1,720,986 research outputs found
Validation and application of three-dimensional auralisation during concert hall renovation
No full textDuring the renovation of auditoria and concert halls, the acoustic quality is normally evaluated from measurements of impulse responses. One possibility for evaluating the acoustic quality from the measurements (the simulations) consists of convolving anechoic music with the measured (or simulated) impulse responses. In this way, a psycho-acoustic test is achieved using a virtual sound field representation. The listening room ‘Arlecchino’ at the University of Bologna includes ambisonics (up to fifth order) and stereo-dipole playback for virtual reproduction of sound in rooms. In this article, the effectiveness of the listening room ‘Arlecchino’ is first analysed, comparing acoustic parameters obtained from binaural impulse responses measured in some opera houses (in Italy) and auditorium (in Japan) with those virtually measured after the virtual reconstruction obtained in the listening rooms. The similarity between real and virtual sound fields, has been evaluated by comparing different acoustic parameters calculated by real and virtual sound fields, in four halls in different configurations, by means of the stereo-dipole method. In the second part of the article, the listening room was used to analyse the variation in interaural cross-correlation measurements in rooms obtained considering different anechoic sound signals convolved with the binaural impulse responses, to quantify the variation of the interaural cross correlation with different motifs. For this purpose, two different musical instrument digital interface musical motifs, very different from each other for their music characteristics, have been considered. Moreover, for each musical motif, different sound characteristics (i.e. different musical instruments) were considered, to consider both the rhythmic and timbre aspect
The sound diffusion in Italian opera houses: some examples
No full textSoundfield diffuseness in rooms is considered a fundamental aspect of a high-quality room acoustics. Since early studies by Hodgson up to more recent studies of Shtrepi and Embrechts, it was shown that high levels of sound diffuseness could guarantee blending of music, as well as spatial sound perception by listeners, and this could enhance the global indoor acoustic quality. Conversely, Italian-style Opera houses represent an important architectural place, in which the special features of the rich decorations, and the specific characteristics of the volume, give a unique atmosphere, including a peculiar psycho-acoustics impression. However, some geometric properties of the opera houses could influence the global acoustic perception. The shape of the marmorino wall on the stalls, as well as the parallelism of the lateral walls in the boxes, often causes a lack of spaciousness and sometimes in the worst cases provokes focalization. This phenomenon leads to design special devices that could be inserted in the theatres, to avoid focalization, even if they are rarely accepted. This article deals with the design of some acoustic diffusing panels and their functioning in three different theatres, combining both acoustics needs with architectural constraints. The article starts analysing and commenting on the issues that resulted from the measurements conducted in an Italian opera house. In the following step, three examples of the design of diffusing panels are proposed. Finally, the results of diffusion and scattering coefficient of panels realized in the last theatre considered here are reported
Virtual acoustic reconstruction of the Miners’ Theatre in Idrija (Slovenia)
Full text linkThis study reports history and the original architectural design of the Miners’ Theatre in Idrija. This theatre is usually considered to be the oldest such building in Slovenia and in 2001 it was declared a cultural monument of national importance. The building shape was typical of numerous small stand-alone theatres throughout Central Europe in the 18th century. The original design was later changed several times until it has reached the actual aspect. To analyse the acoustic characteristics of the current room (often named “Film Theatre”), an acoustic survey was carried out and several acoustic parameters defined in the ISO 3382-1 standard, were calculated and analysed. To study the acoustic characteristics of the theatre in its original shape, a numerical model was realized and properly validated. The simulations of three different scenarios were performed and the results obtained from the simulation have been analysed and commented
Evaluation of different solar control strategies for a commercial building in moderate climate.
