One of my S45-2 is breaking/jarring at high volumes. More so when playing music with high beats or bass. Only one speaker is doing this. Visibily all look ok and no holes in foam or large speaker. The sound is certainly annoying when a high volumes. Is it something easyly fixed and I am not sure how to even open the cabinet and check or look for what.

May be needs repalcement. Its powered by an MCL2P

Thanks

I wonder if the iron core in one of the coils in the cross over has loosened. (I think this model has this - the S60 certainly does) To open up to check, simply remove the front grille and undo the screws around the bass unit. All the units actually come out very easily with just a screw driver. I would check for loose bits and if nothing there, I would then consider looking at the components on the cross over board.

Opened it up to check everything and found that the metal clips which are screwed in to keep the speaker in place was loose and it was that plate which was moving at high frequecy resutling in the rattle sound.

The second speaker also had the same problem. For some reason its the lower left clip which is having issues in both speakers. The groove for the screw has lost the threads and wouldnt hold the plate or clip in tight...any resolution to this problem?

That's a common problem and it's always exactly THAT screw.
Add a drop of araldite to the screw, insert it, leave it overnight
and tighten it the next morning.
Alternatively, use a slightly larger screw.

Martin