB dB (without (without the the audience) audience) andand 2.3 dB (with dressing dressing rooms rooms on on the the stage) stage) at atmid-frequencies mid-frequencies and and therefore,therefore, the the presence presence ofof thethe audienceaudience and and the the dr dressingessing rooms rooms on on the the stag stagee cause cause small small changes changes in in termsterms of of music music perception. perception. The The parameter parameter C80 C80 shows shows that that the theatrethe theatre dated dated 1784 had1784 a had better a desirablebetter conditiondesirable for condition musical for performances. musical performances. The clarity C50 in all configurations results about 0.2 dB at 1000 Hz, which corresponds to quite good conditions for speech listening. The analysis then considered the sound strength (G), and the results show that the dressing rooms on the stage have no effect over the sound strength values in Scenario 1. Conversely, the presence of the audience in the hall significantly changes the results of the sound strength. Appl. Sci. 2020, 10, 8817 9 of 15 Appl. Sci. 2020, 10, x FOR PEER REVIEW 10 of 16

(a) (b)

FigureFigure 10. 10. AveragedAveraged values values of of the the simu simulatedlated acoustic acoustic parameters parameters ( (aa)) Ts, Ts, ( (bb)) C80, C80, ( (cc)) C50, C50, and and ( (dd)) G G for for thethe theatre theatre in in Scenario Scenario 1 1 (empty (empty theatre), theatre), Scenario Scenario 2 2 (with (with the the audi audience),ence), and and Scenario Scenario 3 3 (3D (3D model model reconstructedreconstructed according according to to the the plan plan dated dated 1784 1784 in in unoccupied unoccupied condition). condition).

FigureThe clarity 11 reports C50 in the all maps configurations of the T30, results C80, aboutand STI 0.2 in dB Scenario at 1000 Hz,1 (unoccupied which corresponds condition). to quiteThe mapsgood give conditions the following for speech indications: listening, the as foundreverberation in other time theatres is around [31]. The 1.55 analysis s in the then Royal considered box in front the ofsound the stage strength and seems (G), and that, the in results this area, show the that T30 the remains dressing almost rooms uniform on the as stage if the have sound no ewasffect perfectly over the diffused.sound strength The reverberation values in Scenario time values 1. Conversely, vary from the arou presencend 1.59 of s in the the audience stalls near in the the hall Prince’s significantly box to aroundchanges 1.68 the s results near the of thestage. sound strength. Figure 11 reports the maps of the T30, C80, and STI in Scenario 1 (unoccupied condition). The maps give the following indications: the reverberation time is around 1.55 s in the Royal box in front of the stage and seems that, in this area, the T30 remains almost uniform as if the sound was perfectly diffused. The reverberation time values vary from around 1.59 s in the stalls near the Prince’s box to around 1.68 s near the stage. Appl. Sci. 2020, 10, 8817 10 of 15 Appl. Sci. 2020, 10, x FOR PEER REVIEW 11 of 16

(a) (b)

(c)

FigureFigure 11.11. Color maps at 1 kHzkHz ofof thethe T30T30 ((aa),), C80C80 ((bb),), andand SpeechSpeech TransmissionTransmission IndexIndex (STI)(STI) ((cc)) inin unoccupiedunoccupied conditioncondition andand withwith asymmetricalasymmetrical positionspositions ofof thethe soundsound sourcessources AA andand BB onon thethe stage.stage.

AtAt thethe frequencyfrequency of of 1 1 kHz, kHz, the the parameter parameter C80 C80 results results around around 1.65 1.65 dB dB in thein the Royal Royal box, box, confirming confirming the uniformitythe uniformity of the ofperception the perception in all in the all positions the positi reservedons reserved for the for prince. the prince. However, However, the situation the situation in the stallsin the and stalls galleries and galleries differs differs significantly, significantly, in fact, in it fact, is interesting it is interesting to notice to notice that the that positions the positions in the in right the right side of audience area and the left galley have clarity values around 0 dB, whereas in the other parts of the hall the values are above 1.6 dB. Appl. Sci. 2020, 10, 8817 11 of 15

