Archives of Acoustics, 2, 3, pp. 177-188, 1977

Measurement of the viscoelastic constants of the cellulose used for a loudspeaker membrane and their effect upon the electro-acoustic parameters of the loudspeaker

Andrzej DOBRUCKI
Institute of Telecommunication and Acoustics of Wrocław Technical University
Poland

Czesław Adam ROSZKOWSKI
Institute of Telecommunication and Acoustics of Wrocław Technical University
Poland

The concept of a complex Young's modulus, characterizing the properties of materials with internal loss, has been introduced. The methodology of the measurement of Young's modulus and a detailed description of the method of measuring this quantity for cellulose used for a loudspeaker membrane is given. Results of measurements of the viscoelastic parameters of six kinds of cellulose are presented, and a marked influence of the absolute value of the complex Young's modulus for cellulose on the upper frequency limit of a loudspeaker with a membrane made of this cellulose is shown. Subjective investigations of loudspeakers have confirmed this conclusion.
Full Text: PDF
Copyright © Polish Academy of Sciences & Institute of Fundamental Technological Research (IPPT PAN).

References

D. R. BLAND, The theory of linear viscoelasticity, Pergamon Press, Oxford, London, New York, Paris 1960.

D. R. BLAND, E. H. LEE, Calculation of complex modulus of linear viscoelastic materials from vibrating reed measurements, Journal of Applied Physics, 26, 12, 1497-1503 (1955).

A. DOBRUCKI, Cz. A. ROSZKOWSKI, Measurement of the Young’s complex modulus of cellulose used for loudspeaker membranes, Proceedings of 23rd Open Seminar on Acoustics, Wisła 1976, p. 179.

Cz. A. ROSZKOWSKI, The influence of the material used for loudspeaker membrane upon the acoustic properties of the loudspeaker. Dissertation. Institute of Telecommunication and Acoustics, Wrocław 1976, p. 16.

Z. ŻYSZKOWSKI, A. DOBRUCKI, C. SZMAL, Studies on the relation between the synthetic index of quality and acoustic (auditory) measurements. Report No. 128/R-060/76, Institute of Telecommunication and Acoustics, Wrocław Technical University, Wrocław 1976, p. 52.