This paper investigates different techniques for modelling the non-linear parameters of the electrodynamic loudspeaker. The methods are tested not only for their accuracy within the range of original data, but also for the ability to work reasonably outside that range, and it is demonstrated that polynomial expansions are rather poor at this, whereas an inverse polynomial expansion or localized fitting functions such as the gaussian are better suited for modelling the Bl-factor and compliance. For the inductance with a pronounced asymmetric nonlinearity the sigmoid function is shown to give very good results. Finally the time varying property of the suspension is studied and it it demonstrated that a significant part of the variation can be predicted from the dissipated power.