Sound dampening foam is ideally the last step you want to take to silencing your PC.
If your fans are loud, Then consider buying quieter ones.
no it's the ammount i have running not just one noisy fan
I doubt the number of fans makes it louder.
Ah.
Rubber washers where the fans are held?
Order of business is first to minimize amount of noise being created and blocking direct noise escape paths.
Acoustic materials can only dampen amount of reverberation and sound trying to get out through it, neither of which work if sound can leak out directly.
Which case have you got? How are your fans attached?
Is it where your rad attaches to the case? Vibrations get everywhere.
Sorry did you say 24 fans at 1200rmp
Sorry did you say 24 fans at 1200rmp
And you think foam may help? - removing half the fans would be a better option and most likely will has zero effect on your temps.
It might even be cooler with less, depending on how they are arranged.
Don't mean to be rude, but either you've been given really bad advice or it's a fan company sponsered build
so are you saying you have push pull on all three - sounds like bad advice unless you have a twin i7 server board with quad sli.