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Ein objektives Kriterium zur Erfassung von Echostörungen bei Musik- und Sprachdarbietungen
Abstract
The cause of echo-disturbances during presentation of music and speech in rooms has been investigated in a synthetic sound field. Arising out of the echo analysis a new method is proposed for analysing impulse responses in rooms. In numerous additional tests the new method was verified by comparing subjective judgements on echo disturbances with the respective impulse response, in the synthetic sound field as well as in real rooms.Zusammenfassung Durch subjektive Tests in einem synthetischen Schallfeld wurde das Zustandekommen von Echostörungen bei Musik und Sprache untersucht. In Auswertung der Meßergebnisse wird ein neues Echoanalyseverfahren für die Anwendung beim raumakustischen Impulsschalltest vorgeschlagen. Das Echoanalyseverfahren wurde durch zusätzliche umfangreiche Tests im synthetischen Schallfeld sowie durch Auswertung von subjektiven Urteilen und Raumimpulsantworten in realen Zuhörerräumen überprüft und bestätigt.Sommaire On avait commencé par rechercher les manifestations d'une gêne due aux échos, au cours de la présentation de musique ou de parole dans une salle, au moyen de tests subjectifs en champ acoustique synthétique. L'examen des résultats a suggéré un nouveau procédé d'analyse des échos reposant sur l'étude de la réponse impulsionnelle de la salle et permettant de sélectionner les échos gênants. La validité de cette nouvelle méthode a été vérifiée par de nombreuses expériences, en champ réel comme en champ synthétique, avec comparaison entre des réponses impulsionnelles et des jugements subjectifs.
... As these parameters are closely linked together, alternatively to the lead-lag delay DT, some studies define the echo threshold as level difference DL between leading direct sound and lagging specular reflection, e.g. [20,21]. Thus, a stronger echo suppression is implied by a longer echo threshold delay or a higher echo threshold level. ...
... For all conditions the diffuse threshold level is below the corresponding specular threshold level. A Tukey HSD post hoc analysis of both reflections types shows conditions A (20,30) of the echo threshold and all conditions of the masked threshold to be significantly different (p 0.05) with effect sizes expressed as Cohen's d ! 0.9, i.e., large effects [28]. ...
... For a diffuse condition on the other hand, the decay of the reflection amplitude is flatter than the logarithmic function given in Equation (7). Accordingly, peaks of the reflection envelope exceed the masking pattern at DT M at a lower level, cf. Figure 9. Fitting parameters for specular and diffuse masked levels of conditions A (10,20,30) are calculated using Equation (7) and are c = 2.4 dB, = À12.6 dB, and dL = À7.8 dB (corresponding 95% confidence intervals: c = [À6.7, 11.5] dB; = [À15.7, ...
Studies on the precedence effect are typically conducted by presenting two identical sounds simulating direct sound and specular reflection. However, when a sound is reflected from irregular surface, it is redirect into many directions resulting in directional and temporal diffusion. This contribution introduces a simulation of Lambertian diffusing reflections. The perceptual influences of diffusion are studied in a listening experiment; echo thresholds and masked thresholds of specular and diffuse reflections are measured. Results show that diffusion makes the reflections more easily detectable than specular reflections of the same total energy. Indications are found that this mainly due to temporal diffusion, while the directional diffusion has little effect. Accordingly, the modeling of the echo thresholds is achieved by a temporal alignment of the experimental data based on the energy centroid of reflection responses. For the modeling of masked threshold the temporal masking pattern for forward masking is taken into account.
... However, in a constellation of sound source, receiver, and reflective wall, cf. Figure 2.2, these two parameters are closely linked because the distance traveled by the reflection determines not just the delay ∆T , but also the inverse-square law intensity difference ∆L of the reflection compared to the direct sound. The echo threshold is then defined as the intensity difference ∆L for a fixed delay ∆T [DK86,RHH00]. Thus, a stronger precedence effect, i.e., a stronger echo suppression, is implied by a longer echo threshold delay or a higher echo threshold level. ...
... Another echo threshold definition measures the delay for "a second sound heard at the vicinity of the lag speaker", e.g., [FCL91], yielding higher thresholds. Further increases of the echo threshold are obtained if the definition asks for a "reflection that is annoying", e.g., [DK86], or for a "reflection that is equally loud as the primary auditory event", e.g., [Haa72]. ...
... Linearly fitting experimental data examining speech yields slopes ranging from β ET = −0.20 dB/ms to −0.35 dB/ms [LB58,San76,RHH00]. Similarly for music, fitted slopes are content dependent and resemble those of speech [DK86]. Hence, the slope β ET depends on the non-stationariness of the signal and more transient signals yield steeper slopes β ET compared to smooth-onset signals. ...
The perception of sound in rooms is influenced by the room acoustics. Depending on geometrical properties and texture of the room, a direct sound is followed by multiple reflections. For standard surrounding audio reproduction systems, the influence of reflections on the perception is well studied. Recent developments allow more particular constellations and compact loudspeaker arrays with highly pronounced variable directivity patterns that excite wall reflections from a single point in the room to spatialize auditory events. However, their prediction in space mostly fails when standard localization models are used. This is because the underlying psychoacoustic principles are different from those known for standard spatialization systems. This doctoral thesis investigates perceptions elicited by the sound field of a directional sound source in a room. Starting from auditory events evoked by a few precisely controlled sound instances examined in the laboratory, the aim of this work is to understand what perceptions are formed by the interaction of direct sound and its reflections. This bottom-up approach allows the development of models of perception building upon the measurements from the different stages of experimental complexity.
... LF80 is an indication of the apparent source width (ASW). • Dietsch's echo criterion predicts if there is a certain peak in the impulse response that indicates an unwanted audible echo (Dietsch and Kraak, 1986;Kuttruff, 2017 ...
... Figure 8 shows a series of scatter plots of mean acoustic comfort rating as a function of the individual room acoustical parameters. Except for the echo criterion by Dietsch and Kraak (1986), the All significant cases are significant at the level of **p < 0.01. ...
... This is further quantified by the significant correlations between acoustic comfort and the individual parameters. Pearson's correlation coefficient, r, is reported in Table 2 for correlations between acoustic comfort ratings and the room acoustical parameters of Figure 8. Except for the echo criterion by Dietsch and Kraak (1986) in Experiment 3, all correlations were found to be significant. Note that, whereas, for Experiment 1, rather moderate correlations were observed, for Experiments 2 and 3, correlations were very weak. ...
