When I first bought my egg speakers they were fine but after about 6 months they started to drop downwards. I got one of my friends to get the speakers off the walls and tighten the them up but they were not as tight as when I first bought them despite him tightening them as much as he could. Now a few months later and the centre speaker keeps dropping downwards, I can twist it higher but after a while it just drops down again. Is there a way to stop them from dropping down or making them tighter to stop them from dropping down? I will have had them 2 years in Febuary.