The use of sound intensity for characterisation of reflected energy in small rooms

Romero Perez, J

Abstract

The sound field in rooms of small dimensions used for music reproduction is
characteristically different from that found in larger rooms for music performance such as auditoria. Key differences between small critical listening spaces and large auditoria are the vastly different ranges of energy decay, 100 ms for the former and up to 8 s for the latter, and its directional behaviour, typically non-diffuse for the former and approximating a diffuse field for the latter. Despite these substantial differences, most of the metrics developed to describe the sound field in large spaces are evoked to quantify the performance of small rooms. This project focuses on developing measurement methods to characterise temporal and spatial qualities of sound in small rooms. A number of methods based on currently available acoustic probes have been developed. The implementation requisites and accuracy for each method has been quantified. Factors such as direction, time of arrival and strength of reflections have been extracted using signal analysis techniques based on the active instantaneous intensity and short-time Fourier transform. These factors are subsequently mapped to allow a description of their evolution through the energy decay in the room for a given measurement location. The best performing system, based on the use of one-dimensional p-p intensity probe mounted in a custom cradle, achieves a minimum overall mean error of 0.226 degrees and 2.971 degrees for the direct sound and first reflection respectively, which is near or below the measured human minimum audible angle (MAA). The method developed has direct applications in the quantification of small room acoustic sound fields for critical listening
purposes.

Citation

Romero Perez, J. The use of sound intensity for characterisation of reflected energy in small rooms. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Apr 30, 2014
• Publicly Available Date: Apr 30, 2014
• Related Public URLs: http://www.minalum.com.mx
• Additional Information: References : (1994). British Standards, BS EN 61043:1994 IEC 1043:1993 Electroacoustics — Instruments for the measurement of sound intensity — Measurement with pairs of pressure sensing microphones. (2002). The 3-Dimensional Acoustic Probe 3-DP. Meyer Sound Laboratories. Catalogue: Available from: http://www.microflown.com/files/media/library/Applicationnotes/meyersound_3dp.pdf [Accessed on Dec. 10th, 2012]. (2005a). Vector Intensity Probe Type 50VI. G.R.A.S. 3D PROBE. Catalogue: Available from: http://www.gras.dk/media/docs/files/items/p/d/pd_50vi_ver_06_08_02.pdf [Accessed on Oct 21th 2013]. (2005b). X-Y-Z Sound-intensity Probe Type 50VX G.R.A.S. 3D PROBE. Catalogue: Available from: http://www.gras.dk/50vx-intensity-probe.html [Accessed on May 4th 2013 ]. (2007). Data Sheet Genelec 8030A Active Monitoring System. Genelec Oy, Finland. Catalogue: Available from: http://www.genelec.com/documents/datasheets/DS8030a.pdf [Accessed on April 25th 2013]. (2008). British Standards, BS EN ISO 3382-2:2008, Acoustics — Measurement of Room Acoustic Parameters — Part 2: Reverberation Time in Ordinary Rooms. (2012). Sound Sources and Impact Sound Source for Building Acoustics: Sound Sources: OmniSourceTM Type 4295 and OmniPowerTM Type 4292-L Impact Sound Source: Tapping Machine Type 3207 Power Amplifiers Type 2734-A and 2734- B. Brüel and Kjaer. Catalogue: Available from: http://www.bksv.com/doc/bp1689.pdf [Accessed on Sep. 13th, 2012]. Abdou, A. a. M. (1994). Transient Sound Intensity Measurement