Adding spikes to the bottom of your speaker cabinets can be a very economical way to improve their sound by isolating them from the surface they are resting on. In my case, the floor of my apartment. This modification was done primarily for the benefit of my downstairs neighbors, because I like to play bass heavy music and getting the speakers up on spikes will reduce the amount of bass transmitted through the floor.
That's the idea, anyways.
Careful if you just have hardwood floors. If you support heavy speakers this way, they will dig right into the wood. You can be creative with protecting hardwood floors. One common method is to put pennies under the spikes. It is also common to see spike sets sold with small platforms for this purpose.
Here is a lengthy article on what may or may not happen when using speaker spikes.
noahw also has a short write up on this subject on his instructable.
Step 1: Parts List
Speaker spike sets, I got the cheapest ones I could find since I didn't pay anything for the speakers and this isn't audiophile gear.
You can get pretty fancy ones if your gear warrants.
Hammer or Allen Wrench depending on the design
Adhesive - A couple reviews at Parts Express recommended using an adhesive like Liquid Nails to improve the seal of the threaded inserts. I picked up something called Seal-All at the hardware store, but any decent glue should do the trick.
Vacuum Cleaner to suck up saw dust (for the carpeted apartment hobbyists out there).
Step 2: Measure & Drill Holes
Important: if your speakers are made out of a Press Board/MDF material that isn't a solid wood, first try a 1/16" smaller drill bit than the one recommended (It's good to try it on a scrap piece of material first, if possible). For these, I followed the advice of the reviewers on Parts Express and used a 5/16" bit instead of the 3/8" recommended. This is because MDF style material can shred up pretty easily and it helps to get a tighter fit if you use a smaller hole.
I took the time to pull out my woofer and make sure there wasn't anything that I might drill into and to judge the thickness of the material at the base of my speakers. I take no responsibility for damage to your speakers If your speakers are sealed and you can't easily see inside them to make sure you won't hit something with the drill.
Find some decent tool for making consistently spaced mounting holes, I used a square, but this isn't too crucial.
Drill down to the estimated depth of your inserts, plus a little more if you want to have your spikes go further in than your insert (again, depending on what your spike design is).
Step 3: Insert the Inserts
Apply your chosen adhesive to the outside of the Insert Nuts and slowly, carefully screw them in with the Allen Wrench so that they go in straight and even. It can be frustrating if you accidentally pull them out or push them diagonally, tearing the speaker cabinet material, so don't rush.
Step 4: Add the Spikes
If you did use some kind of adhesive to seal the nuts inside the cabinet, then give it a few hours to a day to properly dry and form a bond.
Try to keep them level and to get the tweeter as close to ear height as possible for the best sound reproduction.
Enjoy your newly floating speakers!
Don't forget to rate this instructable on the right side, there. Let me know what you think!