Real system: Electrodynamic loudspeaker driver
This video is taken during a measurement using a laser vibrometer. It represents the vibration (amplified to be visible) of a driver at a certain frequency which corresponds to two independent movements: on one hand the diaphragm, and on the other the surround suspension.
The diaphragm is light and rigid. It behaves like a rigid body.
The suspension is compliant and heavy: it flexes, and its inertia imposes a specific deformation.
The mobile part must be described by two separate masses.