No full textWindows have an important role in buildings both for daylighting, thermal comfort, and energy consumption. The aim of the paper is to evaluate the influence of glazings in energy saving for non-residential buildings, by considering advanced solar control solutions such as spectrally selective glasses. A multifunctional building was investigated and a dynamic thermal model was implemented by means of EnergyPlus software. The energy demand was estimated in different climatic conditions both for heating and cooling, by considering three Italian cities (Perugia, Milan, and Palermo). In order to evaluate the influence of windows, different kind of glazings were selected: conventional double-glazing with low-e coating and solar control double glass windows. In particular, three commercial solutions from different manufacturers were chosen, considering the latest generation of technology. Optical measurements were carried out on the samples using a spectrophotometer working in the 300-2500 nm range, the visible and solar transmittance were calculated according to EN 410 Standard and the experimental data were used as inputs in the thermal model. Finally, also the effects of blind systems on the façades were evaluated and the results were compared to solar control glazings performance. Results showed that not only the thermal transmittance but also the solar transmittance of glazings has a large effect on thermal comfort and energy demand, depending on the climate conditions. The spectrally selective solar control glazings showed significant benefits, especially in summer, due to their combined low solar transmittance and low emissivity properties, without penalizing the natural light transmission
A psycho-acoustical experiment using a stereo dipole for spatial impression of music signals
No full textAcoustic performance of concert halls and opera houses is usually assessed by measuring the BIRs (Binaural Impulse Responses). Anechoic music convoluted with BIRs constitutes the virtual sound in the way it is played in the sound field, i.e. the room. From BIRs, the IACC (Inter-Aural Cross Correlation) can be computed. This parameter makes it possible to evaluate the spaciousness of the hall. However, the calculation of the IACC value is affected by the convolution technique used as well as the kind of musical motif. For example, in the same concert hall, the BIR provides three different IACC values in the case of three different motifs played in it. This study has conducted a psycho-acoustic experiment by using a virtual sound field representation produced by the stereo dipole technique in a listening room. In the experimental set-up there were two or four loudspeakers, corresponding to the single stereo-dipole or the dual stereo-dipole, respectively. By cancelling the cross-talk pathways (i.e. from left loudspeaker to right ear), the parallel sound presentation creates a 3D sound field for listeners sitting in the target point. The invert Kirkeby method was adopted to determine the inverse filters. Finally, the auralization technique with measured BIRs in theatres was utilized and the virtual sound field was generated in the Arlecchino listening room (Bologna, Italy), a low reverberation room equipped with an Ambisonic system. In the virtual sound field, the BIR was recorded again by the same dummy head used during the measurement in the theatres. The similarity between real and virtual sound fields was evaluated by comparing some acoustic parameters. The stereo-dipole technique demonstrates a good degree of accuracy of the sound field appearance. Moreover, the accuracy of the sound field appearance was analysed using two musical motifs and three musical instruments, comparing the values of the IACC calculated by echoic music with the virtual echoic music.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Thermal and Acoustic Properties of Aerogels: Preliminary Investigation of the Influence of Granule Size
No full textThe influence of granules size in silica aerogels is experimentally investigated in terms of thermal and acoustic performance characteristics. The transmission loss (TL) is measured at normal incidence in a traditional Impedance tube, whereas the thermal conductivity (λ) is evaluated using a Hot Plate apparatus, setting up an appropriate methodology, due to the nature of the sample.
The results reveal that the small granules (granules size in the 0.01-1.2 mm range), which have the highest density, have the best performance both in terms of thermal and acoustic properties. Depending on the granules size, λ varies in 19-22 mW/mK range at 10°C, whereas a TL equal to 13 dB at about 6400 Hz for 20 mm thickness is obtained for small granules
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The acoustic simulation of performing area in the auditorium: Some examples in Italy
No full textThe design of auditoria and opera houses requires particular care for the stage area, where several different requirements should be achieved for the performers. Among these, the acoustic quality represents a fundamental aspect, and it differs from the listeners' perspective. Moreover, the performing area in concert halls is often an important area for non-acoustic reasons, since lighting, thermal plants, etc. are often placed in this special zone, and should be properly designed in order to guarantee a high level of global comfort. This paper presents some examples of how to design exhibition zones in opera houses and auditoriums that show both acoustic and technical improvements, both in theory and in architecture.</p
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