for Evaluating the Spatial Information of Sound Fields in Reverberant Enclosures. Ph.D. Thesis, Concordia University, Montreal, Quebec, Canada, pp. 297. Abramowitz, M. & Stegun, I. A. (1972). Handbook of Mathematical Function with Formulas, Graphs, and Mathematical Tables, Tenth Printing, National Bureau of Standards, Applied Mathematics Series, pp. 1060, 55, p. 14, 948, 990. Ahonen, J. & Pulkki, V. (2009). Diffuseness Estimation using Temporal Variation of Intensity Vectors. IEEE Workshop on Applications of Signal Processing to Audio and Acoustics. Ahonen, J., Pulkki, V., Kuech, F., Kallinger, M. & Schultz-Amling, R. (2008). Directional Analysis of Sound Field with Linear Microphone Array and Applications in Sound Reproduction. AES 124th Convention, May 17–20, Amsterdam, The Netherlands. Alfredson, R. (1980). The Direct Measurement of Acoustic Energy in Transient Sound Fields. Journal of Sound and Vibration, 70(2), p. 181-186. Ando, Y. & Alrutz, H. (1984). Perception of Coloration in Sound Fields in Relation to the Autocorrelation Function. Journal of the Acoustical Society of America, 71(3), p. 616-618. Ballou, G. (1991). Handbook for Sound Engineers - The New Audio Cyclopedia, Third edition, U.S.A., Howard W Sams and Co, pp. 1525, p. 149, 675, 1146-1147. Barron, M. (1971). The Subjective Effects of First Reflections in Concert Halls-The Need for Lateral Reflections. Journal of Sound and Vibration, 15(4), p. 475-494. Barron, M. (1973). Growth And Decay of Sound Intensity in Rooms According to Some Formulae of Geometric Acoustics Theory. Journal of Sound and Vibration, 27(2), p. 183-196. Barron, M. (2009). Auditorium Acoustics and Architectural Design, Second, Oxon, U.K., Spon Press an Imprint of Taylor & Francis, pp. 504, p. 16, 54, 68–69,82, 84, 90, 91, 98–101, 109, 226. Barron, M. & Marshall, A. H. (1981). Spatial Impression due to Early Lateral Reflections in Concert Halls: the Derivation of a Physical Measure. Journal of Sound and Vibration, 77(2), p. 211-232. Bassuet, A. (2010). New Acoustical Parameters and Visualization Techniques to Analyze the Spatial Distribution of Sound in Music Spaces. Proceedings of the International Symposium on Room Acoustics, ISRA, August 29-31, Melbourne, Australia. Basten, T. G. H., De Bree, H. E. & Yntema, D. R. (2009). An Orientation Calibration Procedure for two Acoustic Vector Sensor Configurations. ICSV16th International Congress on Sound and Vibration, July 5-7, Kraków, Poland. Bech, S. (1995). Timbral aspects of reproduced sound in small rooms. I. Journal of the Acoustical Society of America, 97(3), p. 1717-1726. Bech, S. (1996). Timbral Aspects of Reproduced Sound in Small Rooms. II. Journal of the Acoustical Society of America, 99(6), p. 3559-3549. Begault, D. R. (2000). 3-D Sound for Virtual Reality and Multimedia NASA/TM—2000– 000000, U.S.A., National Aeronautics and Space Administration, Ames Research Center, Moffett Field, California 94035, pp. 1-246, p. Begault, D. R., Mcclain, B. U. & Anderson, M. (2004). Early reflection thresholds for anechoic and reverberant stimuli within a 3-D sound display. Proceedings of the 18th International Congress on Acoustics, Kyoto, Japan. Begault, D. R., Mcclain, B. U. & Anderson, M. R. (2001). Early reflection thresholds for virtual sound sources. Proceedings of the 2001 International Workshop on Spatial Media, Oct. 25-26, Aizu-Wakamatsu, Japan. Benjamin, E. (2010). A Soundfield Microphone using Tangential Capsules. AES 129th Convention November 4-7, San Francisco, CA, U.S.A. Beranek, L. L. (2004). Concert Halls and Opera Houses, New York U.S.A., Springer- Verlag, pp. 661, p. 524-526. Beranek, L. L. (2008). Concert