Modeling Viscoelastic Properties of Loudspeaker Suspensions Using Fractional Derivatives

A lot of materials used in loudspeaker susperisions exhibit significant frequency dependence of damping and compliance due to their various viscoelastic properties. Few empirical models have been proposed to take into account these variations, the most used one is the LOG model proposed by Knudsen and Jensen. On the other hand, the fractional calculus has been successfully applied to characterize the rheological properties of viscoelastic materials including their frequency dependence. This study shows that the loudspeaker suspension can be succesfully modeled using fractional derivatives. The traditional low-frequency loudspeaker model is extended by a simple fractional element. It is shown on four loudspeakers with different types of suspension with different properties that the proposed model fits well with all the studied cases.