DYNAMIC VARAITIONS OF DIRECT AND REFLECTED SOUND PRESSURE LEVELS USING BEAMFORMING (original) (raw)

Predicting the Acoustics of Ancient Open-Air Theatres: The Importance of Calculation Methods and Geometrical Details

For more than a decade now, computer simulations of sound fields in rooms have been widely adopted in research and for consulting purposes. Most computer simulations are either based on geometrical room acoustics or statistical methods, hereby neglecting diffraction and interference effects. The calculation algorithms in this type of simulations often combine the image-source method and the ray-tracing technique. In this paper, the acoustics of an open-air roman theatre are investigated. This is a special case which sets up a challenge to these prediction methods. The absence of a roof and therefore of a reverberant field, demands high accuracy in predicting the early reflections. The energy dissipates quickly in this type of enclosures and there is little masking effect of the reverberation. The inverse cone shape of these theatres also puts serious limitations to the image-source method, where great areas are in the shadow zone of the mirroring surface. Another aspect that has bee...

Virtual Acoustics of the Roman Theatre of Italica

2019

Classic outdoor theatres have special significance in the universal, cultural and architectural heritage. These scenic environments have undergone acoustic research in ERATO European project with basic purposes of recreation of associated intangible heritage and for their adaptation to contemporary cultural performances. In this work, the Roman theatre of the archaeological site of Italica (Seville) is studied by means of acoustic simulation, which responds to the classical scheme: cavea, orchestra, scenae, four-sided portico, and a capacity for 3,000 spectators. Throughout this paper, the creation process, adjustment, and validation of the 3D model of the theatre for simulating its sound field is analysed, which is based on the experimental measurement of reverberation time. The initial model, once validated, is modified to assess the acoustic impact of various proposed interventions.

The Accuracy of Predicted Acoustical Parameters in Ancient Open-Air Theatres: A Case Study in Syracusae

Applied Sciences

Nowadays, ancient open-air theatres are often re-adapted as performance spaces for the additional historical value they can offer to the spectators’ experience. Therefore, there has been an increasing interest in the modelling and simulation of the acoustics of such spaces. These open-air performance facilities pose several methodological challenges to researchers and practitioners when it comes to precisely measure and predict acoustical parameters. Therefore this work investigates the accuracy of predicted acoustical parameters, that is, the Reverberation Time (T20), Clarity (C80) and Sound Strength (G), taking the ancient Syracusae open-air theatre in Italy as a case study. These parameters were derived from both measured and simulated Impulse Responses (IR). The accuracy of the acoustic parameters predicted with two different types of acoustic software, due to the input variability of the absorption and scattering coefficients, was assessed. All simulated and measured parameters...

Architectural Acoustics: Paper 5aAA4 Virtual acoustic reconstruction of the Roman amphitheater of Avella, Italy

acoustical society of America, 2023

In ancient Rome, gladiator fights were very popular. The places where these shows took place were called amphitheaters, due to the particular shape of the elliptical building. Amphitheaters were constructed in every city. This paper describes the virtual acoustic reconstruction of the amphitheater of Avella, located near Naples, Italy. The amphitheater, discovered several decades ago and partially reconstructed, is now used for musical performances during the summer season. Acoustic measurements were carried out and the main acoustic parameters were determined according to the standard ISO 3382. Based on the dimensions and geometries of similar architectures of other amphitheaters, a virtual reconstruction of the original shape was performed. The virtual model was developed using Ramsete architectural acoustics software to obtain the acoustic characteristics of the amphitheater as it was in the Roman period. In particular, the spatial distribution of the acoustic properties on the cavea where the spectators sat is described and discussed.

Acoustic measurements of the Roman theatre of Pompei by mapping the sound reflections

2021 Immersive and 3D Audio: from Architecture to Automotive (I3DA), 2021

The city of Pompei has been always subject to archaeological works during the last decades. However, the theatre that has been discovered in the urban environment has one of the best preserved cavea, although it lacks most of the scaenae frons. This paper deals with the acoustic measurements undertaken to study the behavior of this important monument through the main acoustic parameter outlined by ISO 3382-1, and to detect the direction of the early and late reflections characterizing the reverberation. This latest approach enabled the possibility to investigate the sound propagation thought the space with the employment of a multichannel spherical array microphone. The recorded impulse response (IR) has been analyzed in a such a way to create an overlay video, given by the overlapping of the 360° image taken at the receiver position with the contour level of the sound decay after the impulse.

Acoustical measurements in ancient Greek and Roman theatres

Proceedings of FORUM ACUSTICUM SEVILLA, 2002

Acoustical measurements were conducted in two ancient theatres-one Greek and one Roman-the origin of modern opera houses and drama theatres. The Delphi theatre (Greece) does not have a stage building, while the Taormina theatre (Italy) has a partially remaining stage building behind the orchestra. The effect of the stage building on the sound field was determined in terms of the temporal and spatial factors of the sound field. It was found that the stage building affects and the magnitude of the interaural cross-correlation function (IACC). In addition to the reflection from the orchestra floor and the stage tower, scattered and reverberant sound from the audience area were observed.

COMPUTER SIMULATION OF THE EFFECT OF THE AUDIENCE ON THE ACOUSTICS OF THE ROMAN THEATRE OF BENEVENTUM (ITALY)

The acoustics of the Ancient Theatre of Beneventum has been object of attention by the authors since five years ago when measurements were carried out in the aim of its characterization in the present state. This theatre was built by Emperor Hadrian in the 1st century A.D. Later, historical events as barbarian invasions, earthquakes and floods determined its abandonment. A large part of the materials of the construction was used to build defensive walls in the Lombard period and for the embellishment of churches and palaces. During the course of subsequent centuries the theatre became the settlement of humble dwellings. At the start of the 20th century the crumbling houses were demolished to start the reconstruction of the theatre which was completed, as it appears in the present state, in 1950. This paper reports a computer simulation of the acoustics of the Roman Theatre performed by Odeon software. Calculated results are compared with those stemmed from the previous measurements carried out by the authors in the unoccupied theatre. Furthermore, a simulation of the effects of audience occupation on the acoustics is presented.

Virtual models for the prediction of acoustic fields of Manuel de Falla Auditorium in Granada, Spain

Applied Acoustics, 2012

This paper presents the results of the acoustic simulation of the Manuel de Falla Auditorium (MFA), Granada, Spain, carried out in CATT-Acoustic and CATT-TUCT. The 3D geometrical acoustic model created for this purpose is tuned by adjusting the absorption and scattering coefficients of the convex reflector ceiling of the auditorium through an iterative process aimed at rendering differences between simulated and measured values for reverberation time in each octave frequency band lower than 5%. The model is validated by comparing simulated and measured figures for the most significant monaural and binaural room acoustic parameters assessed at multiple locations both on the stage and within the audience areas, then by performing both spectral and spatial analyses of their behaviour, and ultimately studying dissimilarities between the two sets of data in terms of just noticeable difference (JND). The influence of the degree of detail of the geometric model on the outcome is also considered by incorporating the 44 iconic lamps specifically designed for this enclosure, into the model. Likewise, the acoustic effect of an already executed seating replacement in the performance space is analyzed in relation to the degree of occupancy of the room. The simulated results confirm the appropriateness of the choice of the new seating for the refurbishment of the concert hall.