Securing Monitors to a stand

I just got done with my latest DIY project, building Speaker monitors.

They are bigger and heavier than most standard size monitors and though the stands that are used are solid and the speakers sit on them firmly, a good bump may topple them.

I am presently using Herbies Big Fat Dots under the speakers, but they don’t really anchor the speakers to the stand. Blue Tack can be used but, wouldn’t hold much. I thought of using mirror clips with padding but that would involve drilling holes in the bottom of the speakers.

Anyone have a better idea?

Thanks,

ozzy