In article ,
says...

I'm definitely no expert but am just finishing off a pair of hefty DIY
floorstanders. They are on stands that are basically MDF boxes filled with
building sand....just an idea you might consider for home made stands. A bit
easier than half a ton of paving slabs :-)

Also, if the problem you have is with limited treble dispersion then you
might consider angling your floorstanders up slightly.

Or sitting closer to the floor !

T.