Hi, I'm kinda new her, so I hope this is the right place to post this. English is not my native language, so you might experience some spelling error:) I am working on a project that my teacher assigned med the other day, were I am supposed to find out how i can measure the movement/velocity of a loudspeaker membran. To find the movement/velocity of the membran i believe i must fint the movement of the voice coil. (Not 100% this is the way to go) Can this be done by measuring the differrent between the current and voltage feeding the loudspeaker? Anyone have any ideas?