Floorstanders over Suspended Hardwood-Help Please

Audiobugged: Laminated glass (as opposed to tempered) poses no threat to kids as it is actually two layers of glass with a very resilient type of glue between the layers. It is quite thin (about 1/8" to 1/4") and will not shatter or break unless it's really subjected to violent stuff (that's why it's called security glass). It is also virtually unnoticeable, cheap, and because it's thin doesn't present problems as a result of raising the speaker too much off the floor. In this application, (carpet, suspended floor, etc) which is exactly what Mot describes, I really like it.

I had my speakers spiked through the carpet into the floors before and would never go back.

Rather than try a "band aid" that results in another set of completely different problems, why not go to the source ? If you are bothered by the bass talking to you via the floor, why not install some simple braces underneath it ? I don't see any problem with doing something like this, especially since you said it was a crawl-space and not a basement.

In order to do this and have it work properly, you will need several thick planks of wood and a few inexpensive "bottle jacks". Lay a plank down on the crawl-space floor, place a bottle jack underneath each speaker and then place another plank on top of the jacks. If you do this right, you'll not only make the floor more rigid / less susceptible to resonance, but you'll be transfering floor bounce to Earth ground via the bottle jacks.

You can take this a step further and install a few more jacks / planks where they are needed. While you or someone else is in the crawl-space, have someone walk around in that room. Where the floor makes the most noise, that's where the supports go. How many braces that you'll need will obviously depend on how sturdy the floor is.

Another less expensive alternative is to use 4 x 4 posts cut to length rather than leaving the bottle jacks in the crawl-space as the support. You may still need a jack to initially "lift" the flooring while wedging the supports in place, but you'll only need one jack to do this and you can put it to use somewhere else once you're done with it. I would suggest using a piece of wood both under and above the posts as sort of an "end cap". This will help to both level out the ground and spread the load out a bit. If you use a larger plank above the post, you may be able to contact several of the floor joists at once, which will help to make the floor more rigid. If possible, running one long plank across all of the floor joists between the speakers would work best. That is, if the speakers are running across the joists and not parallel with them.

The advantage to using the jacks is that you can adjust them as needed should the flooring, soil or house shift over time. If using posts, you may have to shim them or cut new posts. Finding just the right size shim that is both sturdy and easy to get into place might be a good trick and that's why the bottle jacks may be slightly easier ( albeit more expensive ) to work with in the long run.

While you are at it, you might want to think about breaking ground at your electrical box that houses your outlets and dropping a line straight through the floor down to a dedicated Earth ground rod. This would offer a phenomenally short and low resistance path to ground for you. Before doing so though, i would check with a local electrician to see how this could be done in order to maintain safety factors while still meeting local code. Sean
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Your #3 solution is similar to what I did with my Vienna Acoustics Mozarts on a heavily carpeted suspended wood floor with very good results although with some differences.

I placed a 1/2" piece of medium density fiberboard (MDF) - cut 3" wider in each horizontal dimension than the footprint of the speaker - on top of the carpet. Then I placed four Vibrapods on top of the MDF and a slab of 1" granite on top of the Vibrapods. On top of this sandwhich I placed the spiked speakers. They are very stable and there appears to be no interaction whatsoever between the speakers and and floor since the speakers now sound tighter and clearer than with either spikes or vibrapods alone. The Vibrapods cost $6 apiece and MDF is avaliable at Home Depot for aboout $7 for a 4'x8' sheet and they will cut it to size for you for about .50/cut. Scrap granite can be had Inexpensively - I paid $15/each.

Forget tiles or glass, etc. They are flimsy and breakable, with a relatively high resonant frequency. Get some corian (the stuff they make kitchen counters with). It's a resin product, very heavy and non-resonant. You can find it cheap at flea markets or through a plumber or contractor who cuts holes in it to fit kitchen sinks, etc.
You can have it cut to size, to fit the footprint of your speakers. Drill holes in the corian slabs and install spikes into them. Then put your spiked speakers on to the corian.
Great isolation, better sound.

If the Berber carpet is not tack-stripped to the floor, ie; area rug, I did a quick and cheap solution for my room with hardwood maple flooring. My Thiel 3.6's are 110 lbs with 3 spikes that penatrate just about anything.

For what it's worth, may not be an (AA)Audiophile Approved method but it worked in my situation which is almost identical to yours!

For a mere $10 at Lowes or Home Depot you can purchase a 4x8 sheet of 1/4" luan and have them cut it in half for you. With the 4x4 sheets I adhered low cost felt from a fabric store to the floor side and the placed the 4x4 sections under the speaker areas of the rug. Being that 1/4" is actually less than a 1/4" when it comes to wood it is not even visible from anywhere in the room. The Maple flooring is now safe from spikes and scratches from the felt backing. I've rocked and set my Thiels very hard to penatrate the carpet and it would take a 400 lb. Gorilla to push the spikes through the luan sheets.