Speaker vibration, Brilliant or not

[bmetro]

Hi all,

I posted about the speaker vibration from the radar arch and I think I may have a solution. I took an old speaker, put it in a baggy, flipped it upside down and sprayed the outside with low expanding foam. I then removed the speaker and presto, I have foam speaker inserts for the arch. My question now is should I go one step further and seal the foam with something, varnish etc. I havn't tried them to see if they fit in the arch, but I should be able to sand or cut them to fit.

Brilliant...or not?