scholarly journals Pre-Sabine Room Acoustic Guidelines on Audience Rake, Stage Acoustics, and Dimension Ratios

Acoustics ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 235-251
Author(s):  
Barteld N. J. Postma ◽  
Evan Green ◽  
Eckhard Kahle ◽  
Brian F. G. Katz
Keyword(s):  
Art Museum ◽  
Scale Model ◽  
Perception Threshold ◽  
First Order ◽  
Acoustic Design ◽  
Concert Halls ◽  
Length Width ◽  
Opera Houses ◽  
Current Practices

Prior to Sabine’s work on the Fogg Art Museum and Boston Symphony Hall, several numerical guidelines had been developed and applied to the design of rooms with specific acoustic demands such as theatres, concert halls, and opera houses. Previous papers have discussed guidelines based on the following principles: voice directivity, which was employed in the design of at least 11 rooms; “echo theory”, which quantifies the perception threshold between direct sound and first order reflections in order to prevent echoes from occurring, aiding in the design of at least 7 rooms and leading to the first known use of an acoustic scale model; and notions of reverberation, which influenced the design of at least 14 rooms. This paper discusses three additional pre-Sabine numerical guidelines that were used in room acoustic design: (1) audience rake, (2) stage acoustics and proscenium design, and (3) length, width, and height ratios. The origin of these theories, as well as examples of rooms in which they were applied, are discussed and compared to current practices in room acoustic design.

Modelling of Scattering from Balcony Fronts

2002 ◽  
Vol 9 (3) ◽  
pp. 219-231
Author(s):  
T. M. Chan ◽  
W. M. To
Keyword(s):  
Computer Simulation ◽  
Ray Tracing ◽  
Diffuse Reflection ◽  
Sound Field ◽  
Direct Wave ◽  
Practice Experience ◽  
Concert Halls ◽  
Distinguished Group ◽  
Opera Houses

Balconies are normally used in large auditoria such as concert halls or opera houses, to increase seating capacity or to give better view for a distinguished group of the audience. When ray-tracing based computer models are applied to study the acoustical quality of these auditoria, the alteration of the sound field due to balcony fronts is normally unobservable, because of the relative small size of the balcony fronts in the auditorium. Furthermore, most diffuse reflection ray-tracing methods are not based on direct wave acoustics but on an approximation of the scattering effect. In practice, experience shows that balcony fronts give additional warmth to music. This effect is more prominent when singers perform in traditional horseshoe shaped opera houses with multi-levels balconies. This paper describes modelling of scattering from balcony fronts using a theoretical wave approach, in which the incident wave front is not plane but spherical. A computer simulation illustrates the scattering of sound that takes place when the wavefront impinges on the surface of the balcony fronts.

scholarly journals Effect of Stage Volume Ratio on Audience Acoustics in Concert Halls

2020 ◽  
Vol 12 (4) ◽  
pp. 1370 ◽  
Author(s):  
Jin Yong Jeon ◽  
Rosa Seo ◽  
Hyun In Jo
Keyword(s):  
Computer Simulation ◽  
Simple Model ◽  
Volume Ratio ◽  
Acoustic Parameter ◽  
Acoustic Parameters ◽  
Design Factor ◽  
Acoustic Design ◽  
Critical Design ◽  
Study Results ◽  
Concert Halls

This report proposes the stage volume ratio (Vo/V) as an acoustic design factor for concert halls and presents an investigation of the dependence of the acoustic parameters of an auditorium on the stage volume through computer simulation. Firstly, the ratio of the stage volume to the total volume of a concert hall was defined as Vo/V through case studies of existing concert halls. It was verified using a simple model that the stage acoustic parameter STEarly and audience acoustic parameters G and C80 decreased, whereas, the reverberation time and early decay time increased with increasing Vo/V. Secondly, a computer simulation was performed for nine existing concert halls, while changing Vo/V from −20% to 30%. The room acoustic parameters exhibited the same patterns as suggested by the simple model. Vo/V significantly affected the bass ratio and bass index. A comparison of the effects of Vo/V and the sound absorption coefficient in nine concert halls revealed that Vo/V contributed approximately 15% to the reverberation and affected the bass characteristics more substantially. Thus, Vo/V is a critical design factor when determining the warmth of the audience acoustics. The study results could be used as a basis for acoustic design in the future.

scholarly journals Rearch on Electromagnetic Scattering from ocean covered by foams

2018 ◽  
Vol 173 ◽  
pp. 03082
Author(s):  
GAO Qian ◽  
YUE Hongwei ◽  
WANG Zhenxin ◽  
JI Yajun ◽  
LI Ximin
Keyword(s):  
Wind Speed ◽  
Radiative Transfer ◽  
Temperature Difference ◽  
Electromagnetic Scattering ◽  
Mie Theory ◽  
Ocean Surface ◽  
Scale Model ◽  
First Order ◽  
Scattering Coefficients ◽  
Back Scattering

Back scattering of ocean surface is investigated by considering the foams coverage on its surface. Firstly, by adopting modified two-scale mode and the vector radiative transfer theory, zero and first order scattering coefficients are obtained by solving VRT equations. Then, MIE theory is used to get the scattering from foams, and fraction of foams coverage is analyzed by changing parameters of wind speed and temperature difference of ocean-air. Finally, the modified two-scale model and algorithms are verified by comparing its results with measured results, and simulations of calculating back scattering from ocean surface with and without foams are carried out. The conclusion is obtained that wind speed has different influence on back scattering under different incident angles.

