Correction algorithm for sound scattering coefficient measurements
|
|
- Elmer Dorsey
- 5 years ago
- Views:
Transcription
1 PROCEEDINGS of the 22 nd International Congress on Acoustics Isotropy and Diffuseness in Room Acoustics: Paper ICA Correction algorithm for sound scattering coefficient measurements Monika Rychtáriková (a)(b), Nicolaas Bernardus Roozen (b), Daniel Urbán (c), Christ Glorieux (d) (a) STU Bratislava, Faculty o Civil Engineering, Dep. of Building Structures, Radlinského 11, , Bratislava, Slovakia, monika.rychtarikova@stuba.sk (b) KU Leuven, Physics and Astronomy, Soft Matter and Biophysics, Laboratory of Acoustics, Celestijnenlaan 200D, 3001 Leuven, Belgium, bert.roozen@kuleuven.be (c) A&Z Acoustics s.r.o., Repašského 2, Bratislava, Slovakia, ing.daniel.urban@gmail.com (d) KU Leuven, Physics and Astronomy, Soft Matter and Biophysics, Laboratory of Acoustics, Celestijnenlaan 200D, 3001 Leuven, Belgium, christ.glorieux@kuleuven.be Abstract Scattering coefficient measurements according to ISO are very sensitive to temperature and humidity changes in the reverberant room. Even variations as small as 0.1 K can significantly influence effective reverberation times and lead to wrong results. This phenomenon puts quite stringent limitations on how scattering measurements can be performed. This article elaborates on these limitations and discusses precautions that need to be taken in practical situations. Furthermore, we verify to what extent a stretching algorithm can help to recalibrate impulse responses and improve the quality of measured data in case measurement sequences have been subject to moderate temperature variations. Keywords: sound scattering, measurement accuracy, atmospheric conditions
2 Correction algorithm for sound scattering coefficient measurements 1 Introduction Although procedures for measurements of surface scattering coefficient have been already developed, validated and standardized [1], quite often the measurement analysis is hampered by effects of changes of the air temperature and humidity in the reverberant room, in spite of the limited time span for performing measurements is kept as prescribed by the standard (i.e., 1 hour). Changes of temperature and humidity throughout a sequence of impulse response measurements typically result in temporal deviations, apparent loss of correlation between the impulse responses, and erroneous (increased) values of the scattering coefficient obtained according to ISO Temperature changes within one hour of measurement can occur because of different reasons. Insufficient insulation of the reverberant room from the outdoor environment, e.g. when the room is not situated in the basement or not enough thermally insulated, leads to temperature drifts as soon as the building facade is exposed to changes in exposure to sunlight. The air inside the room is partially exchanged with room from outside when the door is opened, e.g. when in between measurements the room needs to be entered for checking of fixing the rotating plate. This typically goes along with a change of temperature and humidity. In case of such a situation, the question is if the whole set of measurements needs to be redone from beginning. This article introduces a stretching algorithm that can be applied to correct a measurement data set affected by temperature and humidity changes so that accurate information can be recycled. The algorithm can also be used preventively on data sets measured under strictly kept atmospheric conditions as a quality check. 2 Surface scattering coefficient 2.1 Definition The scattering coefficient s (-) is defined as the ratio between the non-specularly reflected sound energy (1 - E spec ) to the totally reflected amount of sound energy E r. Scattering by a surface of interest in a room is inducing modifications of the impulse response of that room. While bouncing back and forth between the surfaces in a room, each time waves are encountering the irregular surface, their temporal behavior is slighty scrambled. Due to the cumulative nature of this effect, the scrambling of the impulse response is exponentially increasing with time. As a result, the degree of decorrelation between impulse responses I n (t), measured under different object orientation conditions, in the typical case of a noncentrosymmetric object and room geometry is, increasing accordlingly. This results in a decrease of the slope of the logarithmic decay of the average impulse response I average (t), and thus an apparent decrease of the reverberation time and an apparent increase of the absorption coefficient as determined from the average impulse of the room, α spec. Due to the irregularity induced phase shifts of different frequency components being proportional with frequency, the apparent absorption coefficient is frequency dependent. As a consequence of the similarity between the degree of scattering on one hand and the reduction of the apparent absorption of a 2
3 room as determined from the average over rotation angle impulse responses on the other hand, the surface scattering coefficient s (-) can be estimated as αspec αs s = 1 α s (1) where α s is the average random-incidence absorption coefficient. 2.2 Measurement and simulation The surface scattering coefficient can be measured in diffuse field conditions or simulated in frequency domain by the boundary element method (BEM), in time domain by finite difference methods (FDM), or by similar algorithms. Guidelines on how to measure the random-incidence scattering coefficient is given in the standard ISO [1]. The measurement requires a random-incidence absorption coefficient measurement as described in the ISO 354 [2], followed by two extra measurements [3]. The measurement procedure is shown schematically in Figure 1. According to the norm, impulse response measurements need to be performed for different orientations of the turning table, with and without the sample (diffusor), using phase-locked averaging of samples, measured within time span one hour maximum [1]. Figure 1: Graphical description of the determination of different effective reverberation times that make part of the measurement procedure of the scattering coefficient. T 1 and T 2 are determined without, T 3 and T 4 with rotational averaging of the impulse response. T 2 and T 4 are determined with, T 1 and T 3 without sample. In order to determine the reverberation time T 4, (and the effective absorption coefficient based on the average impulse response, α 4), averaging is performed for different angles of orientation of the rotating sample table. Based on the average reverberation time T 2, the non-scattering part of the sample reflectivity and corresponding absorption α 2 is determined. Similarly, T3 and T1 are determined without sample on the baseplate. The scattering coefficient s is then calculated based on α 1,α 2,α 3 and α 4, each obtained, by means of Sabine s expression, from measured reverberation times T 1,T 2,T 3 and T 4 under the conditions described in the Figure 1. V is the room volume in m 3, S is the total area of interior surfaces in m 2, c 1,c 2,c 3, c 4 are the values of the speed of sound and m 1,m 2,m 3 and m 4 the values of the air attenuation coefficient (m -1 ) during the respective measurements. 3
