Nice and simple. The same thing happen in my room as well. Just use Blu tack. If you are getting vibrations through the suspended floor cut a square slightly bigger then the foot print of the sub using 3/4 birch plywood (stain it) and put some blu tack in the corners and middle, stick the plywood to your wooden floor then place the sub on the plywood with the blu tack on the legs of the sub. All your problems will be fixed.