Room acoustical parameters have frequently been used to evaluate or predict the acoustical performance in rooms. For housing complexes in urban areas with high population density, it is important to improve acoustic performance not solely indoors, but outdoors as well; for example on the balconies or in the yards. This paper investigates to what extent classic room acoustical parameters would be able to predict the perceived acoustic comfort in outdoor spaces (i.e., courtyards) of virtual housing complexes. Individual and combined effects of a series of independent variables (such as facade absorption, sound source, and observer position) on short-term acoustic comfort were investigated in three laboratory experiments. ODEON software was used for virtual inner yard simulation, whereby 2D spatialization was carried out for a playback over five loudspeakers. Moderate facade absorption was found to increase acoustic comfort. Relatively pleasant and relatively unpleasant sounds were associated with comfort and discomfort, respectively. Lower acoustic comfort ratings were observed at receiver positions with high sound pressure levels and/or strong flutter echoes. A further analysis of the results is carried out here with respect to the room acoustical parameters and their ability to predict the acoustic comfort ratings. Speech transmission index (STI), definition (D50), clarity of speech (C50) and music (C80), early decay time (EDT), and lateral energy fraction (LF80) were found to be significantly correlated with acoustic comfort. They were found to be significant predictors of acoustic comfort in a series of linear mixed-effect models. Furthermore, linear mixed-effect models were established with the A-weighted equivalent continuous sound level, LAeq, as a significant predictor of acoustic comfort.
... The center time, T S (ms), another indicator of sound clarity, was also used to detect strong delayed reflections or echoes, leveraging the fact that its formulation does not strictly differentiate between early and late reflections (Paini et al., 2011). In addition to T S , the presence of audible echoes for speech and/or music reproduction was objectively evaluated with the Dietsch and Kraak echo parameter (Dietsch and Kraak, 1986). Finally, the capacity of each site to increase the loudness of sounds produced in them was assessed via the strength parameter G (dB), which is referenced to the level emitted by the sound source at a distance of 10 m in the free field. ...
... Furthermore, the low T Sm values obtained at all sites (T Sm < 30 ms), which are not calculated using an established division between early and late reflections, expose not only a satisfactory degree of speech intelligibility (Fürjes and Nagy, 2020), but also the absence of any echoes or relevant delayed reflections. In addition to this initial cue on the lack of echoes, the Dietch & Kraak echo criterion for both speech and music (Dietsch and Kraak, 1986) was explored without obtaining any positive value. ...
Over the past two decades, scholars have proposed the existence of a strong relationship between sound, acoustics, and the production of San rock art in certain places. However, this intriguing hypothesis had never been tested through the systematic application of a rigorous method to a substantial sample of sites. In this paper, we present an unprecedented archaeoacoustic study conducted at 27 shelters with San paintings located in the Maloti-Drakensberg mountains (South Africa). The results obtained through the use of the impulse response (IR) method indicate that such a relationship should not be considered a pattern, but a circumstantial occurrence identified only in specific parts of the South African territory. Drawing on these data, we suggest that in our study area, the choice of sites to be painted may have been predominantly influenced by ontological beliefs concerning how the San perceived the shelters and the surrounding landscape.
... Whether a certain reflection or a group of reflections is subjectively perceived as an echo depends on several factors, including the time delay and level of the reflection as well as similar data on preceding reflections. To detect echoes in our material, we used the echo criterion (EK) proposed by Dietsch and Kraak (1986), differently weighted for speech (EKspeech) and music (EKmusic) performances. The echo strength values were calculated from the impulse responses using the EASERA (Electronic & Acoustic System Evaluation & Response Analysis) 1.2 software by AFMG. ...
... The artistic sound samples and our vocal and instrumental field recordings demonstrate how the strong discrete echoes at the unchanged rock art sites affect sonic performances. According to Dietsch and Kraak (1986), such echoes interfere with speech and music, annoying listeners, but this value judgement reflects the norms of our time. Since standard room acoustics has primarily focused on eliminating echoes, rather than investigating them, detailed information on their effects on performers, performations, or spatial environments is not readily available. ...
This article seeks to recapture the sensory experiences of prehistoric hunter-gatherers in the Finnish Lake District by examining the acoustics of their rock art sites. The sites consist of vertical cliffs rising directly from the lakes, with painted images of humans, boats, and animals, sometimes also drummers (5000-1500 calBC). The acoustic impulse response measurements performed at 37 sites indicate that the painted cliffs, in their original state, reflected sound more strongly and accurately than the nearby lakeshore rocks. The psychoacoustic criterion and the auralizations created through artistic improvisations indicate that the reflections generated discrete single-repeat echoes, which endowed sounds produced in front of the cliffs with their auditory mirror images. As these reflections appeared to emanate from invisible sources behind the paintings, the auditory and visual images overlapped merging into one multisensory experience. Although the sounds and music of prehistoric people are beyond our reach, the study shows that the physical environment actively participated in their activities, co-vibrating and creating reciprocal tangible encounters between the human and more-than-human worlds. For the history of sound and music, the study provides an example of how significant a role sound reflections could have in past societies.
... late reflections(Paini et al., 2011). In addition to T S , the presence of audible 243 echoes for speech and/or music reproduction was objectively evaluated with the Dietsch 244 echo parameter(Dietsch and Kraak, 1986). Finally, the capacity of each site to increase 245 the loudness of sounds produced in them was assessed via the strength parameter G (dB), 246 which is referenced to the level emitted by the sound source at a distance of 10 meters in 247 the free field. ...
... Furthermore, the low T Sm values obtained at all sites (T Sm < 30 ms), 326 which are not calculated using an established division between early and late reflections, 327 expose not only a satisfactory degree of speech intelligibility (Fürjes and Nagy, 2020), 328 but also the absence of any echoes or significant delayed reflections. In addition to this 329 initial cue on the lack of echoes, the Dietch & Kraak echo criterion for both speech and 330 music(Dietsch and Kraak, 1986) was explored without obtaining any positive value. ...
