why spikes under speakers???

Blkadr...The notion that a mechanical structure (cone) can transmit vibration one way, and not the other has no basis in fact. Vibration, by its nature, is a back-and-forth motion.

Vibration of enclosure walls can be a significant sound source. It is minimized by solid construction, with internal braces, curved panels, and damping material. Except for the bottom panel of the enclosure, where the spikes/floor may serve as a brace, spikes don't help.

Suspending a speaker by ropes is the same as using spikes. You just validated my point. You are using points to keep the speaker up, just like you are when you use spikes. A cell phone is a fine example. In both situations, you have two enclosures that have moving parts inside. Whether off balance or not isn't the point. This is simple physics taught in high school. Whether the movement is significant or not, is another discussion entirely. The point is, there is movement.

S7horton...Your "simple physics taught in high school" must mean Newton's Law of Action and Reaction forces. But you evidently missed the second class where we learned how to calculate how much motion a force produces.

The suspended speaker motion test was done with a single rope, so it isn't like spikes.

Ttrhp has a good reason.

There's a second class????? It's amazing they let engineers graduate without going through the second class!

We can argue all we want, but at the end of the day, my setup sounds better with spikes.

S7horton..."Sounds better" is a perfectly good reason. You should not try to explain it further, as this will just get you into trouble.