4 nd 22 International Congress on Acoustics, ICA 2016 st Acoustics for the 21 Century 2.3 Influence of atmospheric conditions It is well known that atmospheric conditions have influence on sound wave propagation. Temperature and relative humidity belong to the most important factors since they directly influence the density and speed of sound of air, and its specific acoustic impedance. The impact of atmospheric conditions on sound propagation is also discussed in the international standard ISO 2533 [4]. Changes in the properties of the air have also impact on the sound amplitude, in a frequency dependent way [5,6]. Acoustic standards therefore recommend, that atmospheric conditions should be carefully noted during measurements. 3 Changes in atmospheric circumstances during ISO measurements and compensation by stretching algorithm 3.1 Standardized measurement of scattering coefficient This study is based on measurements on a real size sample, and corresponding BEM simulations. Standardized surface scattering measurements according as prescribed in ISO were performed. The experiments were done in diffuse field conditions in a reverberant room at KU Leuven, Belgium (Fig.2) with volume V = 200m3. The measurement results were compared with results of a simulation in AFMG Reflex software, which is based on the BEM. AFMG was typically used for calculation of a reflection, diffusion, and scattering of a sound wave incident onto a defined geometrical structure. Figure 2: Rotating plate without (left) and with sample (right). Figure 3 (right) shows a good fit between measured and simulated data. As the diffusor had rather small elements, scattering was only significant at higher frequencies. Figure 3 (left) shows the results of base plate measurements, as required by the ISO standard. 4
5 sca$ering*coefficient**s*(/)* random/incidence*sca$ering*coefficient* 1.00# 0.90# Base#Plate#4#measurement# 0.80# Limit#for#the#Base#Plate# 0.70# 0.60# 0.50# 0.40# 0.30# 0.20# 0.10# 0.00# 100# 125# 160# 200# 250# 315# 400# 500# 630# 800# 1000# 1250# 1600# 2000# 2500# 3150# 4000# 5000# 1/3*octave*bands***f*(Hz)* sca$ering*coefficient**s*(/)* random/incidence*sca$ering*coefficient* 1.00# 0.90# Sound#Diffusor#7#measurement# 0.80# 0.70# 0.60# 0.50# 0.40# 0.30# 0.20# 0.10# 0.00# 100# 125# 160# 200# 250# 315# 400# 500# 630# 800# 1000# 1250# 1600# 2000# 2500# 3150# 4000# 5000# 1/3*octave*bands***f*(Hz)* Figure 3: Results of base plate measurements of the scattering coefficient (left) and comparison between measured and simulated values (right). 3.2 Experiment with temperature changes during the measurement In the case of this experiment, impulse response measurements were performed on a same sample as in part 3.1. but with longer time intervals between them. In a first phase, based on impulse response measurements performed every 30 minutes (without rotating the plate), we have checked how much temperature in the room affects the data throughout a day night cycle. Figure 4 (left) shows the time shift of direct sound arrival at half day intervals, from Friday 25 September midnight till Monday noon 29 September. Figure 4 (right) depicts differences of the arriving sound reflections in the impulse response after 0.08s (about 30m of acoustic pathlength) of reverberation, i.e. after it the sound waves have reflected back and forth in the room several times. Figure 4: Illustration of differences in arrival time of the direct wave arrival signal (left) and reflected sound pressure signals after ~ 0.08s of reverberation (right) throughout a weekend, measured with half day intervals. The horizontal time axis is in units of sample periods (sampling frequency 44.1kHz). The impact of changes in air temperature and humidity on the speed of sound in the room is clearly visible. 5
6 The maximum time shift of about 2±1 sampling periods or (45±23)µs after 1342 sampling periods or 30ms in the direct signal, and 3±1 sampling periods or (68±23)µs after 5020 sampling periods or 114ms in the reflected signal fragment infers a procentual speed of sound change of respectively (0.15±0.07)% and (0.06±0.02)%. In case this change could be attributed fully to a change of temperature (the room not having been opened or entered by people during the period of measurement, humidity changes are unlikely), then it corresponds with a maximum variation in the K range. We have also performed a classical set of measurements, in the middle of which a person has entered the reverberant room for a while, introducing a change in atmospheric conditions. Interestingly, the value of the scattering coefficient, obtained in the classical way, was severely overestimating the true one. 3.3 Stretching algorithm The idea of ISO is to exploit the scattering induced decorrelation between impulse responses obtained with different orientations of the sample in order to determine the scattering coefficient. Since atmospherically induced changes of the speed of sound induce a decorrelation-like temporal compression or expansion, the method is very sensitive to such changes, overestimating the scattering coefficient. Unlike the very irregular influence of scattering, provided the temperature field in the room is uniform, the effect of speed of sound changes (c 1 c 2 ) on the impulse response for a given speed of sound c, I c (t), involves a simple, uniform, linear scaling transformation of the time axis, which