Time varying behavior of the loudspeaker suspension: Displacement level dependency

The compliance of the loudspeaker suspension is known to depend on the recent excitation level history. Previous investigations have shown that the electrical power as well as displacement and velocity plays a role. In this paper the hypothesis that the changes in compliance are caused mainly by how much the suspension has been stretched, i.e. the maximum displacement, is investigated.

For this purpose the changes in compliance are measured when exposing the speaker to different levels and types of electrical excitation signals, as well as mechanical excitation only. For sinusoidal excitation the change in compliance is shown to depend primarily on maximum displacement. But for square pulse excitation the duration of the excitation also plays an important role