Over the past two decades, scholars have proposed the existence of a strong relationship between sound, acoustics, and the production of San rock art in certain places. However, this intriguing hypothesis had never been tested through the systematic application of a rigorous method to a significant sample of sites. In this paper, we present an unprecedented archaeoacoustic study conducted at 27 shelters with San paintings located in the Drakensberg mountains (South Africa). The results obtained through the use of the Impulse Response (IR) method indicate that such a relationship should not be considered a pattern, but a circumstantial occurrence identified only in specific parts of the South African territory. Drawing on these data, we suggest that in our study area, the choice of sites to be painted may have been predominantly influenced by ontological beliefs concerning how the San perceived the shelters and the surrounding landscape.
... The echo parameter was introduced by Dietsch and Kraak [21]. They derived two slightly different parameters, one for speech and another one for music. ...
... The risk of a disturbing echo is much higher than in a closed room. In order to identify possible echo problems, the echo parameter for speech by Dietsch and Kraak [21] is found to be very useful. ...
The acoustics of performance spaces are usually characterized by the reverberation time and a handful of other acoustical parameters defined in ISO 3382-1. However, these parameters have been derived with closed spaces in mind, and it is not obvious that the same parameters are meaningful in an open-air theatre. The lack of late reflections means that the decay curve is often far from a straight line, and the reverberation parameters turn out to be unreliable. Also, parameters that use the balance between early and late reflections are problematic when late reflections are more or less absent. It is necessary to rethink the need for acoustical parameters instead of sticking to the well-established parameters meant for concert halls. The most important acoustical features of a theatre are that speech is sufficiently loud and clear, which can be described by acoustical parameters for strength and clarity. In addition, it is important to avoid echoes, which are more likely to appear in an outdoor environment than in a room. Thus, there is a need for an objective echo parameter. Acoustical parameters that vary strongly with receiver position are not well suited for a global characterization of the acoustics of a space. For this purpose, a parameter for the acoustical efficiency is suggested; it is defined as ten times the logarithm of the total sound energy in the impulse response relative to the energy of the direct sound. The spatial average of this parameter can be used for comparison of the acoustics of different open-air theatres.
... Even so, the average T 20 of 0.9 seconds suggest that the shelter was a suitable place not only for speech transmission, but also for the production and appreciation of music (Harris 1991), especially when considering the lack of reverberation inherent to the open conditions of the other rock art sites in the study area. Moreover, no echoes can be discerned in any of the IR according to the Dietsch and Kraak (1986) echo criterion, given that the curve remains well below the brown line in Figure 7D. ...
... Reverberation parameters were estimated from double-slope decay curves. Figure 7. A) Impulse response measured in Cuevas de la Araña at the receiver position R02 when the source was located at S01; B) Schroeder integral (Schroeder 1965); C) echogram; and, D) echo speech function calculated according to Dietsch and Kraak echo criterion (Dietsch and Kraak 1986). study of Cuevas de la Araña. ...
Since the 1980s, research into aggregation sites has focused on the material dimension of the archaeological record and has thus led to an incomplete view of the prehistoric reality. Early communities chose sites for many reasons. In this article, we explore the possibility that something as immaterial in nature as the acoustics of the sites may have influenced the selective choices made by the prehistoric peoples who created and used rock art in these meeting places. Employing the Impulse Response (IR) methodology, we systematically analyze the acoustic properties of Cuevas de la Araña, an aggregation site in eastern Spain with Levantine rock art, and 16 satellite sites in its surroundings. The results indicate that the acoustics of La Araña could have been important for creating affective engagement through musical performances carried out during the production and use of rock art, as well as for the choice of the site as a meeting place for Levantine populations.
... One of the most important phenomena that can be observed in rooms with curved surfaces is focusing and echo [1]. The echo criterion suggested by Dietsch & Kraak [13] has been implemented in ODEON, since version 11, to help locating positions with echo problems. According to this criterion, echo values above 1 can cause annoyance due to echo to more than 50% of people and values above 1.5 can cause annoyance to more than 90%. ...
... The parameter was introduced to represent the energy arriving at the floor due to first order focused reflection from the main dome. Although the changes are generally lower than 1 JND for this parameter, some noticeable fluctuation occurs for discretisations lower than (M,N ) = (50, 13). After that, the error seems to stabilize. ...
A common characteristic of worship spaces in Eastern and Western Mediterranean cultures is the existence of large curved surfaces, usually in form of domes at the ceiling. Modeling of such spaces using geometrical acoustic algorithms typically requires discretisation of curved surfaces into planar elements. The degree of discretisation plays a crucial role in the quality of results, and simulation of several acoustic phenomena such as focusing. In this article an investigation of the size of discretized elements is performed using the ODEON Room Acoustics Software, version 14. For this investigation a model of the mosque "Selimiye" has been used. Impulse responses of this space were recorded in many positions as part of the CAHRISMA project (Conservation of Acoustical Heritage by the Revival and Identification of the Sinan's Mosques Acoustics) in 2000 - 2003. The model has a big central dome and several other surrounding curved surfaces. Measured room acoustic parameters are compared with simulated ones while varying the discretisation of curved surfaces and several simulation parameters for the best possible agreement. The advantages and disadvantages of very high discretisation are discussed, and the question whether there is an optimum degree of discretisation or not is addressed.
... One of the most important phenomena that can be observed in rooms with curved surfaces is focusing and echo [1]. The echo criterion suggested by Dietsch & Kraak [13] has been implemented in ODEON, since version 11, to help locating positions with echo problems. According to this criterion, echo values above 1 can cause annoyance due to echo to more than 50% of people and values above 1.5 can cause annoyance to more than 90%. ...
... The parameter was introduced to represent the energy arriving at the floor due to first order focused reflections from the main dome. Although the change is lower than 1 JND, some fluctuation occurs for discretisations lower than (M, N ) = (50, 13). After that, the error seems to stabilize. ...
A common characteristic of religious spaces in Eastern and Western Mediterranean cultures is the existence of large curved surfaces, usually in form of domes at the ceiling. Modeling of such spaces using geometrical acoustic algorithms typically requires discretisation of curved surfaces into planar elements. The degree of discretisation plays a crucial role in the quality of results, and simulation of several acoustic phenomena such as focusing. In this paper an investigation of the size of discretized elements is performed using the ODEON Room Acoustics Software, version 13. For this investigation a model of the mosque " Selimiye " has been used. Impulse responses of this space were recorded in many positions as part of the CAHRISMA project (Conservation of Acoustical Heritage by the Revival and Identification of the Sinan's Mosques Acoustics) in 2000-2003. The model has a big central dome and several other surrounding curved surfaces. Measured room acoustic parameters are compared with simulated ones while varying the discretisation of curved surfaces and several simulation parameters for the best possible agreement. The advantages and disadvantages of very high discretisation are discussed, and the question whether there is an optimum degree of discretisation or not is addressed.