can be expressed as: c = 2 Ic2() t Ic 1 t c1 (2) Provided the speed of sound ratio η=c 2 /c 1 is known, this transformation effect can be neutralized, and two impulse responses can be made to match, by applying a stretching (or compressing) transformation, with a temporal stretching factor c 1 /c 2 =1/η. In our approach, before averaging impulse responses obtained for different angles of orientation of the sample, we have chosen the first measured impulses response I c0 (t) as reference, and estimated η j =c j /c 0 by minimizing the sum of squared differences between I c0 (t) and I cj (η -1 j t). In this way, the difference between best matching impulse response I cj (η -1 j t) and I c0 (t) was only due to sample surface scattering, and not any more to differences in atmospheric conditions. After having done this stretching correction for each impulse response, the average impulse response was determined, and the ISO calculation was done. Figure 5 shows an example of an improvement of about 50% (compared to no stretching/compressing) of the match between two impulse responses when a temporal stretch factor of is applied. The remaining mismatch between the two impulse responses is due to a difference in scattering field, as a result of a difference in orientation of the sample between the two measurements. 6
7 4 Conclusions A stretching algorithm that is intended to neutralize the apparent decorrelation effect of atmospherically induced speed of sound changes on the value of the scattering coefficient as determined according to ISO was proposed and validated. Acknowledgments The authors acknowledge VEGA for grant no.1/0286/15 and H2020-MSCA-RISE-2015 for grant no PAPABUILD, and express their gratitude to Geert Dierckx for kind contributions to the measurements. References [1] ISO : Acoustics - Measurement of the sound scattering properties of surfaces, Part 1: Measurement of the random-incidence scattering coefficient in a reverberation room (2000). [2] ISO 354: Acoustics Measurement of sound absorption in a reverberation room (2003). [3] Vorländer, M.; Mommertz, E. Definition and measurement of random-incidence scattering coefficients. Applied Acoustics Vol 60 (2), 2000, pp [4] ISO 2533:1975 Standard Atmosphere [5] Bass, H. E.; Sutherland, L. C.; Zuckerwar, A. J.; Blackstock, D. T.; Hester, D. M. Atmospheric absorption of sound: Further developments. Journal of the Acoustical Society of America Vol 97 (1), 1995, pp [6] Müller-Trapet, M.; Vorländer, M. Uncertainty analysis of standardized measurements of randomincidence absorption and scattering coefficients, Journal of the Acoustical Society of America Vol 63 (1), 2015, pp [7] Mommertz, E. Determination of scattering coefficients from the reflection directivity of architectural surfaces, Appl. Acoust. 60, (2000). [8] Kosaka, Y. and Sakuma, T. Numerical study on the behavior of scattering coefficients of wall surfaces, Proc. 18th Int l Cong. Acoust. (2004). [9] Gomes, M. Vorländer M. and Gerges, S. Aspects of the sample geometry in the measurement of the random-incidence scattering coefficient, Proc. Forum Acusticum Sevilla 2002, RBA IP (2002) 7
Some issues in measurement of the random-incidence scattering coefficients in a reverberation room
Proceedings of ACOUSTICS 6 20-22 November 6, Christchurch, New Zealand Some issues in measurement of the random-incidence scattering coefficients in a reverberation room Young-Ji Choi, Dae-Up Jeong and
More informationRadiated sound power estimates of building elements by means of laser Doppler vibrometry
Radiated sound power estimates of building elements by means of laser Doppler vibrometry N.B. Roozen, L. Labelle, M. Rychtáriková,2, C. Glorieux, D. Urbán 3, P. Za tko 3, H. Mullner 4 Laboratory of Acoustics,
More informationRecent topics in acoustic scattering coefficient determination for wall surfaces
Toronto, Canada International Symposium on Room Acoustics 2013 June 9-11 Recent topics in acoustic scattering coefficient determination for wall surfaces Tetsuya Sakuma (sakuma@k.u-tokyo.ac.jp) Hyojin
More informationBasic Study on a Laboratory Measurement Method of the Normal-Incidence Scattering Coefficient
Basic Study on a Laboratory Measurement Method of the Normal-Incidence Scattering Coefficient Hyojin LEE, Tetsuya SAKUMA Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Japan. 1. Introduction
More informationInvestigations on real-scale experiments for the measurement of the ISO scattering coefficient in the reverberation room
Investigations on real-scale experiments for the measurement of the scattering coefficient in the reverberation room 43.55.BR Lieven De Geetere, Gerrit Vermeir K.U.Leuven, Laboratory for Building Physics
More informationCase studies in measurement of random incidence scattering coefficients
Case studies in measurement of random incidence scattering coefficients Michael Vorländer Institute of Technical Acoustics Aachen University (RWTH Aachen), Germany Jean-Jacques Embrechts Department of
More informationLaser scanning vibrometry measurements on a light weight building element
Laser scanning vibrometry measurements on a light weight building element N.B. Roozen, M. Rychtáriková, Katholieke Universiteit Leuven, Laboratory for Acoustics and Thermal Physics (ATF), Department of
More informationANALYSIS OF THE ACOUSTIC BEHAVIOR OF PEOPLE IN A RESTAURANT EuroRegio2016
ANALYSIS OF THE ACOUSTIC BEHAVIOR OF PEOPLE IN A RESTAURANT EuroRegio2016 Lukáš Zelem 1, Vojtech Chmelík 1, Monika Rychtáriková 1,2, Christ Glorieux 2 1 STU Bratislava, Dep. of Civil Engineering, KKPS,
More informationISSUES ON THE REVERBERATION ROOM METHOD FOR MEASURING THE SCATTERING COEFFICIENTS -BORTHER SETTING AND REVOLUTION OF TEST SAMPLE-
ISSUES ON THE REVERBERATION ROOM METHOD FOR MEASURING THE SCATTERING COEFFICIENTS -BORTHER SETTING AND REVOLUTION OF TEST SAMPLE- Hyojin LEE 1 ; Yuzo TSUCHIYA 2 ; Tetsuya SAKUMA 3 1,2,3 Graduate School
More informationTest Signal Selection for Determining the Sound Scattering Coefficient in a Reverberation Chamber
ARCHIVES OF ACOUSTICS Vol.37,No.4, pp.405 409(2012) Copyright c 2012byPAN IPPT DOI: 10.2478/v10168-012-0051-2 Test Signal Selection for Determining the Sound Scattering Coefficient in a Reverberation Chamber
More informationA suggested method to be used to measure scattering coefficients of full scale samples.
