I have just built some sand filled speaker stands following these plans instructions. The build was quite easy and they are really sturdy but I'm a little confused about some things. First I have some auralex mopad’s that my monitors were sitting on before, should I use these in conjunction with the stands or just place the speakers directly onto the stand? Also the designer mentioned that he installed carpet spikes for isolation rather than decoupling. I have hardwood floors and would like to come up with a better solution.
Thanks for your help,
Terry

The best place for specific information, is to first try the manufacturer of your speakers. The next would be specialist hifi forums, with people who have, or have had, the same speaker. Different speakers response to different methods of support is extremely varied. Some speakers require an open, light weight support, and others, which I hope yours are, require mass and weight. There are many speakers that use loose coupling to the floor, using things like Totems claw, sitting on wood blocks, with no spikes, wooden cones, etc. The other interface to consider, is the coupling of the speaker to the stand. Some use cones, spikes, bluetack, so check that out as well.
Try to get specific information for your speakers.
Good luck.

Spikes are a form of decoupling, in that it minimizes the surface area of the coupling between the stand and the floor.

I'd use some decoupling method somewhere, the mopads are good (or a simple piece of 1" 705 rigid fiberglass). Spikes work too, but don't scratch your floor.

I disagree with the previous poster; I don't know of any speaker that won't benefit from being decoupled from the floor.

The fun part is getting rid of the vibrations from the speaker cabinet, without allowing any of the other vibrations from the stand / floor back into the speaker which produce a whole set of other colourations. Good 'decoupling' helps - but be aware that spikes pressed to hard into a wooden floor actually couple it to the floor and can then transmit floor vibrations back into the speaker via the spike. A good compromise here is to use spike protectors on a wooden floor (simple small coins will do the job)
My favourite method of putting a speaker on a stand is to use 800 grit 'wet & dry' paper onto the stand top, then sitting the speaker directly onto that. The main de-coupling then occurs via the spikes in the bottom of the stand.
But this is specialist stuff for a HiFi forum I guess.
Have fun - great results can be had!