the metal ball is connected to the base - so the whole thing comes off together. you need to use an allen wrench type thing and remove all the screws.
i'm sorry, but i did this a few months ago and i don't remember all the details. though i do remember that the speaker doesn't fit on the base perfectly. there were areas where i had leftover screws because i couldn't get the speaker to line up properly with the base. however, it never presented a problem.
there is a little sort of sub-base that is connected to the ball. it is not enough to simply remove those screws. you need to remove the entire base of the speaker.
i hope that helps.
yrstruly.