Disk drive having an acoustic damping shield assembly with an acoustic barrier layer

A disk drive comprising:

• a) a head disk assembly (HDA) comprising
• a base having a top base surface and a bottom base surface;
• and
• a top cover secured to the top base surface;
• b) a printed circuit board assembly (PCBA) in communication with the HDA and comprising a first PCBA surface and a second PCBA surface wherein the first PCBA surface faces the bottom base surface;
• c) a bottom cover fastened to and substantially covering the bottom base surface;
• and
• d) an acoustic damping shield assembly placed between the bottom cover and the second PCBA surface, wherein the acoustic damping shield assembly comprises:
• first and second acoustic absorption layers having major surfaces;
• an acoustic barrier layer placed in between the major surfaces wherein the acoustic barrier layer is of a denser composition than each of the first and second acoustic absorption layers;
• and
• means for fixing the major surfaces and the acoustic barrier layer in a stacked relationship.