A suggested method to be used to measure scattering coefficients of full scale samples. Ronald Sauro a Michael Vargas b NWAA Labs, Inc 25132 Rye Canyon Loop Santa Clarita, CA 91355 USA ABSTRACT In attempting
More informationThe effect of an edge on the measured scattering coefficients in a reverberation chamber based on ISO
Proceedings of the International Symposium on Room Acoustics, ISRA 2010 29-31 August 2010, Melbourne, Australia The effect of an edge on the measured scattering coefficients in a reverberation chamber
More informationCOMPARISON OF THE METHODS TO CALIBRATE THE DIFFUSE FIELD SENSITIVITY OF LABORATORY STAND- ARD MICROPHONE
COMPARISON OF THE METHODS TO CALIBRATE THE DIFFUSE FIELD SENSITIVITY OF LABORATORY STAND- ARD MICROPHONE Wan-Ho Cho, Hyu-Sang Kwon, and Ji-Ho Chang Korea Research Institute of Standards and Science, Center
More informationUsing the irrotational part of the structural intensity to identify sources of vibrational energy
Sound Intensity and Inverse Methods in Acoustics: Paper ICA-8 Using the irrotational part of the structural intensity to identify sources of vibrational energy N.B. Roozen (a), C. Glorieux (a), J.-L. Guyader
More informationExperimental investigation on varied degrees of sound field diffuseness in enclosed spaces
22 nd International Congress on Acoustics ` Isotropy and Diffuseness in Room Acoustics: Paper ICA2016-551 Experimental investigation on varied degrees of sound field diffuseness in enclosed spaces Bidondo,
More informationVisualizations of sound energy across coupled rooms using a diffusion equation model
Visualizations of sound energy across coupled rooms using a diffusion equation model Yun Jing and Ning Xiang Graduate Program in Architectural Acoustics, School of Architecture, Rensselaer Polytechnic
More informationIn situ measurement methods for characterising sound diffusion
Proceedings of the International Symposium on Room Acoustics, ISRA 9 August, Melbourne, Australia In situ measurement methods for characterising sound diffusion I. Schmich (), N. Brousse () () Université
More informationCepstral Deconvolution Method for Measurement of Absorption and Scattering Coefficients of Materials
Cepstral Deconvolution Method for Measurement of Absorption and Scattering Coefficients of Materials Mehmet ÇALIŞKAN a) Middle East Technical University, Department of Mechanical Engineering, Ankara, 06800,
More informationDIFFUSIVITY AND ITS SIGNIFICANCE TO EFFECTIVE SEAT ABSORPTION IN CONCERT HALLS
akutek DIFFUSIVITY AND ITS SIGNIFICANCE TO EFFECTIVE SEAT ABSORPTION IN CONCERT HALLS M Skålevik 1,2, Bølstadtunet 7, 3430 Spikkestad, Norway 1 ) 2 ) Brekke & Strand akustikk email:msk@bs-akustikk 1 INTRODUCTION
More informationSound Field Analysis of Monumental Structures by Application of Diffusion Equation Model
Sound Field Analysis of Monumental Structures by Application of Diffusion Equation Model Zühre Sü Gül Middle East Technical University, Department of Architecture, Ankara, 06800, Turkey; MEZZO Stüdyo,
More informationProceedings of Meetings on Acoustics
Proceedings of Meetings on Acoustics Volume 19, 2013 http://acousticalsociety.org/ ICA 2013 Montreal Montreal, Canada 2-7 June 2013 Signal Processing in Acoustics Session 4aSP: Sensor Array Beamforming
More informationSummary. The basic principles of the simulation technique SERT
Determination of the absorption coefficient of structured absorbing systems in a "virtual" reverberation chamber - an application of the sound particle method SERT (Translation of the original publication:
More informationPhysics 115 Lecture 20. Reflection and Reverberation March 9, 2018
Physics 115 Lecture 20 Reflection and Reverberation March 9, 2018 1 Attenuation by absorption The wave intensity decreases due to internal friction among the molecules of the medium Attenuation is described
More informationProceedings of Meetings on Acoustics
Proceedings of Meetings on Acoustics Volume 19, 2013 http://acousticalsociety.org/ ICA 2013 Montreal Montreal, Canada 2-7 June 2013 Architectural Acoustics Session 1pAAa: Advanced Analysis of Room Acoustics:
More informationUsing an ambisonic microphone for measurement of the diffuse state in a reverberant room
Proceedings of 20 th International Congress on Acoustics, ICA 2010 23-27 August 2010, Sydney, Australia Using an ambisonic microphone for measurement of the diffuse state in a reverberant room John Bassett
More informationRoom acoustical optimization: Average values of room acoustical parameters as a function of room shape, absorption and scattering
Buenos Aires 5 to 9 September, 26 PROCEEDINGS of the 22 nd International Congress on Acoustics Architectural Acoustics for Non-Performance Spaces: Paper ICA26-56 Room acoustical optimization: Average values
More informationACOUSTIC INTRINSIC PERFORMANCES OF NOISE BARRIERS: ACCURACY OF IN SITU MEASUREMENT TECHNIQUES
Twelfth International Congress on Sound and Vibration ACOUSTIC INTRINSIC PERFORMANCES OF NOISE BARRIERS: ACCURACY OF IN SITU MEASUREMENT TECHNIQUES Francesco Asdrubali, Giulio Pispola and Francesco D Alessandro
More informationInvestigations on multi-slope sound energy decays in domed structures
Investigations on multi-slope sound energy decays in domed structures Zuhre Su Gul a) Middle East Technical University, Department of Architecture, Ankara, 06800, Turkey; MEZZO Studyo, Ankara, 06800, Turkey
More informationDELTA Test Report. DANAK TEST Reg. no Measurement of Sound Absorption Coefficient for Kvadrat Soft Cells Wall Panel Type Time
We help ideas meet the real world DELTA Test Report DANAK TEST Reg. no. 100 Measurement of Sound Absorption Coefficient for Kvadrat Soft Cells Wall Panel Type Time Client: Kvadrat Soft Cells A/S Page 1
