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Dammerud J.,Nordasveien 65 | Barron M.,Fleming and Barron | Kahle E.,Kahle Acoustics
Building Acoustics | Year: 2011

At present the most common measures for assessing stage acoustic conditions on concert hall stages are the Support measures - STearly and STlate. These measures are based on monophonic omnidirectional responses obtained at 1 m from the sound source, on a stage without a full symphony orchestra (or similar group of people) present. Both objective and subjective studies have been conducted, the latter using questionnaires with several orchestras and dialogue with musicians. Objective studies involved measurements on real stages of the Support measures and other acoustic measures such as T, EDT, C80, G7-50, Ge (G 0-80) and Gl(G80-) as well as a set of proposed architectural measures. These have been complemented with analytical as well as scale and computer model investigations into sound behaviour on both empty and occupied concert stages. The major results from these studies are presented in this paper along with a discussion of alternative approaches for assessing stage acoustic conditions. One important result concerned the relevance of directions from which early reflections arrive regarding perceived ensemble conditions, an objective factor not assessed by the Support measures.


Vehvilainen S.,Akukon Oy Consulting Engineers | Tishko D.,Akukon Oy Consulting Engineers | Wulfrank T.,Kahle Acoustics | Rozanov S.I.,Moscow Conservatory
20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society | Year: 2010

The Moscow P. I. Tchaikovsky Conservatory is situated in a 19th century building located in the center of Moscow. The Great Hall (Bolshoi Sal) of the Conservatory is probably the most loved concert hall in Russia by both musicians and audience, both for its visual appearance but not least for its acoustic conditions. The hall will be renovated for the Tchaikovsky competition in 2012. In connection with the renovation design, the existing acoustic conditions in the hall have been assessed, both by means of objective impulse response measurements in the hall as well as by questionnaires handed out to orchestra and audience members. In addition a 1:20 acoustic scale model has been built and tested, and the geometry of the hall has been studied in computer models. This paper presents the acoustic conditions of the Great Hall based on the measurement, modelling and listening studies and aims at providing some insight to the acoustic community as to why this hall is so successful.


Kahle E.,Kahle Acoustics | Wulfrank T.,Kahle Acoustics | Jurkiewicz Y.,Kahle Acoustics | Brulez J.,Kahle Acoustics
Proceedings of Forum Acusticum | Year: 2014

Loudness is a major concern for music rehearsal rooms, probably even more than reverberation time. This has implications for both the quantity and the location of acoustic absorption-The smaller the rooms the more highly dampened they need to be, and in order to make them as reverberant as possible it is beneficial to locate absorption as close as possible to the sound sources, which normally means in the lower part of the room. Furthermore, this has implications on variable acoustics, or "differentiated acoustic quality" as a function of the users: louder instruments need more damping and therefore less resonance, while for the same acoustic volume, a more resonant and reverberant acoustic quality can be acceptable and beneficial for softer instruments like strings and woodwinds.


Jaruszewska K.,KFB Polska | Rychtarikova M.,Catholic University of Leuven | Wulfrank T.,Kahle Acoustics | Jablonska J.,Wroclaw University of Technology | Boeck M.,Gfai Technology
Energy Procedia | Year: 2015

This presentation introduces a didactic tool ArAc-Multibook of Architectural Acoustics (an interactive publication) whose main objective is to innovatively fill the gap in technical literature and to increase architects' awareness about the role acoustic comfort plays in the life of human beings. The ArAc project demonstrates an innovative approach to education and professional development of architects in the area of acoustics. Professional books on architectural acoustics are aimed chiefly at readers with mathematical or technical background, usually graduates of electronics or physics faculties. Such studies have only a limited usefulness to architects, who intend not to study architectural acoustics as a separate area of knowledge, but to search for an inspiration regarding acoustically correct architectural solutions. The materials included in the multibook are to help architects in correct and unassisted solving of common and unsophisticated noise protection and interior acoustics problems. This type of knowledge is most useful in conceptual design works related to architectural acoustics, as well as in mutual understanding of different priorities that architects and acoustician working together may have. ArAc-Multibook of Architectural Acoustics is a four-language application for mobile devices (tablets, smartphones both for iOS and Android) and on website. The Multibook is the first application of this kind in the form of a acoustics manual for architects enriched with audio, image galleries, animations, instructional videos and elements of interactive infographics. © 2015 Published by Elsevier Ltd.