... The rest of studies were focused on procedure to quantify the echo and its disturbance considering the relative amplitude and time delay e.g. Ref. [3][4][5][6]. ...
... Some objective criteria have been established for evaluating specular reflections being disturbing flutter echo or not. The one was proposed by Dietsch and Kraak [5]. They proposed an objective echo criterion for music and speech which is based on the ratio ...
An acoustic measurement has been conducted to assess acoustic performance of the Main Stadium of Gelora Bung Karno (GBK), Jakarta, as the largest football stadium in Indonesia. From measurement results, it was found that some acoustical defects are noticeable particularly related with echo or flutter echo and sound clarity. Considering the results, it is instructive to investigate further and found physical explanation to the acoustical defects from the elliptical shape and open space of football stadium. For this, the ray tracing simulation based is employed that is implemented using software CATT. The simulation results indicate that the roof area have contributed to the presence of specular reflected sound with delays in excess of 50 ms. This has caused the presence of a multiflutter echo (or discrete echo). Meanwhile, poor clarity (D50<50%) is mostly related with higher energy of late response although it is naturally beneficial to hide the perceptibility of echo by listeners. Hence, an area of GBK with poor clarity is not necessarily having echo disturbances and vice versa. Considering the results, a necessary acoustic treatment can be focused to control those reflected sound energy by refining the acoustic properties of roof area. However, a great care is required to control early and late response in order to have a good clarity as well as suppress the echoes for the case of a large space.
... Since echo can be an issue in open-air theaters, the echo strength by Dietsch and Kraak (1986) is found to be relevant and useful. If the value exceeds unity, there is a high probability of an annoying echo. ...
In ancient Greece, the 4th century B.C.E. was a time of rapid development in arts, culture, science, politics, and theater architecture. The first part of this article describes the origin and use of the Greek theater building and its connection to the Dionysus cult and festivals with musical and drama competitions. Next, scientific context is discussed as a background regarding the highly skilled architects who designed these theaters. The 4th century B.C.E. is characterized by the blooming of the sciences, especially mathematics, strongly stimulated by Plato's Academy near Athens. The architecture of the theater changed within this century. While earlier theaters had mostly rectilinear seat-rows, symmetry and a stricter geometry started to characterize theater design. In this study, six theaters were selected for acoustical analysis: three of them with rectilinear shapes, and three of the well-known semicircular form. Acoustical analyses show that the archaeologically demonstrated shift in theater design from a simple rectilinear shape to the historically canonical semicircular shape was a way to increase theater capacity and at the same time improve the acoustics. Acoustical analyses reveal some of the design principles that can explain the excellent acoustics of these theaters and the applied knowledge of their designers.
... However, it turns out that restricting the presentation to mean values (average of all receiver positions) and reporting ranges of the standard deviation is well suited to visually support the major statements, so results will be reported in this "condensed form" in the following account. Figure 6 shows the mean values of the simulation results for the investigated room acoustical parameters and the Dietsch's echo criterion [37] percentages of transmission paths with EK ! 1.5 for the three individual measures (fully absorbing facades; absorbing balcony soffits; absorbing inner courtyard floor) compared to the situation without measures (fully reflecting inner courtyards). ...
Residential perimeter blocks can shield traffic noise, but the acoustical quality may be sub-optimal in the inner courtyards. This study investigated how effective sound-absorbing facade surfaces and balcony soffits as well as an absorbing floor (lawn) influence the acoustical quality in inner courtyards. Room acoustical simulations were carried out for eight generic and two real-world models with very large numbers of transmission paths. Facades (reflecting, fully absorbing, partially absorbing), balcony soffits (reflecting, absorbing) and courtyard floor (reflecting, absorbing) were varied. A range of room acoustical parameters were evaluated, namely, reverberation time T20, early decay time EDT, strength G, speech transmission index STI, and Dietsch’s echo criterion EK. The simulations revealed that fully absorbing facades are an effective measure to improve the acoustical quality in inner courtyards, while partially absorbing facades result in smaller improvements. In fact, each additional storey of absorbing facades further improves the situation. In the case of non-absorbing facades, absorbing balcony soffits or an absorbing floor in the inner courtyard are not very effective as individual measures and may even increase disturbances due to echoes. The same holds true for situations with absorbing facades. Their feasibility should therefore be clarified for the individual situation in question.
... Makrinenko (1986) stated that the critical delay difference depends on the characteristics of the signal such as frequency content and temporal behaviour. On the other hand, an echo evaluation method based on the measured impulse response accounts for the ratio between the shift of centre time due to successive reflections and the delay of these reflections (Dietsch and Kraak, 1986). Other scholars based their approach on modulation-transfer a) Email: dario.dorazio@unibo.it ...
Central-planned halls are highly widespread in the historical architectures of the Western world, such as rotundae, Christian baptisteries, and Roman tombs. In such halls, whispering galleries, flutter echoes, and sound focusing are the acoustic phenomena mainly investigated by scholars. Instead, modal behaviour and free path distribution are generally less treated in literature. The present study explores the modal density at low frequencies and the relationship with the most recurrent free path lengths in three historical nearly circular spaces, here assessed as case studies. Acoustic measurements allowed the collection of objective experimental data, i.e., room impulse responses and the resulting room acoustics criteria. Wave-based numerical models allowed for the investigation of the eigenfrequencies distribution, while the free paths trend has been experienced through ray-based models. The main outcomes of both analyses show the prominence of the circular modes, rather than the diametral and the elevation ones. Moreover, the mean free path calculated using ray-tracing proves to be higher than the theoretical value commonly assumed for any kind of shape. The consequent longer reverberations compared to halls with other shapes and the same volume justify the significant support historically provided to sound signals by circular halls.