Hall Acoustics—2008*. Journal of the Audio Engineering Society, 56(7/8), p. 532-544. Berens, P. (2009). CircStat: A MATLAB Toolbox for Circular Statistics. Journal of Statistical Software, 31(10), p. 1-21. Billauer, E. (2011). Peakdet: Peak detection using MATLAB [Online]. Available: http://www.billauer.co.il/peakdet.html [Accessed on 29 April 2011]. Binelli, M., Venturi, A., Amendola, A. & Farina, A. (2011). Experimental Analysis of Spatial Properties of the Sound Field Inside a Car Employing a Spherical Microphone Array. AES 130th Convention May 13-16, London, U.K., Apr 10. Blauert, J. (1997a). Spatial Hearing: The Psychophysics Of Human Sound Localization (Revised Ed'97), Cambridge, Massachusetts, U.S.A., pp. 495, p. 37-50. Blauert, J. (1997b). Spatial Hearing: The Psychophysics of Human Sound Localization (revised edition 97), Cambridge Massachussetts, MIT Press, pp. 495, p. 14, 41, 44, 49, 222, 276. Blumlein, A. D. (1933). Improvements in and Relating to Sound-Transmission, Sound- Recording and Sound-Reproducing Systems. British Patent Office. patent number No. 34,657/31. United Kingdom. Bolt, R. & Roop, R. (1950). Frequency Response Fluctuations in Rooms*. Journal of the Acoustical Society of America, 22(2), p. 280-289. Bolt, R. H. (1939). Normal Modes of Vibration in Room Acoustics: Angular Distribution Theory. Journal of the Acoustical Society of America, 11 p. 74-79. Bonsi, D., Cengarle, G. & Stanzial, D. (2007). Intensimetric Monitoring of Acoustic Quadraphonic Recordings Reproduced Through a 5.1 Loudspeaker Array. 19th International Congress on Acoustics, 2-7 September, Madrid, Spain., Jun 11. Burns, T. H. (1996). Measurement and Visualization of Instantaneous Power Flow in Steady-State Acoustic Fields. Journal of the Acoustical Society of America, 99(4), p. 2444-2445. Cavanaugh, W. J., Tocci, G. C. & Wilkes, J. A. (2009). Architectural Acoustics, N.J., U.S.A., John Wiley & Sons, pp. 352, p. 211. Cazzolato, B. (1999). Sensing Systems for Active Control of Sound Transmission into Cavities. Ph.D. Thesis, The University of Adelaide,, South Australia, Australia, pp. 451. Cazzolato, B., Halim, D., Petersen, D., Kahana, Y. & Kots, A. (2005). An Optical 3D Sound Intensity and Energy Density Probe. Proc Acoustics, November 9-11, Busselton, Western Australia. Cengarle, G. (2012). 3D audio technologies: applications to sound capture, postproduction and listener perception. Ph.D. Thesis, Pompeu Fabra University, Barcelona, Catalunya, Spain, pp. 167. Choi, C., Kim, L.-H., Doo, S., Oh, Y. & Sung, K.-M. (2001). Research on the Improvement of Naturalness in Auralization. AES 111th Convention, September 21–24, New York, N.Y., U.S.A., Aug 09. Choi, C., Kim, L.-H., Oh, Y., Doo, S. & Sung, K.-M. (2003). Measurement of Early Reflections in a Room with Five Microphone System. IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E86- A(12), p. 3283-3287. Chung, J. Y. (1978). Cross-spectral method of measuring acoustic intensity without error caused by instrument phase mismatch. Journal of the Acoustical Society of America, 64 p. 1613-1616. Cotterell, P. S. (2009). On the Theory of the Second-Order Soundfield Microphone. Ph.D. Thesis, University of Reading, United Kingdom, pp. 188. Cox, T. J., Davies, W. J. & Lam, Y. W. (1993). The Sensitivity of Listeners to Early Sound Field Changes in Auditoria. Acta Acustica united with Acustica 79(1), p. 27-41. Craven, P. & Gerzon, M. A. (1977). Coincident Microphone Simulation Covering Three Dimensional Space and Yielding Various Directional Outputs. Patent patent application 593,244. patent number 4,042,779. U.S.A. Craven, P., Law, M. & Travis, C. ( 