LONG time lurker. Figured I should share this since it took me forever to find what I wanted.
I got a Roomba on Black Friday and had been looking for a long time trying to find something to keep the subs from being beat up by the Roomba. Without doing something, the Roomba would happily slide along the edge or bounce off of the speaker cover.
Everything was either ugly, not big enough, too big, too expensive, etc.
I ended up actually having a butcher block platform made to the size I wanted (24x18.75x3). I could have made it the exact size of the sub and maybe only needed 2", but I wanted a little cushion area just in case of future threats to the sub.
Just food for thought in case you're in the same boat. You could order on-line, but you may also want to check locally. Shipping was choke-worthy on these 40 pounders.
LG 55C8, Pioneer Elite VSX-LX503, Panamax M5400, Microsoft Xbox One X, Nvidia Shield Pro Definitive Technology: BP9060 Front left/right/CS9040 center/A90 front Atmos/ProMonitor 800 rear Atmos/Mirage: MX bookshelves rear left/right Rythmik FVX15