Appl.side Sci. of audience2020, 10, x FOR area PEER and REVIEW the left galley have clarity values around 0 dB, whereas in the other parts12 of of16 the hall the values are above 1.6 dB. Finally, inin order order to assessto assess speech speech intelligibility, intelligibi thelity, Speech the TransmissionSpeech Transmission Index (STI) Index was considered.(STI) was Theconsidered. parameter The results parameter’s are in results the good are range in the (the good values range span (the fromvalues 0.6 span to 0.7). from Anyway, 0.6 to 0.7). in Anyway, the stalls inand the galleries, stalls and focalization galleries, focalization phenomenon phenomenon seems to be seems forming to be but forming it is due but toit is the due diff toerent the different position positionof the sound of the sources sound Asources and B A on and the B stage. on the In stage. fact, theIn fact, diff erentthe different placement placement of sound of sourcessound sources results resultsin a nonsymmetric in a nonsymmetric distribution distribution of some acousticof some parameters,acoustic parameters, and this behavior and this is behavior more marked is more for markedclarity and for STIclarity values, and STI while values, the prince’s while the box prince’s has an box excellent has an sound excellent diffusion sound and diffusion the values and the are wellvalues distributed. are well distributed. The binauralbinaural room room impulse impulse response response was obtainedwas obtained to study to thestudy phenomenon the phenomenon of spatial impressionof spatial impressionin the theatre. in the Binaural theatre. room Binaural impulse room responses impulse (BRIRs) responses are calculated(BRIRs) are using calculated the directivity using the of directivityomnidirectional of omnidirectional decahedron and decahedron head-related and transfer head function-related (HRTF) transfer of virtualfunction receivers, (HRTF) according of virtual to receivers,the state-of-the-art according of to the the room state-of-the-art simulations [32of]. the The room simulations simulations of the [31] binaural. The IRssimulations were performed of the binauralfor five relevant IRs were receiver performed positions for five in therelevant main rece halliver and positions with the twoin the sound main sources hall and A with and Bthe on two the soundstage with sources theatre A and in theB on empty the stage configuration. with theatre in the empty configuration. In Figure 12,12, the result of the early interaural cross-correlation coefficient coefficient (IACC) (IACC) is is presented. presented. In this plotted graph, it can be noted that IACCIACC presents quite high values at low and medium frequencies, and this provides aa fairfair immersiveimmersive listeninglistening experienceexperience toto people.people.

Figure 12. AveragedAveraged values of the interaural cross-corre cross-correlationlation coefficient coeﬃcient (IACC) simulated in five ﬁve relevant receiver positions in the hallhall withoutwithout audience.audience.

Figure 13 reports a comparison between the result resultss of acoustic simulations with the audience, averaged for each sound source over three groupsgroups ofof receivers:receivers: stalls, Prince’s box, and galleries (Figure 1414).). These simulations aim to understand if the geometry of the Eszterháza Opera House favoredFigure the 13listening reports of the performances graphs of the in most the relevantPrince’s acousticbox. parameters here considered. For sake of simplicity, the analysis of the Just Noticeable Diﬀerence (JND) is reported only for the stalls, where the majority of the receivers are located. The comparison shows that for EDT and T30, diﬀerences fall within the limit of the JND range (5%) for the receivers in the galleries, whereas the simulated results in the Prince’s box are slightly lower than those simulated in the galleries and outside the JND range of the stalls. These results indicate that the reverberation is uniformly perceived in the stalls and gallery, whereas the Royal box is slightly less reverberant. This enhancement in reverberation brings greater results in terms of musical clarity and speech listening compared to the results in other positions so the prince could appreciate the balance between the voice and the orchestra. The C50 and C80 graphs show that the variability of the parameters is included in the JND range (1 dB).

(a) (b) Appl. Sci. 2020, 10, x FOR PEER REVIEW 12 of 16

Finally, in order to assess speech intelligibility, the Speech Transmission Index (STI) was considered. The parameter’s results are in the good range (the values span from 0.6 to 0.7). Anyway, in the stalls and galleries, focalization phenomenon seems to be forming but it is due to the different position of the sound sources A and B on the stage. In fact, the different placement of sound sources results in a nonsymmetric distribution of some acoustic parameters, and this behavior is more marked for clarity and STI values, while the prince’s box has an excellent sound diffusion and the values are well distributed. The binaural room impulse response was obtained to study the phenomenon of spatial impression in the theatre. Binaural room impulse responses (BRIRs) are calculated using the directivity of omnidirectional decahedron and head-related transfer function (HRTF) of virtual receivers, according to the state-of-the-art of the room simulations [31]. The simulations of the binaural IRs were performed for five relevant receiver positions in the main hall and with the two sound sources A and B on the stage with theatre in the empty configuration. In Figure 12, the result of the early interaural cross-correlation coefficient (IACC) is presented. In this plotted graph, it can be noted that IACC presents quite high values at low and medium frequencies, and this provides a fair immersive listening experience to people.

Figure 12. Averaged values of the interaural cross-correlation coefficient (IACC) simulated in five relevant receiver positions in the hall without audience.

