SlackBuildsOrg/system/speedcontrol

speedcontrol is a console app to change the rotation speed of
dvd-rom drives, to for example make them quieter while watching
a dvd movie.

Usage: Speedcontrol -x1 /dev/sr0

This will set the rotation speed of /dev/sr0 to 1x (-x0 will reset
to original speed). speedcontrol will only work as root, even
though it displays "OK" when run as normal user (it will simply
not work)