LD Systems DAVE 8 XS G grille de protection noire pour haut-parleur
Mine fell off within 4 days. The adhesive which attaches the material part of the hook + loop fasteners to either the speaker or grille, is simply not strong enough, and it is the fastener that fails.
The grilles are obviously an afterthought and not something that was considered during the main design process of the speakers. The grilles themselves are made well enough, and the design and quality is matching of the speakers. It really is just the attachment method that is not optimum.
Some alternatives would be magnets, although this would require screwing into the grille and speakers - not optimum. Depending on whether you wish to remove the grilles in future or not, a better option might be a stronger adhesive tape such as 3M VHB foam tape, or an acrylic tape. I might go down this route with them as don't see much need to take the grilles off in future (although the speakers do look better without the grilles IMHO).