Is it because of heat?
If that is the reason, can you put them on the floor?
Rotel recommends 20" beside and above for heat/ventilation I assume. I can put them on the floor, but I'd rather put them on the shelf where I only would have about 1" on each side and 9" above. I have about 4 feet behind, which is where the cooling fans are built into the amp. Also from the back, I have cooling ventilation.