Wulfrank T.,Kahle Acoustics | Jurkiewicz Y.,Kahle Acoustics | Kahle E.,Kahle Acoustics
Building Acoustics | Year: 2014

Curved surfaces have a major influence on the propagation of sound in rooms. Convex surfaces always lead to attenuated reflections spread out over a larger area, while concave surfaces create either amplification or attenuation of reflections, depending on the source and receiver positions relative to the curved surface. Contemporary architecture often involves extensive use of both convex and concave surfaces. Therefore, acoustic consultants need to be able to quickly gain a thorough understanding of a given curved geometry, and judge to what extent the arising focusing will be either benign or problematic (due to focusing, inhomogeneous sound distribution or flutter echoes).The advent of NURBS-based 3D software (e.g. Rhino5) has made it possible to carry out very precise geometrical raytracing on curved surfaces, revealing their geometrical coverage. As a further refinement, a differential raytracing technique is proposed, allowing the straightforward calculation of the amplification or attenuation created by a given curved surface. This purely geometrical technique can also be applied to higher order reflections, in order to help identify flutter echo problems created by multiple reflection paths involving concave surfaces.Practical examples of halls with significant curved geometries will be given to illustrate the use of this approach, including Wigmore Hall, London and Wuxi Grand Theatre.


Several acousticians have attempted to define a complete set of factors describing room acoustic quality, based on laboratory and/or real hall listening tests. After finishing a PhD thesis on room acoustic quality, the author has worked on new constructions of performance spaces, renovations as well as optimizations of existing spaces and the question can now be asked whether the widely used set of objective criteria and perceptual factors proves sufficient to describe the problems and challenges encountered. When working on high-quality acoustic spaces, the commonly used set of acoustic criteria is insufficient to describe all aspects and problems. Further descriptors are required with respect to both acoustic measurements and perceptual factors. Proposals for additional acoustic criteria and their link to the architecture of a space will be given, aiming to better describe the signature of a room with respect to both source presence and room presence. The concept of "stream segregation" into source presence and room presence is confirmed, but for both the "source" and "room" parts not only the magnitude (strength) needs to be considered but equally more detailed aspects like "lateralness" and direction of arrival, i.e. what could be called the "spatial center of gravity". For example, changing the spatial center of gravity of the reverberation has very strong perceptual consequences. Another aspect that often tends to be neglected is the question of orchestral balance (for audience members but equally for musicians on stage) that can strongly be influenced by acoustic design decisions.


Wulfrank T.,Kahle Acoustics
Proceedings of Meetings on Acoustics | Year: 2013

Vibration of (wood) surfaces plays a significant role in concert hall acoustics, as confirmed by musicians and music lovers. Many acoustic engineers, on the other hand, tend to have strong reservations against vibrating surfaces, and usually try to minimise surface vibration in order to maximise RT and airborne Strength (G) at bass frequencies. This has lead to a generally accepted preference for massive and stiff surface constructions in new halls. Problems have been known to occur when this general guideline was also applied to the design of wooden floors, in particular stage floors. Despite some good scientific research in this field, a big gap still remains between the vibro-acoustic behaviour of wooden floors and subjective preferences of musicians and audiences. This paper further explores the role of vibrations in concert hall design, and the need for balancing surface reflectivity versus vibration transmission. Recent experiences, including the new Konserthus in Stavanger and the renovation of the Bolshoi Hall of the Moscow Conservatory, will be described as well as vibration measurements carried out on a number of existing stage floors. Some implications for the design of wooden floor constructions will be discussed. © 2013 Acoustical Society of America.


Jurkiewicz Y.,Kahle Acoustics | Wulfrank T.,Kahle Acoustics | Kahle E.,Kahle Acoustics
Journal of the Acoustical Society of America | Year: 2012

Supplying sufficient early reflections to audience members is an important prerequisite to good acoustic quality in performing arts spaces. However, the relationship between the geometry of a room and its acoustic efficiency in terms of early energy has rarely been investigated using basic geometrical principles. The present study demonstrates the possibility of predicting the average value of early reflected energy across the audience area using solid angles. The formulas obtained display the influence of various factors on average early energy; in particular, the direction of arrival of early reflections is found to play a significant role, which highlights interesting implications for the acoustic design of concert halls. © 2012 Acoustical Society of America.


PubMed | Kahle Acoustics
Type: Journal Article | Journal: The Journal of the Acoustical Society of America | Year: 2012

Supplying sufficient early reflections to audience members is an important prerequisite to good acoustic quality in performing arts spaces. However, the relationship between the geometry of a room and its acoustic efficiency in terms of early energy has rarely been investigated using basic geometrical principles. The present study demonstrates the possibility of predicting the average value of early reflected energy across the audience area using solid angles. The formulas obtained display the influence of various factors on average early energy; in particular, the direction of arrival of early reflections is found to play a significant role, which highlights interesting implications for the acoustic design of concert halls.

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