Fujitsu MHW2040AC Product Manual page 168

Interface
*3) Automatic Acoustic Management (AAM)
The host writes to the Sector Count register with the requested acoustic
management level and executes this command with subcommand code 42h, and
then Automatic Acoustic Management is enabled. The AAM level setting is
preserved by the drive across power on, hardware and software resets.
High-speed seek to which gives priority to the performance operates as for
"Performance mode", and low-speed seek by which the seek sound is suppressed
operates as for "Acoustic mode".
Setting the seek mode by this command is applied to the seek operation in all
command processing.
5-92
AAM Level
Performance mode (Fast Seek)
Acoustic mode (Slow Seek)
Abort
Non Operate
Sector Count Register
C0h-FEh
80h-BFh
01h-7Fh
00h, FFh
C141-E258