More informationReverberation time, mean free path and sound absorption in concert halls
19 th INTERNATIONAL CONGRESS ON ACOUSTICS MADRID, -7 SEPTEMBER 007 Reverberation time, mean free path and sound absorption in concert halls PACS: 43.55.Fw, 43.55.Br Hidaka Takayuki and Nishihara Noriko
More informationBEM for the prediction of standardized scattering and diffusion coefficients of diffusers
BEM for the prediction of standardized scattering and diffusion coefficients of diffusers A. Randrianoelina a, M. Hornikx b, R. Van Luxemburg c, S. Van Eijndhoven a and A. Dastouri a a TU Eindhoven, Department
More informationODEON APPLICATION NOTE Calibration of Impulse Response Measurements
ODEON APPLICATION NOTE Calibration of Impulse Response Measurements Part 2 Free Field Method GK, CLC - May 2015 Scope In this application note we explain how to use the Free-field calibration tool in ODEON
More informationinter.noise 2000 The 29th International Congress and Exhibition on Noise Control Engineering August 2000, Nice, FRANCE
Copyright SFA - InterNoise 2000 1 inter.noise 2000 The 29th International Congress and Exhibition on Noise Control Engineering 27-30 August 2000, Nice, FRANCE I-INCE Classification: 7.2 LABORATORY MEASUREMENT
More informationNoise in enclosed spaces. Phil Joseph
Noise in enclosed spaces Phil Joseph MODES OF A CLOSED PIPE A 1 A x = 0 x = L Consider a pipe with a rigid termination at x = 0 and x = L. The particle velocity must be zero at both ends. Acoustic resonances
More informationD. BARD, J. NEGREIRA DIVISION OF ENGINEERING ACOUSTICS, LUND UNIVERSITY
Room Acoustics (2) (VTAF01) D. BARD, J. NEGREIRA DIVISION OF ENGINEERING ACOUSTICS, LUND UNIVERSITY Parameters: Importance T30, EDT: Reverberation T60 = 2*T30 D50: Clarity of speech C80: Clarity of music
More informationA numerical investigation of the sound intensity field in rooms by using diffusion theory and particle tracing
Proceedings of 20th International Congress on Acoustics, ICA 2010 23 27 August 2010, Sydney, Australia A numerical investigation of the sound intensity field in rooms by using diffusion theory and particle
More informationISO 354 INTERNATIONAL STANDARD. Acoustics Measurement of sound absorption in a reverberation room
INTERNATIONAL STANDARD ISO 354 Second edition 2003-05-15 Acoustics Measurement of sound absorption in a reverberation room Acoustique Mesurage de l'absorption acoustique en salle réverbérante Reference
More informationINFLUENCE OF TIME-VARIANCE IN AUDITORIUM ON IMPULSE RESPONSE MEASUREMENT
INFLUENCE OF TIME-VARIANCE IN AUDITORIUM ON IMPULSE RESPONSE MEASUREMENT PACS: 43.55.MC Satoh Fumiaki* 1 ; Nagayama Mitsuru* 1 ; Tachibana Hideki* 2 *1 Chiba Institution of Technology Tsudanuma 2-17-1,
More informationWitold MIKULSKI. Central Institute for Labour Protection National Research Institute Czerniakowska 16, Warszawa, Poland;
ARCHIVES OF ACOUSTICS Vol. 38, No. 2, pp. 177 183 (2013) Copyright c 2013 by PAN IPPT DOI: 10.2478/aoa-2013-0020 Method of Determining the Sound Absorbing Coefficient of Materials within the Frequency
More informationModified wave equation for modelling diffuse sound field
Challenges and Solutions in Acoustic Measurements and Design: Paper ICA2016-337 Modified wave equation for modelling diffuse sound field Hugo Dujourdy (a,b), Baptiste Pialot (b), Thomas Toulemonde (a),
More informationROOM ACOUSTICS THREE APPROACHES 1. GEOMETRIC RAY TRACING SOUND DISTRIBUTION
ROOM ACOUSTICS THREE APPROACHES 1. GEOMETRIC RAY TRACING. RESONANCE (STANDING WAVES) 3. GROWTH AND DECAY OF SOUND 1. GEOMETRIC RAY TRACING SIMPLE CONSTRUCTION OF SOUND RAYS WHICH OBEY THE LAWS OF REFLECTION
More information19 th INTERNATIONAL CONGRESS ON ACOUSTICS MADRID, 2-7 SEPTEMBER 2007
19 th INTERNATIONAL CONGRESS ON ACOUSTICS MADRID, -7 SEPTEMBER 007 Numerical simulation of low level sonic boom propagation through random inhomogeneous sound speed fields PACS: 43.8.Mw Ollivier, Sébastien
More informationFDTD analysis on the sound insulation performance of wall system with narrow gaps
FDTD analysis on the sound insulation performance of wall system with narrow gaps Takumi Asakura a Shinichi Sakamoto b Institute of Industrial Science, The University of Tokyo. Komaba 4-6-, Meguro-ku,
More informationAcoustic response in non-diffuse rooms
Acoustic response in non-diffuse rooms Jack Harvie-Clark Apex Acoustics, Gateshead, United Kingdom. Nicholas Dobinson Apex Acoustics, Gateshead, United Kingdom. Richard Hinton Apex Acoustics, Gateshead,
More informationModeling and simulation of windows with noise mitigation and natural ventilation
Modeling and simulation of windows with noise mitigation and natural ventilation Xiang YU ; Fangsen CUI ; ze-tiong TAN 2 ; Kui YAO 3 Institute of High Performance Computing, A*TAR, ingapore 2 Building
More informationTest Report. RI Acoustic Lab. Measurement of Sound Absorption Coefficient for RockDelta NoiStop Noise Barrier. 20 Feb. 07
Test Report RI Acoustic Lab Measurement of Sound Absorption Coefficient for RockDelta NoiStop Noise Barrier 20 Feb. 07 Title Measurement of Sound Absorption Coefficient for RockDelta NoiStop Noise Barrier
More informationNumerical solution to the Complex 2D Helmholtz Equation based on Finite Volume Method with Impedance Boundary Conditions
Open Phys. 016; 14:436 443 Research Article Open Access Angela Handlovičová and Izabela Riečanová* Numerical solution to the Complex D Helmholtz Equation based on Finite Volume Method with Impedance Boundary
More informationInfluence of loudspeaker directivity on the measurement uncertainty of the acoustic testing of facades.