2010). Microphone Array. Patent, patent application 12/444,628. patent number US 2010/0142732 A1 United States. D'antonio, P. & Eger, D. (1986). T/60-How Do I Measure Thee, Let Me Count the Ways. AES 81st Convention, November 12-16, Los Angeles, CA, U.S.A. Da Silva Vieira De Melo, G. (2002). Measurement and Prediction of Sound Absorption of Room Surfaces and Contents at Low Frequencies. Ph.D. Thesis, Universidade Federal De Santa Catarina, Florianópolis, Janeiro, Brasil, pp. 197. Damaske, P. & Ando, Y. (1972). Interaural Crosscorrelation for Multichannel Loudspeaker Reproduction. Acta Acoustica united with Acustica, 27(4), p. 232- 238. Daniel, J. R. M. (2003). Spatial Sound Encoding Including Near Field Effect: Introducing Distance Coding Filters and a Viable, New Ambisonic Format. AES 23rd International Conference on Signal Processing in Audio Recording and Reproduction. Davis, D. & Patronis, E. (2006). Sound System Engineering, Third edition, U.S.A., Focal Press, pp. 489, p. 131-151, 173, 175-188. De Bree, H. E. (1997). The Microflown Second Edition. Ph.D. Thesis, University of Twente, Enschede, The Netherlands, pp. 187. De Bree, H. E. (2003). An Overview of Microflown Technologies. Acta Acustica United with Acustica, 89(1), p. 163-172. De Bree, H. E., Druyvesteyn, W. F., Berenschot, E. & Elwenspoek, M. (1999). Three- Dimensional Sound Intensity Measurements using Microflown Particle Velocity Sensors. IEEE International Conference on Micro Electro Mechanical Systems, 1999. MEMS '99. Twelfth. Defrance, G., Daudet, L. & Polack, J. D. (2009). Using Matching Pursuit for Estimating Mixing Time Within Room Impulse Responses. Acta Acustica united with Acustica 95 p. 1071-1081. Del Galdo, G., Taseska, M., Thiergart, O., Ahonen, J. & Pulkki, V. (2012). The Diffuse Sound Field in Energetic Analysis. The Journal of the Acoustical Society of America, 131(3), p. 2141. Dimoulas, C., Avdelidis, K., Kalliris, G. & Papanikolaou, G. (2007). Sound Source Localization and B-format Enhancement using Soundfield Microphone Sets. AES 122nd Convention, May 5-8, Vienna, Austria. , May 11 Dimoulas, C., Kalliris, G., Avdelidis, K. & Papanikolaou, G. (2009). Improved Localization of Sound Sources Using Multi-Band Processing of Ambisonic Components. AES 126th Convention, May 7–10, Munich, Germany., Apr 03. Druyvesteyn, W. E. & De Bree, H. E. (1998). A New Sound Intensity Probe; Comparison to the Bruel & Kjaer p-p probe. AES 104th Convention 1998 May 16-19 Amsterdam, The Netherlands, p. 1-12. Elko, G. W. (1984). Frequency Domain Estimation of the Complex Acoustic Intensity and Acoustic Energy Density. Ph.D. Thesis, The Pennsylvania State University, Pennsylvania, U.S.A., pp. 376. Elko, G. W. (2000). Steerable and variable first-order differential microphone array. US Patent, patent application 08/832,553. patent number 6,041,127. U.S.A. Elko, G. W. & Pong, A. (1997). A Steerable and Variable First-Order Differential Microphone Array. International Conference on Acoustics, Speech, and Signal Processing, ICASSP-97, IEEE p. 223-226 vol. 1. Enroth, S. (2007). Spatial Impulse Response Rendering of Digital Waveguide Mesh Room Acoustic Simulations. M.Sc. Thesis, KTH University, Stockholm, Sweden, pp. 48. Essert, R. (1997). Progress in Concert Hall Design – Developing an Awareness of Spatial Sound and Learning how to Control it. EBU Technical Review (Winter), p. 31-39. Fahy, F. J. (1977). Measurement of Acoustic Intensity Using the Cross-Spectral Density of two Microphone Signals. Journal of the Acoustical Society of America, 62(4), p. 1057-1059. Fahy, F. J. (1995). Sound Intensity, Second edition, London, U.K., E & FN Spon, pp. 316, p. 2, 9, 19, 74, 85, 170, 238. Fahy, F. J. (2005). Foundations of Engineering Acoustics, London U.K., Elsevier Academic Press, pp. 465, p. 74. Faller, C. & Kolundzija, M. (2009). Design and Limitations of Non-coincidence Correction Filters for Soundfield Microphones. AES 126th Convention 2009 May 7–10 Munich, Germany. Farina, A. (2000). Simultaneous Measurement of Impulse Response and Distortion with a Swept-Sine Technique. AES 108th Convention, Feb 19-22, Paris, France. Farina, A. (2007). Advancements in Impulse Response Measurements by Sine Sweeps. AES 122nd Convention, May 5–8, Vienna, Austria. Farina, A., Amendola, A., Capra, A. & Varani, C. (2011). Spatial Analysis of Room Impulse Responses Captured with a 32-Capsules Microphone Array. AES 130th Convention May 13-16, London, U.K., Apr 10. Farina, A. & Ayalon, R. (2003). Recording Concert Hall Acoustics for Posterity. AES 24th International Conference: Multichannel Audio, The New Reality, 26-28 June, Banff, Canada. . Farina, A. & Ugolotti, E. (1998). Software Implementation of B-Format Encoding and Decoding. AES 104th Convention, May 16-19, Amsterdam, The Netherlands. Fastl, H. & Zwicker, E. (2007). Psychoacoustics Facts and Models, Third edition, New York, U.S.A., Springer-Verlag Berlin Heidelberg, pp. 470, p. 186, 196, 235, 390. Fazenda, B. M. & Romero-Perez, J. (2008). 3-Dimensional Room Impulse Response Measurements in Critical Listening Spaces. Reproduced Sound 24: Immersive Audio, Apr 30, Brighton U.K. Proceedings of the Institute of Acoustics, 30 (6). Ferguson, B. G. & Quinn, B. G. (1994). Application of The Short-Time Fourier Transform and the Wigner-Ville Distribution to the Acoustic Localization of Aircraft. Journal of the Acoustical Society of America, 96 p. 821-821. Fisher, N. I. (1971). Comment on "A Method for Estimating the Standard Deviation of Wind Directions" [Online]. Available: http://journals.ametsoc.org/doi/pdf/10.1175/1520- 0450(1983)022%3C1971%3ACOMFET%3E2.0.CO%3B2%5D. Flandrin, P., Auger, F. & Chassande-Mottin, E. (2003). Time-Frequency Reassignment— From Principles to Algorithms. Applications in Time-Frequency Signal Processing. A Papandreu-Suppappola, p. 179-203. Friedrich, R. (2012). Sound field microphone. European Patent Office, patent application 05450110.1. patent number EP 1 737 268 B1. Germany. Fukushima, Y., Suzuki, H. & Omoto, A. (2006). Visualization of Reflected Sound in Enclosed Space by Sound Intensity Measurement. Acoust. Sci. & Tech., 27(3), p. 1-3. Gade, S. (1982a). Sound Intensity ( Part 1. Theory), Brüel and Kjaer, Technical Review, Volume 3, Nærum, Denmark. Gade, S. (1982b). Sound Intensity (Part II. Instrumentation & Applications); Flutter Compensation of Tape Recorded Signals for Narrow Band Analysis, Brüel and Kjaer, Technical Review, Volume 4, Nærum, Denmark. Gade, S. (1985). Validity of Intensity Measurements in Partially Diffuse Sound Field, Brüel and Kjaer, Technical Review, Volume 4, Nærum, Denmark. Geddes, E. R. (1998). Small Room Acoustics in the Statistical Region. AES Proceedings of the 15th International Conference. Geddes, E. R. (2009). Audio Acoustics in Small Rooms Presentation Slides, GedLee LLC, [Available from: http://www.gedlee.com Access 2009]. Geddes, E. R. & Lee, L. (2003a). "Premium Home Theater: Design and Construction", Chapter 2 Hearing and Psychoacoustics [Online]. Available: http://www.gedlee.com/downloads/Chapter 2.pdf [Accessed on Nov 21th 2009]. Geddes, E. R. & Lee, L. (2003b). "Premium Home Theater: Design and Construction", Chapter 4 Room Acoustics [Online]. Available: http://www.gedlee.com/downloads/Chapter 4.pdf [Ac