What do you put underneath floorstanding speakers?

I have B&W cdm7nt speakers on spikes and I was wondering if there was something to put underneath the speakers to improve the sound and also possilby reduce the sound in the apartment below.
I have a wood floor with a basement underneath. I minimize floor vibrations by placing my speakers underneath a patio block that I have spray painted. I think you can use granite underneath for a more elegant solution.
to reduce the sound in the appartment bellow you should do a sound proofing.
placing a carpet in the entire room where the stereo system is located will partially solve your problem.
you may than use platforms that you would place on the carpet under the spiked speakers.
marble platforms tend to kill resonance most efficiently but are not cost efficient so you could stay with MDF ones.
Star Sound Technologies. I tried their Audiopoints first and what a differnce. The soundstage increased in height and depth. I have since then moved up the food chain and purchased their Sistrum Sp-1 to go under my speakers. I have not received them yet but I will comment when I do. They offer a 30-day money back. This has been my experience and I am sure you will get other ideas. Whatever you choose I would encourage you to hear it in your system to determine if it is a right fit.
I usually place the floor underneath 'em, keeps them from falling thru to the ground...[smirk]

My speakers are spiked & on top of 18" square 2" thick pads from your local Home Depot spray painted black. Or some store bought granite slabs for the big spender.
When I first did this there was a noticable improvement in sound.
Hey Speedball: 18" square 2" thick pads OF WHAT?

Inquiring minds want to know.

Rlwainwright, Damnit, you beat me to it.

I got hardwoor floors, i spiked my speakers and set them on top of granite slabs which rest on the floor with rubber feet.
Works pretty good for my purposes.

WIth yours i would reccommend putting a house beneath them. Best way to do it. ;)
Spikes sends the energy from the speakers right down in to the floor. A good thing - as it´s helps getting a better grip on the speaker cones. A bad thing if you have a neighbour or someone in an apartment below, as soundwaves will be picked up by the floor and carried a long way via the inner structure of the building.

You need to get rid of the energy from the speakers, but not send that of a large portion in to the floor. Some kind of soft energy-absorbent may do a better job for you. Such as rubber/vibrapod/foam cones etc. There are plenty of fish if you are willing to try such an solution. See Audiogon for ex.
If your floor is hardwood you can do one or both of the following:
1. Put small felt pads on each corner (felt is used in pianos for dampening you know)
2. Cut four small squares out of a sheet of cork (office depot etc) and place them under each corner. (cork is mostly air and is used to sound proof rooms.

Carpeting your whole room is absolutely not necessary. Granite and other rocks do not absorb or defract sound or vibrations.
the suggestion that rlwainright made works great,the pads he is talkin about are made of rubber, i use a simular product called (humane pads).

the density of the humane pads far exceeds anything you will ever get at home depot or places like that,humane's are 1" thick x 3ft x 4 ft & are coal black.

these pads are kinda pricy though at around $100 each but they work great.

For my B&W CDM 9NTs, I recently put a 1 1/2" thick soft wood plank(14"x 10"x1 1/2")not MDF, with amazing results.IMHO the improvement is dramatic with the CDM series because the spike quality is awful.You can effectively embbed the speaker in the softwood such that there is no lateral movement.Of course this home spun technology will only work for relatively lightweight speakers. The 9NTs weigh 26kgs or so, or 60 lbs.
Have a great new year.
Timken Bearings in conjunction with DH Cones sound superb

Should have checked backed sooner.

..........Pads of concrete.
Thanks Speedball! I wasn't sure what you were referring to.