Influence of loudspeaker directivity on the measurement uncertainty of the acoustic testing of facades. Antonio Pedrero, José Luis Sánchez, Vladimir Ulin and César Díaz ABSTRACT One of the most significant
More informationPROPAGATION, NOISE CRITERIA
2 ZVUKOVÁ INDOOR AND IZOLACE OUTDOOR V BUDOVÁCH SOUND PROPAGATION, NOISE CRITERIA kročejový zvuk Course: Building Physics AKUSTIKA V BUDOVÁCH - seminář ČKAIT (03/2017) JIŘÍ NOVÁČEK Department of Building
More informationPROPAGATION PHASE REPRESENTATION IN 3D SPACE USING POLES AND ZEROS IN COMPLEX FREQUENCY PLANE. ( address of lead author)
ICSV14 Cairns Australia 9-12 July, 2007 PROPAGATION PHASE REPRESENTATION IN 3D SPACE USING POLES AND ZEROS IN COMPLEX FREQUENCY PLANE Yoshinori Takahashi 1, Mikio Tohyama 2, and Kazunori Miyoshi 1 1 Kogakuin
More informationThe practical application of G and C 50 in classrooms
The practical application of G and C 50 in classrooms Jack Harvie-Clark 1, Nicholas Dobinson 2 1 Apex Acoustics Ltd 2 Apex Acoustics Ltd ABSTRACT Reverberation time remains the primary indicator of room
More informationON SITE DETERMINATION OF SOUND ABSORPTION COEFFICIENT OF ROAD PAVEMENTS USING MOBILE LABORATORY
ON SITE DETERMINATION OF SOUND ABSORPTION COEFFICIENT OF ROAD PAVEMENTS USING MOBILE LABORATORY Fabio Lo Castro, Sergio Iarossi, Massimiliano De Luca, Elena Ascari, Domenico Stanzial, Gaetano Licitra CNR-IDASC
More informationCalculation of the random-incidence scattering coefficients of a sine-shaped surface
Sine-shaped surface scattering calculations : Embrechts et al 1 Calculation of the random-incidence scattering coefficients of a sine-shaped surface Jean-Jacques Embrechts Department of Electrical Engineering
More informationSound-Absorbing and Insulating Enclosures for Ultrasonic Range
ARCHIVES OF ACOUSTICS Arch. Acoust., 35, 2, 157 164 (2010) DOI: 10.2478/v10168-010-0014-4 Sound-Absorbing and Insulating Enclosures for Ultrasonic Range Andrzej DOBRUCKI, Bronisław ŻÓŁTOGÓRSKI, Piotr PRUCHNICKI,
More informationModern measurement techniques in room and building acoustics
Das Messen in der Raum- und Bauakustik Michael Vorländer Institut für Technische Akustik RWTH Aachen Modern measurement techniques in room and building acoustics Introduction Modern versus classical methods
More informationCONSOLIDATED GRANULAR MEDIA FOR SOUND INSULATION: PERFORMANCE EVALUATION THROUGH DIFFERENT METHODS
Twelfth International Congress on Sound and Vibration CONSOLIDATED GRANULAR MEDIA FOR SOUND INSULATION: PERFORMANCE EVALUATION THROUGH DIFFERENT METHODS G. Pispola a and K. V. Horoshenkov b a Department
More informationAn integrated approach to Acoustics - sound propagation and the phenomena affecting it
An integrated approach to Acoustics - sound propagation and the phenomena affecting it IOA LONDON BRANCH EVENING MEETING, WSP PARSONS BRINCKERHOFF PRESENTATION BY PANOS ECONOMOU OF PEMARD, 19 TH APRIL
More informationEstimation and Determination Correction for the Area Effect of the Sound Absorber Material
Estimation and Determination Correction for the Area Effect of the Sound Absorber Material M.G. El-Shaarawy 1, Mohamed Abd-elbasseer, Abd-elfattah A. Mahmoud *, and Rabab. S. youssif 1 Faculty of Science
More informationEcophon Acoustic Calculator. Accurate values in advance
Ecophon Acoustic Calculator Accurate values in advance This publication shows products from Ecophon product range and those of other suppliers. The specifications are intended to provide a general guide
More informationEffect and minimization of errors in in-situ ground
Effect and minimization of errors in in-situ ground impedance measurements Roland Kruse, Volker Mellert Oldenburg University, Inst. of Physics, 6 Oldenburg, Germany Abstract The transfer function method
More informationThe Effect of Scenery on the Stage Acoustic Conditions in a Theatre
Department of The Built Environment Building Physics - Acoustics Research group The Effect of Scenery on the Stage Acoustic Conditions in a Theatre Master Thesis Ni Putu Amanda Nitidara Supervisors: Ir.
More informationTHE DEPENDENCE OF SOUND ABSORPTION BY AN ISOLATED ACOUSTIC RESONATOR ON THE RESONATOR S VOLUME
THE DEPENDENCE OF SOUND ABSORPTION BY AN ISOLATED ACOUSTIC RESONATOR ON THE RESONATOR S VOLUME PACS REFERENCE: 4.55.Ev Stauskis Vytautas J. Vilnius Gediminas Technical University Sauletekio al., LT-4 Vilnius.
