Application of BEM to modelling loudspeaker's directivity patterns based on its dynamic behaviour

• Autorzy: Skrodzka E. , Sęk A.
• Języki publikacji: EN

Abstrakty

EN

This paper is concerned with numerical modelling of directivity patterns of loudspeakers. The Boundary Element Method (BEM) was used. Results of modal analysis served as the boundary conditions for modelling. For a loudspeaker with a planar membrane and a woofer with a quasi-conical paper membrane, the directivity patterns found during modelling were compared to characteristics measured in an anechoic chamber. It was shown that the calculated patterns were similar to those measured in the chamber. In particular, the position of an acoustic axis and value of sound pressure level along the main axis of symmetry was predicted with satisfactory precision. Thus, the relation between vibration and radiation of the loudspeakers was shown.

• Wydawca: Instytut Podstawowych Problemów Techniki PAN ; Polska Akademia Nauk
• Czasopismo: Archives of Acoustics
• Rocznik: 2001
• Tom: Vol. 26, no. 2
• Strony: 75--91

Twórcy

autor

Skrodzka E.

• A. Mickiewicz University, Institute of Acoustics

autor

Sęk A.

• A. Mickiewicz University, Institute of Acoustics

Bibliografia

• 1] C.K. Amedin, Y. Champoux and A. Berry, Acoustical characterization of absorbing porous materials through transmission measurements in free eld, J.A.S.A., 102, 4, 1982 1994 (1997).
• [2] C. de Boor, A practical guide to splines, Springer-Verlag, N.Y., Berlin 1978.
• [3] A. Bra«ski, Problem of an optimal discretization in acoustic modelling, Archives of Acoustics,
• 23, 2, 239 249 (1998).
• [4] A. Bra«ski, Smooth model of an acoustic source, Engineering Analysis with Boundary Elements, 22, 333 340 (1998).
• [5] C.A. Brebbia and J. Dominguez, Boundary elements, An introductory course, Comp. Mech. Publ., McGraw-Hill Book Company, Southampton 1992.
• [6] S.N. Chandler-Wilde and D.C. Hothersall, E cient calculation of the Green function for acoustic propagation above a homogeneous impedance plane, J.S.V., 180, 5, 705 724 (1995).
• [7] J.S.R. Chisholm and R.M. Morris, Mathematical methods in physics, North-Holland Publishing Company, Amsterdam 1966.
• [8] R.D. Ciskowski and C.A. Brebbia, Boundary element methods in acoustics, Comp. Mech. Publ., McGraw-Hill Book Company, Southampton 1991.
• [9] M.E. Delany and E.N. Bazley, Acoustical properties of brous absorbent materials, Appl. Acoustics, 3, 105 116 (1970).
• [10] L. Demkowicz, Adaptative nite elements methods [in Polish], The Cracow University of Technology, Monography 46, Cracow 1986.
• [11] L. Demkowicz, A. Karafiat and J.T. Oden, Solution of elastic scattering problems in linear acoustics using h−p boundary element method, Comput. Methods Appl. Mech. Eng., 101, 251 282 (1992).
• [12] D. Duhamel and P. Sergent, Sound propagation over noise barriers with absorbing ground, J.S.V., 218, 5, 799 823 (1998).
• [13] Z. Engel et al., Acoustic barriers [in Polish], University of Mining and Metallurgy, Cracow 1990.
• [14] Z. Engel and S. Zaremba, Analysis of acoustic barriers [in Polish], Mechanics, 10, 4, 9 29 (1991).
• [15] O. von Estorff, Boundary elements in acoustics, Comp. Mech. Publ., Southampton 2000.
• [16] J.J. Grannell, A hierarchic p-version boundary-element method for axisymmetric acoustic scattering and radiation, J.A.S.A., 95, 5, 2320 2329 (1994).
• [17] D.C. Hothersall, K.V. Horoshenkov, P.A. Morgan and M.J. Swift, Scale modelling of railway noise barriers, J.S.V., 234, 2, 207 223 (2000).
• [18] W.S. Hwang, Hypersingular boundary integral equations for exterior acoustic problems, J.A.S.A.,
• 101, 6, 3336 3342 (1997).
• [19] T. Isei, T.F.W. Embleton and J.E. Piercy, Noise reduction by barriers on nite impedance ground, J.A.S.A., 67, 1, 46 58 (1980).
• [20] P. Jean and Y. Gabillet, Using a boundary element approach to stady small screens close to rails, J.S.V., 231, 3, 673 679 (2000)