An ironless large displacement flat piston loudspeaker

• Autorzy: Remy M. , Lemarquand G. , Guyader G.
• Języki publikacji: EN

Abstrakty

EN

This paper presents a small wide-band loudspeaker. Particular efforts have been made to reduce the nonlinearities of the loudspeaker as much as possible. The motor structure is completely ironless, the elastomer suspensions are replaced by ferrofluid seals and a monobloc carbon foam piston substitutes the traditional conic membrane. The circular radiating surface, which is flat, has a diameter equal to only 2 cm. Therefore, in order to obtain a sufficient sound pressure level at low frequencies, large displacements of the piston are necessary. After a detailed description of each part of the loudspeaker, theoretical results of the expected performances of this transducer are given.

Słowa kluczowe

EN

loudspeaker; ironless; flat piston; large displacement

• Wydawca: Instytut Podstawowych Problemów Techniki PAN ; Komitet Akustyki PAN ; Polskie Towarzystwo Akustyczne
• Czasopismo: Archives of Acoustics
• Rocznik: 2009
• Tom: Vol. 34, No. 4
• Strony: 591--599
• Opis fizyczny: Bibliogr. 20 poz., wykr.

Twórcy

autor

Remy M.

autor

Lemarquand G.

autor

Guyader G.

• LAUM, CNRS, Université du Maine Av. O. Messiaen, 72085 Le Mans Cedex 9, France

Bibliografia

• [1] Gander M.R., Moving-coil loudspeaker topology as an indicator of linear excursion capability, JAES, January, 29, 10-26 (1981).
• [2] Vanderkooy J., A Model of Loudspeaker Driver Impedance Incorporating Eddy Currents in the Pole Structure, JAES, March, 37 (1989).
• [3] Klippel W., Loudspeaker Non Linearities - Symptoms, Parameters, Causes, presented at the AES 119th Convention, New York, USA, 2005.
• [4] Ravaud R. et al., Time-varying non linear modeling of electrodynamic loudspeakers, J. of Applied Acoustics, 70, 3, 450-458 (2009). doi:10.1016/j.apacoust.2008.05.009
• [5] Berkouk M. et al., Analytical calculation of ironless loudspeaker motors, IEEE Trans. Mag., 37, 2, 1011-1014 (2001). doi:10.1109/20.917185
• [6] Lemarquand G., Ironless Loudspeakers, IEEE Trans. Mag., 43, 8, 3371-3374 (2007). doi:10.1109/TMAG.2007.897739
• [7] Ohashi Y., Magnetic Circuit and Speaker, Patent EP 1 553 802 A2, 2005.
• [8] House W., Transducer Motor Assembly, US Patent 5,142,260, 1992.
• [9] Remy M. et al., Ironless and leakage free voice-coil motor made of bonded magnets, IEEE Trans. Mag., 44, 11, 4289-4292 (2008). doi:10.1109/TMAG.2008.2003401
• [10] Merit B. et al., In Pursuit of Increasingly Linear Loudspeaker Motors, IEEE Trans. Mag., 45, 6, 2867-2870 (2009). doi:10.1109/TMAG.2009.2018780
• [11] Quaegebeur N. et al., Transient modal radiation of axisymmetric sources: Application to loudspeakers, J. of Applied Acoustics, doi:10.1016/j.apacoust.2009.10.003
• [12] Jibin Z., Jiming Z., Jianhui H., Design and pressure control of high-pressure differential magnetic fluid seals, IEEE Trans. Mag., 39, 5 part 2 2651-2653. doi:10.1109/TMAG.2003.815543
• [13] Rosensweig R.E. et al., Study of audio speakers containing ferrofluid, J. Phys.: Condensed Matter, 20, 20, 204147 (2008). doi:10.1088/0953-8984/20/20/204147
• [14] Ravaud R. et al., Mechanical Properties of Ferrofluid Applications: Centering Effect and Capacity of a Seal, Tribology International, 43, 1-2, 76-82 (2009). doi:10.1016/j.triboint.2009.04.050
• [15] Ravaud R., Lemarquand G., Modeling an ironless loudspeaker by using three dimensional analytical approaches, PIER, 91, 53-68 (2009). doi:10.2528/PIER09021104
• [16] Ravaud R. et al., Magnetic pressure and shape of ferrofluid seals in cylindrical structures, J. Appl. Phys., 106, 3, 34911 (2009). doi:10.1063/1.3187560
• [17] Ravaud R., Lemarquand G., Design of ironless loudspeakers with ferrofluid seals: Analytical study based on the coulombian model, PIER B 14, 285-309 (2009). doi:10.2528/PIERB09031904
• [18] Ravaud R. et al., Discussion about the analytical calculation of the magnetic field created by permanent magnets, Progress In Electromagnetics Research, PIER B 11, pp. 281-297, 2009. doi:10.2528/PIERB08112102
• [19] Ravaud R. et al., The three exact components of the magnetic field created by a radially magnetized tile permanent magnet, PIER 88, pp. 307-319, 2008. doi:10.2528/PIER08112708
• [20] Brooks M., Turner H.M., Inductance of coils, University of Illinois Engineering Experiment Station Bulletin, no. 53, 1912.