Presentations in Panhellenic Conferences

This paper aims to examine the acoustical performance of drama theatres of modernity in postwar Hellas, in relation to their architecture. Acoustic measurements were carried out in seven theatres. Two theatre types are observed in this period, namely the type “less is more” and “detached” theatres. The first theatre type is usually hosted in the basement of multistory modern buildings. the other theatre type occupies an entire building in itself. It is demonstrated that the human scale which is adopted by the theatre type “less is more” works synergistically with good acoustics. by contrast the other theatre type needs additional building elements to achieve satisfactory sound performance. The present results illustrate the implications of architectural design on the acoustical performance of the theatres and demonstrate, by and large, the acoustical merits of the test auditoria.

Since the second half of the 20th century, a particular acoustic condition has been recognized, known as the Lombard effect, which is related to the effort of communication among people coexisting in the same space. Under this condition, speakers attempt to overcome background noise—partly consisting of simultaneous conversations—by continuously increasing their vocal intensity, thereby reinforcing the very “obstacle” they are trying to overcome. As a result of the Lombard effect, communication difficulties arise among participants and the acoustic comfort of the space is significantly reduced, leading to pronounced signs of fatigue and discomfort, especially among those working in such environments. Although in recent years scientific interest in this phenomenon has steadily increased, it still remains one of the contemporary issues in acoustics requiring further investigation. It is directly linked to the mechanisms of speech processing and comprehension in demanding environments (see also the cocktail party effect). In order to achieve desirable conditions of acoustic comfort in gathering spaces (e.g., restaurants, bars, foyers, waiting rooms, etc.), beyond meeting standard requirements (e.g., sound insulation), design principles must be adopted that limit the Lombard effect. The present paper consists of a literature review of the phenomenon, an overview of the calculation methods that have been proposed over time to assess the extent of the problem, as well as recent examples of applied acoustic solutions for its mitigation.

The students’ playground is undoubtedly a significant source of noise in the urban environment. Given the increasing population density in urban centers, many noise-sensitive buildings—such as residences, hospitals, and similar facilities—may be located near schools and are thus directly exposed to this type of urban noise pollution. Systematic monitoring of this noise can provide valuable data, enabling engineers to design effective noise protection measures for buildings adjacent to schools. Notably, even classrooms within the same school may be affected by such noise, particularly when there is a mismatch between teaching hours and recess periods.

This work aims to review related studies on the subject in the international literature. Special attention is given to the few studies addressing schools in Greece. The noise under investigation may be influenced by the students’ culture and, consequently, by the country where the studies are conducted. Therefore, referencing Greek studies is particularly valuable for applications in the local context. Additionally, the sensitivity of the results is acknowledged with respect to factors such as the education level and the number of students on recess. Interestingly, findings from studies in schools in Athens indicate that urban noise on central streets (e.g., Stournari Street) is generally lower than playground noise. Finally, this literature review attempts a comparison and evaluation of the findings across different studies, highlighting issues that remain open for further investigation.

Acoustic measurements in the auditorium, confirmed excessive Reverberation Time. Still it was important to maintain the initial character of the auditorium, i.e. to preserve the relatively large volume and initial shape of the space. The acoustical design consists in the introduction of sound absorptive treatment so as to reduce initial reverberation time and eliminate echoes (associated with the large auditorium). Sound amplification is also strongly recommended. Prediction of acoustic parameters as well as measurements in virtual space with the aid of software, fell within expected values. Coherence between acoustical design and the architecture of the auditorium, confirm that technology can be a source of inspiration for architecture.

Acoustic measurements in three historic drama theatres confirmed by and large their satisfactory acoustics. Contribution to acoustics was also confirmed, of architectural features, such as relatively small source-receiver distances, rich neoclassical decoration, coffered ceilings, etc. Despite basic differences in architectural features between neoclassicism and early-20th-century architecture, these were found to satisfy just as well acoustical design requirements.

Four auditoria of the above type, in Athens, were used to illustrate typical acoustical faults. Despite merits of neoclassical auditoria, acoustic measurements confirmed their need for remedial acoustics. Limitations in the remedial acoustic design are acknowledged, which are associated with the historic character of the auditoria. It is demonstrated that it is possible to cope with some of these limitations, thanks to versatile modern acoustic materials. Electroacoustics is also considered necessary.