... Nevertheless, in open spaces, this parameter, which a priori does not differentiate between early and late sound, becomes particularly relevant, being also useful to detect the presence of late reflections or echoes (Paini, Gade, & Rindel, 2011;Rindel, 2023). The very low values obtained at the studied sites indicate the absence of late reflections and reverberant energy, suggesting that mainly the direct sound and very early reflections, presumably from nearby rocks, reach the listeners in that area (Dietsch & Kraak, 1986). In any case, the absence of a proper reverberant tail at the surveyed sites indicates that these sites can be considered "dry" in terms of sound perception, potentially facilitating speech transmission (Ando, Okura, & Yuasa, 1982). ...
In this article, the potential of archaeoacoustics for understanding past communities is discussed by looking at a range of acoustic parameters. Our case study is the Urkosh rock art area in the Ongudai district, Republic of Altai (Russia). The rock art of this area dates possibly from the Upper Palaeolithic and definitely from the Early Bronze Age (second half of the third millennium BCE). There are important periods in the Early Iron Age (first half of the first millennium BCE) and the medieval era, after which there are later additions up to the present day. Major and minor sites were tested, as well as some with no art. The results obtained from the tests conducted using the impulse response method indicate high values for sound clarity not only in the rock art sites but also in at least one nearby panel without rock art. Although these results cannot explain why rock art was produced precisely in specific locations, they objectively describe the acoustic conditions under which particular intangible cultural practices were probably organised in them. In particular we focus on storytelling and music, cultural practices for which there is a wealth of information in the ethnographic sources written about the area.
... In general, the IRs captured at the Bacinete core rock art area show only a few early reflections after the arrival of the direct sound due to the rock formations, and almost negligible scattered sound energy caused by the landscape 100 ms after excitation. No late reflection that could cause an echo in any of the impulse responses registered is identified, and neither can any echo be discerned for speech or music according to the Dietsch and Kraak echo criterion [58]. Furthermore, as sound scattering depends on geometry, the irregular shape of the rock blocks avoids flutter echoes due to parallel walls, despite their proximity. ...
This article belongs to the Special Issue Acoustics, Soundscapes and Sounds as Intangible Heritage: https://www.mdpi.com/journal/acoustics/special_issues/Acoustics_Soundscapes_Intangible_Heritage
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In the last few years, archaeoacoustic studies of rock art sites and landscapes have undergone significant growth as a result of renewed interest in the intangible aspects of the archaeological record. This article focuses on the acoustic study carried out in the rock art complex of Bacinete, Cádiz (Spain). After describing the archaeological site and its importance, a representative set of monaural and spatial IRs gathered onsite is thoroughly analysed to explore the hypothesis that the sonic component of the site played an important role in how prehistoric people interacted with it. Additionally, we briefly discuss the challenges of analysing the acoustics of open-air spaces following the recommendations of the ISO 3382-1 guidelines, a standard developed not for open-air spaces, but for room acoustics. The results obtained confirm the favourable acoustic conditions of the Bacinete main shelter for speech transmission. The different subjective acoustic impressions obtained in a somewhat similar shelter located nearby, Bacinete III, are also explained, alluding to a lesser degree of intimacy felt in the latter.
... The energy-time curves are quite diffuse; more so than expected in an open-air place. In fact, the echo criterion by Dietsch and Kraak [50] EC (1,14) of every measurement was 0.70 averaged, with a maximum of 0.89. For 10% of the audience to perceiving an echo with the music, a value of 1.5 would be needed. ...
This paper analyses the acoustic behaviour of the Palace of Charles V from a room acoustics perspective but also ponders the uniqueness of the space and its ability to engage and enhance the audience experience. The Palace of Charles V is a relevant part of the historical heritage of Granada. It has an architectural but also an acoustic uniqueness that deserves research. A measurement campaign was made to calculate parameters such as T30, IACC, C80 or Gm, and to explain the behaviour of the Palace. The BQI is quite high, but the late part of the impulse response (t > 80 ms) has strong unwanted reflections causing low clarity (C80) and listener envelopment (LEV). Nevertheless, the Palace is a successful concert venue with good feedback from musicians and the audience.
... The focusing of reflections from the concave seating arrangement is clearly seen in Fig. 2, but there are also reflections from the concave diazoma via the canopy above the stage, and late reflections from the colonnade surrounding the theatre. The calculated impulse response in the latter position shows a clear echo, see Fig. 4. In order to make it possible to locate positions with echo problems, the echo criterion suggested by Dietsch & Kraak [4] has been implemented in ODEON version 11. As an example Fig. 5 shows the echo-curve in the same position as the impulse response in Fig. 4. The echo parameter has a value above 1.0, which means that more than 50% would evaluate this as a clearly audible echo when listening to speech. ...
Ancient Greek and Roman theatres are often considered acoustically perfect. However,
the semicircular shape of the audience area in theatres built from hard and sound
reflective materials may cause acoustic problems, and there is also evidence that the
ancient architects were well aware of this. The Roman architect Vitruvius describes in
his books on architecture four different kinds of sound reflections in a theatre, one of
them called ‘circumsonant’ which is an acoustic phenomenon that we today would
name a focused echo. Computer simulations of some examples of ancient Greek and
Roman theatres confirm that this can be a real problem at some places in the audience
area. For this study is used the echo criterion for speech as suggested by Dietsch &
Kraak; this is implemented in the room acoustics software ODEON, and that makes it
easy to identify positions with echo problems. A possible solution to these echo
problems could be the introduction of sound absorption in the vertical, concave surfaces
in a way similar to that described by Vitruvius for the sounding vessels, i.e. in niches
between the seats arranged in a horizontal range halfway up. Reading the description by
Vitruvius in this light, it makes good sense if the vessels are supposed to act as sound
absorbing resonators. Since they are efficient in a narrow frequency band, it also makes
sense to apply different sizes with resonance frequencies distributed over two octaves,
as described in detail by Vitruvius. Finally, it is noted that the principle of installing the
sounding vessels in the theatre comes from older Greek references; obviously Vitruvius
had no experience with the vessels himself, but he refers to a scheme based on music
theory made by Aristoxenus (4th century BC), who was a famous Greek philosopher and
expert in music theory.
... Finally, the echo potential is evaluated by using the methods of Dietsch and Kraak [12]. The simulations of the room requires acoustical parameters such as absorption coefficients of the interior materials. ...