Room Acoustic Modelling Techniques: A Comparison of a Scale Model and a Computer Model for a New Opera Theatre

2011 ◽  
Vol 18 (3-4) ◽  
pp. 259-280 ◽  
Author(s):  
Jens Holger Rindel
Keyword(s):  
Satisfactory Agreement ◽  
Computer Simulations ◽  
Computer Model ◽  
Computer Modelling ◽  
Computer Models ◽  
Scale Model ◽  
Acoustic Design ◽  
Acoustic Modelling ◽  
Scale Modelling ◽  
Modelling Techniques

Today most acoustic consultants are using room acoustic computer models as a basis for their acoustic design. However, room acoustic scale modelling is still being used for the design in some major projects, although the costs and the time needed are significantly larger than those related to computer modelling. Both techniques were used by the author in a project for a new opera theatre; first the acoustical design was based on computer simulations using the Odeon software, and next a 1:20 scale model was built and tested. In the paper the results obtained with the two different modelling techniques are compared, and in general a satisfactory agreement has been found. The advantages and drawbacks related to each of the modelling techniques are discussed.

Crane Ship Response to Wave Groups

1991 ◽  
Vol 113 (3) ◽  
pp. 211-218 ◽  
Author(s):  
T. E. Schellin ◽  
T. Jiang ◽  
S. D. Sharma
Keyword(s):  
Continuous Wave ◽  
Amplitude Spectrum ◽  
Large Angle ◽  
Second Order ◽  
Scale Model ◽  
Ship Motions ◽  
Nonlinear Simulation ◽  
Wave Groups ◽  
First Order ◽  
Load Response

The motion response of a shear-leg crane ship lifting a heavy load in wave groups was investigated. The 9-DOF dynamic model incorporated hull motions coupled with nonlinear large-angle load swing and elastic stretch of the hoisting rope assembly. Hydrodynamic response forces and wave excitation forces were taken to be frequency dependent, and nonlinear mooring system restoring forces were allowed for. Closed-form linearized results about the system equilibrium state verified our nonlinear simulation algorithm; simulation results in comparison with scale model test measurements, our mathematical model. Wave groups were idealized in two different ways: 1) as continuous wave groups produced by pairs of beating waves of equal amplitude and slightly different periods, and 2) as isolated wave packets generated by superimposing a large number of regular wave components derived from a Gauss-modulated amplitude spectrum. Simulations show that hook load response, strongly coupled with ship motions, was mainly influenced by first-order wave-exciting forces. Low-frequency horizontal ship motions caused by second-order wave (drift) forces did not generally affect hook load response, i.e., first-order and second-order responses were independent.

scholarly journals Workers’ access to Swedish opera houses and concert halls, 1898–2019

2021 ◽  
Author(s):  
Staffan Albinsson
Keyword(s):  
Low Income ◽  
Cultural Policy ◽  
Social Inclusion ◽  
Symphony Orchestra ◽  
Ticket Pricing ◽  
Concert Halls ◽  
High Level ◽  
In The Beginning ◽  
Ticket Prices ◽  
Opera Houses

AbstractIn this study ticket prices to Swedish opera houses and symphony orchestra concerts are compared to wages during the 1898–2019 period. Both wages and ticket prices have increased continuously. The same kind of policy objectives concerning social inclusion of disadvantaged groups that were established in the beginning of the twentieth century is still proclaimed. The most favourable ticket pricing policies for buyers were used in the decades around the first national Cultural Policy Act from 1974. The study shows that ticket price levels have risen thereafter to a level much less favourable for low-income workers. Managements do use some price discrimination tactics. However, they do it uniformly for all events. They now focus on the promotion of special, ‘popular music’-based events as a response to social inclusion directives. The idea is that attending such performances will make visitors interested in the normal repertoire, as well. The choice of high-level ticket prices for the traditional content means that the standard audience remains monocultural.

Improved Method of Direct Measurement of the First-Order Mass Moments of Human Body Segments

2016 ◽  
Vol 698 ◽  
pp. 69-72
Author(s):  
Kosuke Suzuki ◽  
Kenta Nakaya ◽  
Akihiro Takita ◽  
Kazuhito Shimada ◽  
Yusaku Fujii
Keyword(s):  
Estimation Method ◽  
Previous Method ◽  
Previous Measurement ◽  
Scale Model ◽  
Measurement Time ◽  
Improved Method ◽  
First Order ◽  
Moment Estimation ◽  
Relative Standard ◽  
Mass Moment

The purpose of this research is to reduce the measurement time of the first-order mass moment estimation method proposed by us previously. In the previous method, the loads at the three points of the board are measured one by one using one piece of an expensive scale (model: GX-30KR, resolution: 0.1 g, price: 2,542 USD). The relative standard uncertainly of measurement using a rigid body is estimated to be 1.7% and the measurement time is approximately 10 minutes. In this research, three pieces of inexpensive scales (model: HD-660, resolution: 100 g, price: 17 USD) are used to reduce the measurement time. The relative standard uncertainly of measurement is estimated to be 1.9% and the measurement time is approximately 1 minute. In previous measurement, when changing the position of the scale, the position of the frame has been deviated slightly. However, in this method, this kind of error does not occur, since measurements of three points are simultaneously conducted.

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