Figure 13 reports a comparison between the results of acoustic simulations with the audience, averaged for each sound source over three groups of receivers: stalls, Prince’s box, and galleries (Figure 14). These simulations aim to understand if the geometry of the Eszterháza Opera House Appl. Sci. 2020, 10, 8817 12 of 15 favored the listening of performances in the Prince’s box.

Appl. Sci. 2020, 10, x FOR PEER REVIEW 13 of 16 Appl. Sci. 2020, 10, x FOR PEER REVIEW 13 of 16 (a) (b)

(c) (d) (c) (d) Figure 13. Simulated acoustic parameters ((a) EDT, (b) T30, (c) C50, and (d) C80) for the theatre with Figure 13. Simulated acoustic parameters ((a) EDT, (b) T30, (c) C50, and (d) C80) for the theatre with the Figurethe audience 13. Simulated in the main acoustic hall. parameters The values (( area) EDT, subdivided (b) T30, into (c) C50,three and groups (d) C80) (stalls, for Prince’sthe theatre box, with and audience in the main hall. The values are subdivided into three groups (stalls, Prince’s box, and gallery) thegallery) audience and inaveraged the main over hall. the The corresponding values are subdivided receivers. intoThe threeerror grbarsoups (Just (stalls, Noticeable Prince’s Difference, box, and and averaged over the corresponding receivers. The error bars (Just Noticeable Diﬀerence, JND) are gallery)JND) are and reported averaged for receiversover the correspondingin the stalls. receivers. The error bars (Just Noticeable Difference, JND)reported are reported for receivers for receivers in the stalls. in the stalls.

Figure 14. Figure 14. PlanPlan of of the the theatre theatre with with the the three three groups groups of re ofceivers: receivers: stalls stalls in yellow, in yellow, gallery gallery in blue, inblue, and and Prince’s box in red. FigurePrince’s 14. box Plan in ofred. the theatre with the three groups of receivers: stalls in yellow, gallery in blue, and Prince’s box in red. Moreover, the study of the separate results for the two sound sources A and B on the stage is Figure 13 reports the graphs of the most relevant acoustic parameters here considered. For sake reported in Figure 15. of simplicity,Figure 13 thereports analysis the graphsof the Just of the Noticeable most relevant Difference acoustic (JND) parameters is reported here only considered. for the stalls, For where sake ofthe simplicity, majority ofthe the analysis receivers of the are Just located. Noticeable The comp Differencearison shows (JND) thatis reported for EDT only and for T30, the differences stalls, where fall thewithin majority the limit of the of receivers the JND rangeare located. (5%) for The the comp receivarisoners in shows the galleries, that for whereasEDT and the T30, simulated differences results fall withinin the Prince’sthe limit box of the are JND slightly range lower (5%) than for the those receiv simulateders in the in galleries, the galleries whereas and outside the simulated the JND results range inof the the Prince’s stalls. box are slightly lower than those simulated in the galleries and outside the JND range of theThese stalls. results indicate that the reverberation is uniformly perceived in the stalls and gallery, whereasThese the results Royal indicate box is slightly that the less reverberation reverberant. isThis uniformly enhancement perceived in reverberation in the stalls brings and gallery, greater whereasresults in the terms Royal of boxmusical is slightly clarity less and reverberant. speech listen Thising enhancementcompared to thein reverberation results in other brings positions greater so resultsthe prince in terms could of appreciate musical clarity the balance and speech between listen theing voice compared and the toorchestra. the results The in C50 other and positions C80 graphs so theshow prince that could the variability appreciate of the the balance paramete betweenrs is included the voice in andthe JNDthe orchestra. range (1 dB).The C50 and C80 graphs show Moreover,that the variability the study of of the the paramete separaters resultsis included for the in thetwo JND sound range sources (1 dB). A and B on the stage is reportedMoreover, in Figure the 15.study of the separate results for the two sound sources A and B on the stage is reported in Figure 15. Appl.Appl. Sci. Sci.2020 2020,,10 10,, 8817 x FOR PEER REVIEW 1413 of of 16 15

(a) (b)

FigureFigure 15.15. ComparisonComparison of the average acoustic parameters parameters (( ((aa) )EDT, EDT, ( (bb)T30,)T30, (c (c) )C50, C50, and and (d (d) )C80) C80) simulatedsimulated with with receiversreceivers andand audienceaudience in the Prince’s box and the the two two sound sound sources sources A A and and B B on on the the stage.stage. TheThe errorerror barsbars (Just(Just Noticeable Difference Diﬀerence,, JND) JND) are are reported reported for for EDT EDT and and T30 T30 (5%) (5%) and and for for clarityclarity (1 (1dB). dB).

