Get the melamine foam from McMaster-Carr
. This link takes you to the site. Use the search bar and enter "melamine ceiling tile". Then scroll to the bottom of the page and you'll see "melamine foam sound absorbing ceiling tiles".
Although probably not as good as the AcoustiPack
, it is a hell of a lot more reasonable in price ($2.95 for a 24'' by 24''). It is EASY
to work with, fits exceptionally well in the recesses of the case, looks good, easily mounts with friction (no adhesive required, which also means it can be easily rearranged or removed), and does
help to absorb sound and vibrational noises.
It doesn't silence, but I think its a great modification when used with other recommendations at this site.