As long as the wooden blocks are covered with carpet, they should work fine-ish.
The idea is to de-couple the speaker from the hard floor surface.
To do this, you would:
A) Rise the speaker off of the floor, giving the sound more room before deflecting off of the floor.
2) Use a dampener such as carpeted wood, or any manufactured dampening material.
III) Mount the speaker on legs, such as small table legs available at any home improvement store.
The reason to de-couple is to stop the speaker cabinet from interacting with the hard floor.
I know that I have seen threads where people have made there own, using 1x1's, plywood, and carpet remnants.
Alternatively, some people just use small carpets under their speakers.
I currently, have been unable to locate any of these threads, but I know I have seen them somewhere, either here or over at Bluray.com.
Maybe someone else can link to them and/or provide pix.
To the OP, are you experiencing sound issues? What prompted your inquiry?