Michi M8 clearance

Has anyone attempted with success giving less than the recommended 20" beside and above their Michi M8’s?


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.