A vacant unit, once used by a Portuguese Deli, was converted to a bar/music room in Toronto. The unit was divided into two spaces along its north-south axis. The western portion was designed as a music room that would provide a performance space from a solo artist to a Jazz combo to a small rock band. The eastern part was designed as a regular bar/dining area. The plan also called for a microbrewery unit at the back of the unit. The bar music can be loud, while the music room can be pianissimo to forte depending on the type of performance. The acoustical design aspects are critical for the music room. In addition, the acoustical separation between the two spaces is equally important. The music room/bar is currently in use. The design results are compared to actual field measurements. The results showed that the music venue performed satisfactorily. The acoustical separation between the music venue and the bar/restaurant was better than expected other than an installation deficiency of the south side sound lock doors. The background sound along the northern portion was NC-35 or less. However, the southern portion's background sound exceeded NC-35 due to the hissing of the return air grille. The acoustical design and the performance results of the music venue-bar/restaurant are presented in this paper.
... Following a methodology already experimented in [2], in case of omnidirectional source the elements were estimated by means of Sound Strength (G), to assess the reinforcement of the propagation of the sound, Clarity (C 80 ), to evaluate the possibility of execution of other kind of performances; SPL and C 50 were analysed in case of directional source with raised human voice frequency spectrum. Echo Criterion (EC) by Dietsch and Kraak [7] was also considered in order to detect potential echo problems at low frequencies, typical in ancient theatres [8]. Figure 4 shows a resume of the elements analysed. ...
A research conducted on the contemporary use of ancient theatres is presented, focusing on sustainable solutions for passive acoustics and artificial lighting devices. The case study is the theatre of Syracuse, well known as archaeological tourist attraction and as traditional stage for theatrical events. A retrofit was suggested to avoid the use of loudspeakers in the theatre during representations, through the selection of the best performing orchestra shells. For the lighting part, the study focused on the theatre as archaeological site, improving the monumental light system present in the theatre from the maintenance and energy saving points of view.
... The word generalized is used because not h(t) directly, but its p-th power is involved. Interestingly, a similar term appeared in the calculation of the room acoustic parameter 'echo criterion' [9] but with a dierent purpose, integration intervals and exponents. Note that in this calculation there is no regression involved but the reverberation time is directly obtained by a forward integration from the impulse response. ...
This paper presents the application and a method that calculates the reverberation time based on Lp-norms. generalized measures of the room impulse response (RIR). without using regression on decay curves. The reverberation time in this approach is a function of a parameter, and is constant only in a perfectly diffuse space; therefore the method may present useful information beyond the decay time itself. Properties of this method using theoretical and real-life RIRs are examined in cases of wide-band and sub-octave-band calculations. Correction methods for the finite support of the R IR . as well as for the effects of stationary background noise are presented and the connection to previous methods is shown.
... Numerous publications came out of the research groups leaded by Erwin Meyer (Göttingen), Walter Reichardt (Dresden) and Lothar Cremer (Berlin). From the main results in famous publications and dissertations just some are listed here with some keywords: University of Göttingen: E. Meyer et al.: "Simulation of room acoustics by electroacoustic systems" [10], M.R. Schröder: "Frequency curves" [11], M.R. Schroeder: "Integrated Impulse Response" [12], H. Kuttruff: "Statistics of frequency curves" [13] Technical University Dresden: W. Schmidt, O Abdel Alim, W. Schmidt: "Clarity" [14], L. Dietsch, W. Kraak: "Echo perception" [15] Technical University Berlin: H. Wilkens, P.Lehmann, D. Gottlob, K.F. Siebrasse: "Correlation subjectiveobjective" [16][17][18][19], R. Kürer: "Centre time" [20] With this pioneering work, room acoustics was clearly taken out of the influence of black magic. ...
Room acoustics has a scientific interdisciplinary concept which will be further developed in future. During the last century, several dimensions of the overall listening impression in concert halls were identified which show a good correlation with corresponding objective measurement data. It can be summarized that the three most important factors (loudness, reverberance and spatial impression) explain most of the statistical variance when comparing the acoustic conditions in auditoria. But some questions remain, particularly for stage acoustics, for dependencies within the quantities and for the overall impression. In applied room acoustics, progress can be seen concerning modeling and simulation on the one hand, and impulse response measurements on the other. Apart from the perceptual factors of room acoustics, another crucial point is the listener's sensitivity to changes in a sound field in regard to those subjective aspects. In the end, the uncertainties of simulation and measurement results must be compared with the just noticeable differences, jnd, of hearing in rooms. Thus, further cooperation of room acoustics with psychoacoustics and audio engineering is expected to stimulate more ideas and innovation in research and concert hall design.
... The usefulness of the data would be increased through performing the measurements using a Dummy Head. Echo-criteria and objective analysis procedures similar to those proposed by Dietsch and Kraak (Dietsch and Kraak -1986) and Niese (Niese -1961) can best be assessed through data taken in a dummy head. For these reasons, more detailed analysis of the impulse responses was not undertaken unless there was some impetus for further analysis through other areas of analysis and consideration of the data. ...
... Se ha calculado también el riesgo de eco usando el criterio Ek_grad [9], y no se ha detectado éste en ninguno de los dos supuestos, aunque parece evidente, a la vista de las figuras 17 y 18, que cuando receptor y fuente están alejados dicho riesgo aumenta. Se podría interpretar esto como que la aparición de ecos es una cuestión mucho más compleja de lo que se entiende habitualmente [6] [10] [11]. ...
The echo phenomenon based on the definitions given in the literature of different authors will be discussed. Individual cases raised as typical risk situations echo using simple geometric tools will be analyzed by studying the set of reflections in every possible situation about the temporal (150-300 ms), and energy behavior roughly. Impulse response is presented in two conflicting premises: "Llotja S. Jordi" in Alcoy (Arquit: S. Calatrava) and "Plaza de toros/Arena" Villena (Arquit: J.C. Carrión).
... In order to makei tp ossible to locate positions with echo problems, the echo criterion suggested by Dietsch and Kraak [12] has been implemented in ODEON version 11. As an example Figure 7s hows the echo-curvei nt he same position as the impulse response in Figure 6. ...