More information1 Wind Turbine Acoustics. Wind turbines generate sound by both mechanical and aerodynamic
Wind Turbine Acoustics 1 1 Wind Turbine Acoustics Wind turbines generate sound by both mechanical and aerodynamic sources. Sound remains an important criterion used in the siting of wind farms. Sound emission
More informationMeasurement of Acoustic Properties of light weight concrete SL-Deck
DELTA Test Report TEST Reg. no. 100 Measurement of Acoustic Properties of light weight concrete SL-Deck Performed for Abeo A/S Project no.: I100486 Page 1 of 25 30 June 2014 DELTA Venlighedsvej 4 2970
More informationAcoustics Attenuation of sound during propagation outdoors Part 2: General method of calculation
ISO 9613-2 INTERNATIONAL STANDARD First edition 1996-12-15 Acoustics Attenuation of sound during propagation outdoors Part 2: General method of calculation Acoustique Attenuation du son lors de sa propagation
More informationLABORATORY MEASUREMENTS OF THE SOUND ABSORPTION COEFFICIENTS OF OSCAR EVO-PANELS
Report No. L/3237 Page 1 of 8 for Oscar Acoustics Michaels Lane Ash Kent TN15 7HT Dated: 24 July 2012 LABORATORY MEASUREMENTS OF THE SOUND ABSORPTION COEFFICIENTS OF OSCAR EVO-PANELS Report Author: M Sawyer
More informationA simple model for estimating excess attenuation of road traffic noise
A simple model for estimating excess attenuation of road traffic noise Kohei Yamamoto and Mitsuyasu Yamashita Kobayasi Institute of Physical Research, 3-20-41, Higashimotomachi, Kokubunji, 185 Japan (Received
More informationDirectional distribution of acoustic energy density incident to a surface under reverberant condition
Acoustics 8 Paris Directional distribution of acoustic energy density incident to a surface under reverberant condition C.-H. Jeong a and J.-G. Ih b a Acoustic Technology, DTU Elektro, Technical University
More information19 th INTERNATIONAL CONGRESS ON ACOUSTICS MADRID, 2-7 SEPTEMBER 2007 OPTIMAL SPACE-TIME FINITE DIFFERENCE SCHEMES FOR EXPERIMENTAL BOOTH DESIGN
19 th INTERNATIONAL CONGRESS ON ACOUSTICS MADRID, 2-7 SEPTEMBER 2007 OPTIMAL SPACE-TIME FINITE DIFFERENCE SCHEMES FOR EXPERIMENTAL BOOTH DESIGN PACS: 43.55.Ka Naka, Yusuke 1 ; Oberai, Assad A. 2 ; Shinn-Cunningham,
More informationA discussion on the uncertainty of absorption characteristics measured by ensemble averaging technique for room acoustics simulations
Challenges and Solutions in Acoustical Measurements and Design: Paper ICA2016-325 A discussion on the uncertainty of absorption characteristics measured by ensemble averaging technique for room acoustics
More informationRoom acoustic modelling techniques: A comparison of a scale model and a computer model for a new opera theatre
Proceedings of the International Symposium on Room Acoustics, ISRA 2010 29-31 August 2010, Melbourne, Australia Room acoustic modelling techniques: A comparison of a scale model and a computer model for
More informationACOUSTIC CLARITY AND AUDITORY ROOM SIZE PERCEPTION. Densil Cabrera 1. Sydney, NSW 2006, Australia
ICSV14 Cairns Australia 9-12 July, 2007 ACOUSTIC CLARITY AND AUDITORY ROOM SIZE PERCEPTION Densil Cabrera 1 1 Faculty of Architecture, Design and Planning, University of Sydney Sydney, NSW 2006, Australia
More informationThe diagram below. to the by the. outlet into. calculation. Since TRANSMISSION VIA STRUCTURE. Vibration Via Supports Duct Breakout
NOISE CONTROL IN VENTILATING SYSTEMS INTRODUCTION The diagram below shows the various noise sources and transmission paths of plant rooms and ventilation systems. For the ventilation system this can be
More informationModeling Measurement Uncertainty in Room Acoustics P. Dietrich
Modeling Measurement Uncertainty in Room Acoustics P. Dietrich This paper investigates a way of determining and modeling uncertainty contributions in measurements of room acoustic parameters, which are
More informationACOUSTIC PHENOMENA ASSOCIATED TO THE AUDIENCE
ACOUSTIC PHENOMENA ASSOCIATED TO THE AUDIENCE PACS REFERENCE: 43.55 Br Ivana Rossell, Cristina Vicent Enginyeria i Arquitectura La Salle, Universitat Ramon Llull. Pg. Bonanova, 8 (08022) Barcelona Spain
More informationAnswer - SAQ 1. The intensity, I, is given by: Back
Answer - SAQ 1 The intensity, I, is given by: Noise Control. Edited by Shahram Taherzadeh. 2014 The Open University. Published 2014 by John Wiley & Sons Ltd. 142 Answer - SAQ 2 It shows that the human
More informationTHE ACOUSTIC IMPEDANCE MEASUREMNET SYSTEM USING TWO MICROPHONES
P-7 THE ACOUSTIC IMPEDANCE MEASUREMNET SYSTEM USING TWO MICROPHONES RYU, YUNSEON BRUEL & KJAER SOUND & VIBRATION MEASUREMENT A/S SKODSBORGVEJ 307 NAERUM 2850 DENMARK TEL : +45 77 41 23 87 FAX : +45 77
More informationExperimental and numerical studies on reverberation characteristics in a rectangular room with unevenly distributed absorbers
Acoust. Sci. & Tech. 7, () PAPER Experimental and numerical studies on reverberation characteristics in a rectangular room with unevenly distributed absorbers Yosuke Yasuda ;, Ayumi Ushiyama ;y, Shinichi
More informationReverberation Impulse Response Analysis
MUS424: Signal Processing Techniques for Digital Audio Effects Handout #18 Jonathan Abel, David Berners April 27, 24 Lecture #9: April 27, 24 Lecture Notes 7 Reverberation Impulse Response Analysis 1 CCRMA
More informationON THE EFFECTS OF GROUND REFLECTION AND ATMOSPHERIC ATTENUATION ON THE NOISE OF HELICOPTERS
6th INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES ON THE EFFECTS OF GROUND REFLECTION AND ATMOSPHERIC ATTENUATION ON THE NOISE OF HELICOPTERS L. M. B. C. Campos, J. M. G. S. Oliveira CCTAE, Instituto
More informationSound, acoustics Slides based on: Rossing, The science of sound, 1990, and Pulkki, Karjalainen, Communication acoutics, 2015