TheThe acousticacoustic parametersparameters werewere calculated only fo forr the the receivers receivers in in the the Royal Royal box box and and with with the the presencepresence of of the the audience. audience. ChangesChanges in reverberation ar aree very small, small, especially especially for for the the early early decay decay time time parameter,parameter, where where the the di differencesfferences between between the the two two sound sound sources sources fall fall within within the limitthe limit of the of JND the rangeJND (5%)range and (5%) the and early the reflections early reflections are slightly are perceived.slightly perceived. Moreover, Moreover, the T30 graph the T30 shows graph that shows the variability that the ofvariability the parameter of the is parameter included inis included the JND rangein the (5%)JND andrange there (5%) isn’t and a there relevant isn’t di aff relevanterence between difference the perceptionbetween the of theperception late reflections of the late produced reflections by the produced sound source by the A sound and by source the sound A and source by the B. sound sourceConversely, B. the position of the source on the stage influences much more the speech and music perceptionConversely, in the Prince the position box. Especially, of the source the C50on the graph stage shows influences that the much values more with the thespeech sound and source music in Aperception and B fall in within the Prince the limit box. of Especially, the JND range the C50 (5%) graph and speechshows listeningthat the values with the with sound the sound source source in A is betterin A and than B positionfall within B. Whilethe limit the of music the JND listening range (5%) in the and Royal speech box listening does not with seem the to sound be influenced source in by theA is position better than of the position sound B. source. While the music listening in the Royal box does not seem to be influenced by the position of the sound source. 5. Conclusions 5. Conclusions This paper has described the acoustic behavior of Eszterháza Opera House, a private theatre built accordingThis paper to has the described Hungarian the Prince acoustic Nikolaus behavior Esterh of Eszterházaázy’s wish. Opera The resultsHouse, obtaineda private fromtheatre the elaborationbuilt according of the to virtualthe Hungarian model showedPrince Nikolaus that the quiteEsterházy’s large volumewish. The of results the theatre obtained together from withthe theelaboration reflective of finishing the virtual materials model showed used in that its the interior quite makelarge volume the Opera of the House theatre a reverberanttogether with space. the Thereflective reverberation finishing time materials value ofused the in theatre its interior is acoustically make the favorableOpera House both a for reverberant the music space. and for The the wordreverberation transmission, time andvalue it of was the suitable, theatre is however, acoustic forally higher favorable ranks both who for attended the music chamber and for musicthe word and operastransmission, of the celebrated and it was suitable, composer however, Joseph Haydn.for higher Furthermore, ranks who attended the numerical chamber simulation music and analysisoperas showsof the thatcelebrated the audience composer may Joseph have hadHaydn. a minor Furthe influencermore, the on thenumerical acoustics simu oflation the theatre analysis due shows to the that the audience may have had a minor influence on the acoustics of the theatre due to the great Appl. Sci. 2020, 10, 8817 14 of 15 great volume of the Opera House and the seating number being limited to 200 at minimum capacity during daily performances and to 400 at maximum capacity during Court feasts. Another model of the theatre was simulated, including two dressing rooms at the back of the stage without the presence of the audience. The results show that the dressing rooms influence reverberation time, increasing sound clarity and the speech intelligibility, and enhancing the balance between the voice and orchestra, but they have no effect over the sound strength. Conversely, the presence of the audience in the hall significantly changes the results of the sound strength. The results confirm that the geometry and the shape of Eszterháza opera house favored the listening of the Hungarian Prince Nikolaus, decreasing the reverberation and improving the musical clarity and quality of speech listening in the Royal box. Indeed, the results indicate that the reverberation is higher in the stalls and gallery than in the Royal box. Finally, it is possible to state that the reproductions of musical instruments and singing voices are uniformly perceived in the different locations of the hall, and the positions of the sound source on the stage played a major effect on the speech intelligibility.

Author Contributions: Conceptualization, L.T.; methodology, F.M.; supervision, L.T.; funding acquisition, L.T.; data curation, F.M.; writing original draft preparation, M.D.; visualization, M.D. All authors have read and agreed to the published version of the manuscript. Funding: This work was carried on within the project n.201594LT3F, funded by PRIN (Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale) of the Italian Ministry of Education, University and Research and the project “SIPARIO-Il Suono: arte Intangibile delle Performing Arts–Ricerca su teatri italiani per l’Opera POR-FESR 2014-20”, n. PG/2018/632038, funded by the Regione Emilia Romagna under EU Commission. Acknowledgments: The authors wish to thank Giorgio Guidotti for his precious help during the development of the numerical model. Moreover, the authors are grateful to Giacomo Bilancioni, Carlo Bertuccioli, and Alessio Miecchi who collaborated during the simulating calculations for the theatre, and to János Malina for the material that he provided for the history of the theatre. Conflicts of Interest: The authors declare no conflict of interest.

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