Hey Guys:
Thanks for the suggestion of the glue, I've done this on furniture etc. and this does it. But this won't do the trick on the speaker. They're not unscrewing they are being ripped out of the particle board, because it is a low grade of particleboard. Besides the screws may need to be removed, for service or retightened, can't do this if they're glued, in my experience, they still will pulverise the sawdust (particle board)where the glue bonds, only real fix is to thru bolt it with washer and nut or use a Tee nut... Cheers....Pose