A disc drive assembly is provided including a head disc assembly, a
housing having a base and a cover cooperating with one another to form a
chamber in which the head disc assembly is housed, and a damper structure
in operative association with the housing for dampening noise and/or
vibration emanated from the head disc assembly. The damper structure
includes a viscoelastic damper layer and a continuous, polymeric
constraining layer intimately contacting and encasing the viscoelastic
damper layer. The constraining layer has a greater stiffness and higher
modulus of dynamic shearing elasticity than the viscoelastic damper
layer, and is molded from a high density filler and a moldable compound
that is immiscible with the viscoelastic damper layer to provide a
discrete interface between the constraining layer and the viscoelastic
damper layer.