The ancient theater of Epidaurus is regarded as the finest ancient greek theater in terms of acoustics and architectural design, being the most critically-acclaimed monument of its kind. Since 1954, the ancient theater has been hosting the annual “Epidauria” festival, one of the most important theater events in the world that include performances of ancient drama, attracting thousands of visitors and theater aficionados, who wish to enjoy the outstanding acoustics of the theater. Over the last decade, the use of microphones and electroacoustic amplification and reproduction systems has been established for the drama performances at the ancient theater. This is a rather controversial innovation, both in terms of aesthetics and acoustics, since the acclaimed physical sound propagation is questioned.In this paper the need for amplification will be discussed, as well as the ways the integration of modern systems have been affecting the perception of acoustics, both of actors and spectators of drama performances. In that respect, experimental data regarding the subjective evaluation of spectators, actors and other professionals of performing arts are presented and further discussed. The aim of this paper is to answer whether the physical acoustical properties of the ancient theater can be enhanced by modern technology or, on the contrary, the latter will result in the degradation of the overall acoustical experience.

Classical methods for predicting the acoustic behavior of auditoria have often led in the past to extremely costly errors. Thanks to advanced technology, it is now possible to digitally simulate the acoustic identity of a space. This makes it feasible to experience the sound of a hall either before its construction or in existing venues prior to acoustic restoration. Furthermore, such simulation can serve as an educational tool and as a means of cultivating acoustic awareness for students, emerging musicians, architects, and contemporary users in general. The presentation includes an acoustic demonstration of the above technique using advanced software.

The earliest attempts to investigate the acoustics of orthodox churches in modern Greece are fairly recent and refer either to physical measurements or to subjective evaluation experiments of the acoustics during live liturgy. The present study is a review of the above research work. Relevant acoustic measurements from various studies of this kind demonstrate that the values of critical acoustic parameters are well beyond optimal values· interpretation of this is attempted in terms of architectural characteristics of the churches. Furthermore, it was experimentally confirmed that the use of loudspeakers in orthodox churches of modern Greece mars the quality of the authentic byzantine chant.

Physical acoustic measurements were carried out in Athens in four rock concert halls· the latter were of relatively small size. Comparison of present results with optimal values demonstrated that the present rock concert halls have good acoustics, mainly owing to their relatively small size. Furthermore, comparison with European rock auditoria of good acoustics confirmed that the present auditoria have good acoustics. Further research is necessary to identify subjectively significant physical room acoustic criteria.

This paper refers to the multipurpose auditorium "Lyssandros Kautantzoglou" of the School of Architecture, which is in the ‘Averof’ building of the Tech. Univ. Athens. The auditorium is over 100-years old, and acoustic problems are associated with the hall’s neoclassical character, even after a recent restoration. This study is part of a research work which aims to remedy the acoustics of the auditorium. The basic tool, used in this study for predicting as well as for simulating (auralising) the auditorium’s response after treatment, is the ΄Odeon room acoustics' software. ‘Odeon’ is tested in this study with respect to its capabilities as simulator; this is implemented through comparisons of acoustic measurements before treatment, which were carried out on the one hand in the field, and on the other hand in the virtual space.

Research on the acoustics of jazz venues has been conducted for only a few years. During this time, the ways in which acoustic perception occurs have been explored, both by the audience and by performing musicians on stage. The results obtained so far, when combined with physical acoustic measurements, can provide insights for the design of such spaces. Similarly, studies in the contemporary literature on rock music acoustics highlight the suitability of small venues, which can be adapted at low cost. Recommended values for reverberation time and its spectral distribution are also proposed, with particular emphasis on reducing reverberation in the low-frequency range (63 Hz). Additionally, aspects of the audience’s acoustic perception in such spaces are examined. Finally, recommendations for further research are provided, which may contribute to the formulation of design principles and techniques for jazz and rock music venues.

Suitability of relatively small auditoria for rock music is demonstrated in relevant modern literature. Desired values for reverberation time as well as for the spectral balance of the latter are proposed with emphasis on the need for short reverberation time at the low frequency end of the spectrum from 63Hz oct. band. Furthermore, there are illuminated some of the ways a fairly large cross section of rock concert goers describe their acoustic experience of listening to live music. Further research is necessary in order to suggest acoustic principles and techniques for the design of rock auditoria.

Jazz music commenced from the United States in the early 20th century and since then, especially the last decades, it has become famous and popular across the world. The places where concerts of this music genre are organised, are often conversions of other spaces and their design is often a result of intuition, thus they fail to meet the requirements of both the musicians and of the audience. We researched via an experiment, the subjective evaluation of such concert spaces, in order to contribute to the introduction of design principles for jazz music venues. Our experiments were completed during live jazz concerts and they were based on the use of semantic differential theory which mainly uses semantic rating scales. At a next stage, the data that was collected, were analysed by applying factor analysis to them and as a result, several common factors have been extracted that describe the relations between our data. Finally our results and conclusions offer a basis for the further scientific research that will aim at identifying the principles for the optimum design of jazz music venues.