The ERATO project was a three-year research project financed by the European Commission under the Fifth Framework INCO–MED Program (2003–2006). The acronym refers to the project title: Identification, Evaluation and Revival of the Acoustical Heritage of Ancient Theatres and Odea. The ancient Greek and Roman theatres are famous for their excellent acoustics. However, it is not generally well known that different kinds of theatres were built, for different purposes and with different acoustical conditions. The development of the Roman theatre types (theatre, odeon and amphitheatre) particularly in the first Century BC is briefly outlined. One aim of the ERATO project has been to investigate the acoustics of the open air theatre and the odeon, using virtual reconstructions be means of computer models of the spaces, completed in accordance with available archaeological information. Musical instruments and short pieces of music have been reconstructed and recordings have been used for auralisation of some theatre scenarios. Ancient Greek and Roman theatres are often considered acoustically perfect. However, the semicircular shape of the audience area in theatres may cause acoustic problems, and there is also evidence that the ancient architects were aware of this. The Roman architect Vitruvius mentions in his famous books on architecture four different kinds of sound reflections in a theatre, one of them called 'circumsonant' which is probably the acoustical phenomenon that we today would name a focused echo. Computer simulations of some examples of ancient Greek and Roman theatres confirm that echo can occur at some places in the audience area. A possible solution to these echo problems could be the introduction of sound absorption in the vertical, concave surfaces in a way similar to that described by Vitruvius for the sounding vessels, i.e. in niches between the seats arranged in a horizontal range halfway up (in the diazoma). Thus it makes sense if the vessels were supposed to act as sound absorbing resonators, although the number of resonators is far from sufficient for having any real effect. The idea and principle of installing resonators in a theatre comes from Aristoxenus (4th century BC), who was a famous Greek philosopher and scholar in music theory. It is concluded that the sounding vessels had no practical importance in the Roman theatres, and Vitruvius was not up-to-date in his writing on theatre design, but relied heavily on older, Greek references.
This article explores the presence of shamanism in the Karakol valley, analysing its historical timeline from prehistoric to modern times. Scholarly opinions vary, suggesting origins from the Neolithic to the modern era, with clearer depictions emerging in the 18th and 19th centuries. Acoustic tests conducted in four areas associated with shamanic practices revealed inconclusive results due to their location in an open-air environment. However, accounts of intense auditory experiences during shamanic rituals suggest that, even if acoustics may be used in some occasions, there are other alternative means of emotional control. It is argued that the lack of significant acoustic effects in the tested sites does not rule out the possibility of shamanic rituals. The discussion also delves into the representation of shamans in rock art and the interpretation of results from acoustic tests, considering factors like reverberation and sound clarity. This study highlights the complex interplay between shamanism, sensory experiences and ritualistic practices in ancient societies.
A circus-theater is a particular type of theater space. It is mainly characterized by the possibility of interchanging the typical configuration of theater, where the stage house is settled in quasi-circularly to the audience area, to a circus configuration, in which the stage is totally surrounded by the audience area. Despite the abundant literature that tries to objectively and subjectively assess the acoustic characteristics of several theater spaces, there is scarce information about the acoustics of circus-theaters.
This work is a first approach to the acoustic characterization of such theater spaces. The main goal of this paper is to acoustically evaluate a circus-theater; for that, objective “in situ” measurements have been carried out considering both stage configurations. ISO 3382-1 has been taken as the guidance to select the acoustic parameters to measure, together with some other well-known additional parameters of room acoustics.
Measurements and characterization processes have been applied to the Circus-Theater of Albacete, as this is one of the few Spanish circus-theaters that still offers the possibility of using both stage configurations. Results allow to acoustically characterize a preliminary description of this kind of theater spaces, as well as comparatively study the theater and circus configurations from an acoustic point of view.
During the 17th, 18th, and 19th centuries, a room acoustic theory arose with design goal to avoid echoes from occurring by quantifying the perception threshold between direct sound and 1st-order reflections. The room acoustic design of the large 19th century concert hall Palais du Trocadero (1878–1937) was based on this theory. As the resulting acoustics were notoriously poor, an attempt was undertaken in 1909 to correct the acoustics by installing additional absorbing material following the same “echo theory” design approach. In order to study the consequences of this design theory, four configurations of this concert hall have been numerically reconstructed. Through calibrated simulations, it was shown that in the case of the Palais du Trocadero, design decisions based on “echo theory” had a positive effect on the acoustics; however, due to the many curved surfaces, echoes, and sound focusing, the acoustic conditions remained poor.
Church “Nuestra Señora de la Paz” suffered from an excessive reverberation (4 seconds at mid-frequencies) and an ill-suited sound reinforcement system. Measurements of the Speech Transmission Index (STI) in the congregation area indicated that speech intelligibility was greatly impaired. Thermal insulation on the roof was insufficient and impacted in air conditioning costs. Renovations included the design of a sound-absorbing and thermally insulating covering in the roof area. Subsequent measurement of room acoustic parameters showed that the proposed goals were met. A new sound system, which increased speech intelligibility and audio quality substantially, was designed and tested. The possible appearance of acoustical defects after the renovation, such as echoes and flutter echoes, was studied using objective tests on the measured Room Impulse Responses (RIRs).
Church “Nuestra Señora de la Paz” is located in Pilar, province of Buenos Aires, Argentina. It has an octagonal floor plan and an internal volume of 2500 m³ with bare sidewalls and little ornamentation. Excessive reverberation (4 seconds at mid-band frequencies), and an inappropriate sound system impaired speech intelligibility making ceremonies almost unintelligible. The church also suffered from thermal problems due to insufficient thermal insulation on the roof. Measurements (reverberation time, impulse responses and STI) were carried out and subsequent analysis revealed the significance of these problems. A holistic acoustical and thermal renovation was proposed and a new sound system was designed to address these issues. Subsequent measurements validated the effectiveness of the proposed renovations.
Die traditionelle Aufgabe der Raumakustik besteht darin, die Bedingungen zu schaffen oder zu formulieren, die in einem Raum eine möglichst gute akustische Übertragung von einer Schallquelle zu einem Zuhörer gewährleisten. Die Objekte der Raumakustik sind somit insbesondere Versammlungsräume aller Art wie Hör- und Vortragssäle, Sitzungsräume, Theater, Konzertsäle oder Kirchen. Schon jetzt sei darauf hingewiesen, daß diese Bedingungen wesentlich davon abhängen, ob es sich bei den zu übertragenden Schallsignalen um Sprache oder Musik handelt; im einen Fall ist eine möglichst gute Sprachverständlichkeit das Kriterium für die Qualität der Übertragung, im anderen dagegen hängt der Erfolg raumakustischer Bemühungen von der Erreichung anderer, weniger leicht quantifizierbarer Gegebenheiten ab, nicht zuletzt auch von den Hörgewohnheiten der Zuhörer. Jedenfalls gibt es die schlechthin „gute Akustik“ eines Raumes nicht.