Acoustics 1 Sound, acoustics Slides based on: Rossing, The science of sound, 1990, and Pulkki, Karjalainen, Communication acoutics, 2015 Contents: 1. Introduction 2. Vibrating systems 3. Waves 4. Resonance
More informationREVERBERATION TIME, STRENGTH & CLARITY IN SCHOOL HALLS: MEASUREMENTS AND MODELLING
REVERBERATION TIME, STRENGTH & CLARITY IN SCHOOL HALLS: MEASUREMENTS AND MODELLING J Harvie-Clark Apex Acoustics Ltd, Gateshead UK D Wallace Apex Acoustics Ltd, Gateshead UK N Dobinson Apex Acoustics Ltd,
More informationFESI DOCUMENT A5 Acoustics in rooms
FESI DOCUMENT A5 Acoustics in rooms FileName: A5 Acoustics in rooms - English version.pdf o o Abstract: The first theory developed was Sabine\'s formula (1902) and it is the basis of the so-called \"classic
More informationDELTA Test Report. Measurement of Sound Absorption for AqFlex ON, one Sample as a discrete Object. Performed for Flex Acoustics
DELTA Test Report TEST Reg. no. 100 Measurement of Sound Absorption for AqFlex ON, one Sample as a discrete Object Performed for Flex Acoustics Project no.: T202611 Page 1 of 7 21 January 2013 DELTA Venlighedsvej
More informationBenefits of Reduced-size Reverberation Room Testing
Benefits of Reduced-size Reverberation Room Testing Dr. Marek Kierzkowski (1), Dr. Harvey Law (2) and Jonathon Cotterill (3) (1) Acoustic Engineer, Megasorber Pty Ltd, Melbourne, Australia (2) Technical
More informationDELTA Test Report. Measurement of sound absorption coefficient for 15 mm Fraster felt Plus acoustic panels with mounting depth 45 mm
DELTA Test Report TEST Reg. no. 100 Measurement of sound absorption coefficient for 15 mm Fraster felt Plus acoustic panels with mounting depth 45 mm Performed for Fraster ApS DANAK 100/2275 Project no.:
More informationMethod of estimating the reverberant sound absorption coefficient of the absorbing structure composed of different plane porous materials
J. Acoust. Soc. Jpn. (E) 1, 1 (1980) Method of estimating the reverberant sound absorption coefficient of the absorbing structure composed of different plane porous materials Kyoji Fujiwara and Yasuo Makita
More informationAbsorption modeling with ensemble averaged impedance for wave-based room acoustics simulations
Absorption modeling with ensemble averaged impedance for wave-based room acoustics simulations Toru OTSURU 1 ; Reiji TOMIKU 1 ; Takeshi OKUZONO 2 1 Oita University, Japan 2 Kobe University, Japan ABSTRACT
More informationProceedings of Meetings on Acoustics
Proceedings of Meetings on Acoustics Volume 19, 2013 http://acousticalsociety.org/ ICA 2013 Montreal Montreal, Canada 2-7 June 2013 Architectural Acoustics Session 2aAAb: New Materials for Architectural
More informationNumber Title Year Organization Page
Id Number Title Year Organization Page 19690 S1.1 Acoustical Terminology Errata; ASA 111 R(1999) 1994 ASA 0 19691 S1.4 Specification for Sound Level Meters ASA 47-1983 1983 ASA 0 19692 S1.6 Preferred Frequencies,
More information4.2 MODELLING OF SOUND FIELDS IN ROOMS. OVERVIEW
CHAPTER 4 Room acoustics 4.1 INTRODUCTION In talking about the concept of room acoustics we shall include all aspects of the behaviour of sound in a room, covering both the physical aspects as well as
More informationProceedings of Meetings on Acoustics
Proceedings of Meetings on Acoustics Volume 9, 23 http://acousticalsociety.org/ ICA 23 Montreal Montreal, Canada 2-7 June 23 Architectural Acoustics Session aaaa: Advanced Analysis of Room Acoustics: Looking
More information19 th INTERNATIONAL CONGRESS ON ACOUSTICS MADRID, 2-7 SEPTEMBER 2007
19 th INTERNATIONAL CONGRESS ON ACOUSTICS MADRID, 2-7 SEPTEMBER 2007 FREQUENCY DEPENDENCY AND ANISOTROPY OF THE ELASTIC CONSTANTS OF (NON-)POROUS MATERIALS AND THEIR INFLUENCE ON THE USAGE IN BUILDING
More informationLast time: small acoustics
Last time: small acoustics Voice, many instruments, modeled by tubes Traveling waves in both directions yield standing waves Standing waves correspond to resonances Variations from the idealization give
More informationMeasurement of sound absorption coefficient for Fraster felt SpaceCover
DELTA Test Report TEST Reg. no. 100 Measurement of sound absorption coefficient for Fraster felt SpaceCover Performed for Fraster ApS Project no.: I100645 Page 1 of 9 27 November 2014 DELTA Venlighedsvej
More informationInfluence of Atmospheric Conditions on Sound Propagation - Mathematical Modeling
Óbuda University e-bulletin Vol. 5, No. 1, 2015 Influence of Atmospheric Conditions on Sound Propagation - Mathematical Modeling Pavol Liptai, Miroslav Badida, Katarína Lukáčová Department of Process and
More informationSITE INVESTIGATION 1
SITE INVESTIGATION 1 Definition The process of determining the layers of natural soil deposits that will underlie a proposed structure and their physical properties is generally referred to as site investigation.
More informationAPPENDIX B. Noise Primer
APPENDIX B Noise Primer NOISE PRIMER TABLE OF CONTENTS 1. INTRODUCTION...1 2. BASIC SOUND PRINCIPLES...1 2.1. SOUND AS A WAVE...1 2.2. SOUND PRESSURE LEVEL...2 2.2.1. Decibel Math...4 2.2.2. Descriptive
More information1 BAKER HOUSE DINING: LIGHTING DIAGNOSTIC
Shauna Jin + Caitlin Mueller 4.401: Lighting and Acoustics Analyses 27 April 2006 1 BAKER HOUSE DINING: LIGHTING DIAGNOSTIC 1.1 Sunlight Penetration The Baker House Dining room is exposed mostly to southern
More informationSOME OBSERVATIONS ON THE THEORETICAL PREDICTION OF STRENGTH AND CLARITY INSIDE HIGHLY DIFFUSING ROOMS
SOME OBSERVATIONS ON THE THEORETICAL PREDICTION OF STRENGTH AND CLARITY INSIDE HIGHLY DIFFUSING ROOMS PACS number: 43.55.Gx Ettore Cirillo; Francesco Martellotta Dipartimento di Fisica Tecnica Politecnico
More information