need ideas to raise speaker stands

I agree with the Granite slabs. The size you need most Tile and Marble dealers throw away. I got two with gold vein for my Silverlines and then set the spikes to where they would rest and drilled small holes for the spikes to seat(not all the way through). They look amazing and added to the low end also, but BluTak is another way to bond them. Now the stands look like a million $$, got a height, little bass to boot.

Well, David, I don't actually use the styrofoam. I have tacky stuff between my speakers and the stands. One pair is on Harbeth wooden stands, though, and I'm thinking of trying the foam on the metal stands under the others.

But, you're on point, of course. Some speakers do better with decoupling. Some, I guess, are better coupled to their stands. It makes no sense to use hard coupling to rigid high mass metal stands with lossy speaker cabinets. But right now, I am listening to a pair of old Harbeth P3's, relatively inert, not lossy, with a couple of napkins between them and the metal stands. They sound wonderful.

Roller blade wheels are great. And cheap.

Longer spikes?

Paul, you can't be into coupling, if you use that Blue Tak crap. Coupling is a physics thing. Unsound said it, even though, he jests, but if you could find three inch spikes, then you'd be coupling. Blue tak is nasty stuff. It's an isolater. It doesn't couple, but glues your speakers to the stands. NG if you're a coupler, like myself. If you're not into coupling, the sky's the limit as to how you can raise those babies. I'm of the opinion that this is not a good way to go, but rather provide your monitor speakers with stands that are coupled well to the ground and allow for your speakers to be coupled to the stands. Now we're talking. Your speakers will sing. peace, warren

I really wasn't jesting. Since spikes are used on top and below, it might be possible to buy larger replacement spikes, modify something from Home Depot or perhaps replace the spikes with large Tip Toes or the likes. Good luck. Some of the previous suggestions certainly have merit.