Most room acoustic parameters are Energy/Time based: “How much sound energy is received during a certain period of time?” These established criteria are founded on a huge amount of knowledge, but fulfilling every criterion will not necessarily secure an excellent concert hall. The Energy/Time approach might lead to strange trains of thought like: “Anything happening before 50 ms is good for the clarity of speech.” Of course, a good acoustician does not think this way, but today, with modern light weight-measuring equipment and “apps,” we should take a closer look into cognitive and psychoacoustic aspects of sound in rooms and spaces: “Acoustics Between Times” (how the sound events are distributed within the different time limits) and “Acoustics Between Criteria” (how the standardized criteria might “mask” important information on the perception of room acoustics by putting too much weight on reproducibility, mean values, and standard deviations; demands that might lead to somewhat uninteresting measurements). In this article, we will look into psychoacoustic/cognitive aspects of how the reflections are distributed in time; how an astute listener or musician can use handclaps and other personal, impulsive sounds to investigate important details of room acoustics; and what we can learn from the real experts of “seeing a room with the ears,” namely persons who are blind.
Known in the past for its spectacular acoustic characteristics, the ancient theatre keeps today an important role as a modern stage: during the summer season many important theatrical events are organized in the frame of its ancient ruins, keeping alive a tradition that attracts people all around the world. But, without doubts, the actual conditions for the audience are deeply changed, affected by “modern” noises and damaged situation of the theatre itself. The insertion of the scenery elements has also to be considered as a variable that can modify the sound propagation in the theatre, with better or maybe worst results. In this article a research conducted on the acoustic perception of the audience of the Greek theatre of Syracuse is presented. A parametric study realized through a technical software (Odeon ® version 12.1) has been performed considering different scenery conditions, from the empty theatre and by adding different scenic elements to evaluate their influence on passive acoustics. In a first study, the three-dimensional model considered was built based on the scenery realized by OMA in 2012 for the 48th Edition of Classical Plays at Syracuse’s Theatre. Lately, the comparison between the condition with and without the scenery allowed establishing a few acoustic guidelines for the scenic design. The result of these first two studies was the proposition of scenic elements that allow the preservation and the improvement of the original acoustic apparatus.
In this work, the comparison through auralization of the different conditions of the theatre
provides interesting suggestions on the way toward an efficient scenic design and aims at satisfying the audience acoustic needs and at a deeper fruition of the theatrical experience nowadays. In particular five different conditions were tested: I. Empty condition, II. OMA’s scenery, III. A scenery based on the re-elaboration of the historical configuration, IV. A scenery developed for modern theatrical performances, V. Empty condition with loudspeakers.
In den folgenden Abschnitten werden die Besonderheiten der Messtechnik für raumakustische und beschallungstechnische Anwendungen
zusammengestellt.
Computer simulation for precalculation of acoustic properties of concert halls and theatres has become more and more common in the course of the last 10 years. While in the past scale models (1:10 to 1:20) were used to evaluate the acoustic properties of a hall under construction, now computer models supply results faster and more conveniently. But scale models are still being used in parallel because of the following limitations of com- puter models: • Certain incorrectness with regards to scattering effects • Unsolved solution for diffraction behaviour • Limitation in computer-model resolution The advantages and disadvantages of computer simulation in comparison to scale-model measurements will be shown. Examples will demonstrate the growing superiority of computer simulation during the acoustic design phase. Limits of computer auralization will be explained. Knowledge about the acoustical design of halls and open-air spaces has been around for 2000 years /1/. It has been scientifically underpinned especially in the last 200 years. For enabling the acoustical properties of such rooms to be more accurately determined beforehand, room-acoustical investigations in physical models have been carried out since the beginning of the 20th century /2,3/. The signifi- cance of these investigations has until now remained unquestioned. With the availability of mainframe computers such predeterminations are now carried out by way of computer simulations and no longer by dint of physical models. A trailblazing paper in which Krokstad /4/ first described the use of main- frame computers for the precalculation of the acoustical properties of a hall was published in 1968. With the introduction of personal computers in the middle of the 80ies of last Century the use of com- puter programs for precalculating acoustical properties has increased immensely, so that now there are available, in addition to the programs developed by universities, a series of highly efficient commer-
A simple method to detect audible echoes is proposed as an objective criterion for room acoustics. This method evaluates the perceptibility of sound reflections that are generated by an impulsive sound source and identifies from reflectograms harmful reflections perceived as echoes. Particularly with this method, the masking effect of reverberation is taken into consideration, which cannot be treated sufficiently by the existing objective criteria. The applicability to room acoustical design is verified by evaluating the impulse responses measured in real halls where audible echoes occurred. It is shown that the proposed method detects audible echoes at an accuracy of more than 90% and would be suitable for practical use.
Das Schallfeld einer Schallquelle breitet sich in alle Raumrichtungen annähernd strahlenförmig aus. Der Anteil des Direktschalls
an diesem Schallfeld unter Vernachlässigung von reflektiertem und gebeugtem Schallanteil wird als freies Schallfeld bezeichnet. Da die meisten Schallquellen eine schallreflektierende Unterlage benutzen, ist es nach (Fasold et al. 1987) üblich,
auch dann von einem freien Schallfeld zu sprechen, wenn die Schallquelle auf einer großen, schallreflektierenden Grundfläche
steht. Für Schallquellen in Räumen überwiegt in größerer Entfernung von der Quelle der Anteil von gebeugtem und an den Wänden
reflektiertem Schall. In einem Raum mittlerer Größe mit einem Volumen von 800m3 produziert ein Schallsignal innerhalb von nur einer Sekunde etwa 200.000 Reflexionen an den Wänden, die in den Raum zurückgeworfen
werden. Da in diesem Teil des Schallfelds sowohl der örtliche Schallpegel als auch die Ausbreitungsrichtungen statistisch
weitgehend gleichverteilt sind, wird es als diffuses Schallfeld bezeichnet.
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