Try some Vibrapod cones. Relatively inexpensive, they worked well with a subwoofer on a wooden floor. They should do the trick on your desk, and they use balls, not spikes so they won't dig in.

Vibrapod Cone

Some pads would help. You may get some responses for specific products, but I would just say, in the meantime, to stick some rubber or felt "buttons" on the bottom surface of the speaker, so the speakers don't buzz on the desk. You can use 3, as a stable tripod configuration, or use 4 if you prefer.

There's debate about "coupling" vs. "decoupling" speakers to a surface. I'm skipping over that.

Auralex MoPADs are made for exactly this type of purpose, $40/pr. MoPad

While they work well, I bet any good quality dense foam would work similarly.

Quote:
I am wondering if I can do something to isolate the speakers from the desktop.

Try small pads of Blu-Tack or EZ-Tack. It was the best thing I found to interface speakers with stands, and may well work well in this application. See www.stereophile.com/features/806.

John Atkinson
Editor, Stereophile

Quote:
wondering if I can do something to isolate the speakers from the desktop.

Some setups benefit from loudspeaker isolation, but many do not. My best suggestion is to have two friends over and have them lift each speaker 1/4 inch while you listen. If you hear no change, you won't benefit from isolation.

--Ethan

I have some Auralex ProPads, they seem to work.  There are a variety of isolation products (different types of foam, rubber feet (Bright Star Isonodes)  Auralex makes MoPads and ProPads, Primeaudio makes their own similar product, Audioquest makes their sorbothane feet, etc.  If your speakers have threaded inserts, then maybe some spikes might help, but you will have to have some sort of solid base underneath that you don't mind getting damaged from the spikes.

There could be more products of various types to do this, one could buy various types of foam, sorbothane mats, etc. and make a DIY project. 

Check, places like Music Direct and other sources for what products are available.  Do an internet search for various terms like "isolation products for speakers", you might get a list of a variety of products on the market.  Townshend also makes some interesting products, but i haven't tried them.

I've seen products range from the $15 range on up.  It's what would work best to fit your budget, size/weight speaker, esthetic appeal, etc.  There's always a way to either improve the quality of sound and/or remove money from your wallet..

Good luck in your search. 

A comment on a 6-year-old post????