will my theory work?

I'm having a few issue's my extractor fan and I want to silence it or quieter it down.
I have read a few threads and a few Google sites, but I haven't found a answer to my theory.
I was thinking if i taped and cling filmed my extractor fan, placed it in a box and sealed and filled with expanding foam or even just foam sheets, the fan will be in the tent and so will the box with the other end sticking out the box pulling the air out. hope that makes sense lol
comments needed please.
Cheers in advance as normal
Peace!

i'd skip the tape and the cling film, but everything else sounds good.. see if i can find this thread for you, it should help a lot..