Suspended Floor and Speaker Isolation

[tyefighter]

Hi guys Im after some advise if i may

My system is as listed in my signature, setup in my bedroom which is about 12ft square. The room has the usual bedroom stuff. large double bed etc. and a solid real wood suspended floor. It sounds good at low nighttime listening (circa 55) but when i crank it up it gets confused and boomy which obviously im not really enjoying 

I assume its down to the room not being ideal and the speakers being restricted to only about 10 inches away from the rear wall. I intend to get John Smiths - Get Better Sound book to learn more on positioning and room treatment. However I had an idea that the wooden floor maybe acting as a huge speaker and creating a lot of the boom. 

There is a thread about Townsends bars http://devialetchat.com/showthread.php?t...=isolation
These would isolate my speakers from the floor however they would be quite the mismatch with my rather modestly priced speakers

So my question is am I correct in thinking that the floor is negatively effecting my sound and if so is there some DIY isolation ideas i could try?
I was thinking maybe some granite slabs or two granite slabs stacked and separated by a rubber mat to assist in the isolation?  I dunno what do you guys think?

Currently my speakers have spikes resting on spike cups and have an internal compartment where they can be filled to add to their weight if you think that may be beneficial

thanks in advance 
Gordy