Heavy Speakers with Spikes on a Concrete Floor

I don't know why you would need a 4" platform and 3" spikes. If you are right on the concrete, find some short cones or spikes with a wide base and place them under your speakers. If you are on carpeting over concrete, you'll need something just long enough to penetrate the carpet and elevate the speakers above the carpet.

However, you may need a spiked platform unless you want to install the spikes in the bottom of your speakers.

If the speakers are too heavy for one person to lift, have two people lift the cabinet while a third puts the platform in position.

I have a ceramic tile floor and I use carriage bolts, with the convex side to the floor, to great effect. My speakers are VSA SR IV's, at about 140 pounds each. Less than $5 at Home Depot. The bolts that is ;-)

Thanks for the replies. Yes the concrete floor is carpeted but no padding.
I own the Andra 2 speakers. They have some pretty substantial steel spikes that lift the speaker about 3 inches from the floor.
I also have some custom made brass Audio points for them, but I think the spikes that came with them work the best.

Still, I wonder if there is any reason to think that the speakers would sound better on a Maple platform.

Has anyone tried this?

Yes, I did. Pierre is a friend of mine and often has good ideas but this is not one of them. I tried one of his large $600 platforms that tilted the speaker upward and sat almost on the floor. Sounded VERY strange. I sold it to someone else who mounted floor standing speakers on it, not using the tilt feature. He had it for sale on Audiogon in a short time. I like the way my speakers sound on concrete [with thin rug]. I can't imagine how it would produce the kind of sound he describes. I had some boomy bass with WAY too much treble, but that was room reflection problems I cured with Ready Acoustics panels. I have had very good luck with Star Sound Audio Points but if what you have is working leave it alone.