Brass footers for speakers

Coupling your speakers not only improves the bass but you'll hear a marked improvement in detail and definition.

I went a step further and replaced the four spikes with three heavy cones solidly mounted to a custom built platform. Cheap and affective.

The other POV is that "coupling" to the floor material allows sound to be conducted through the floor material to the listener, and that sound will have a different arrival time than sound conducted through air. Although concrete is less resonant than wood, it still will conduct sound.

This POV holds that "decoupling" or isolating is the way to go. Many proponents, including Genesis and NOLA speakers (the better models all have built-in decoupling), Barry Diamant, manufacturers like Stillpoints, Symposium (Rollerblocks), etc.

...just when you thought you might be getting close to being "done"...

In terms of optimum materials for cones I suggest the following ranking: NASA grade ceramics, steel and aluminum, brass and finally carbon fiber.

I use custom made stainless steel Soler Points and love them, so that's another option. They can also be had in brass but we all use the steel ones.