should speakers be coupled or decoupled?

I have seen a bunch of threads that touch on this, but I wanted to ask the question directly: I don't understand the idea of putting ball bearing type decoupling devices underneath floorstanding speakers (with or without a platform). Doesn't this mean that the speaker will move around as it's woofer fires? And isn't that decidedly not good sonically?

I do understand the idea of having a very solid base for the speaker: either spikes down through carpet to the base material underneath, or a solid platform.

I'm very interested in people's thoughts on this matter.
Frankly, I'm skeptical about putting speakers on roller blocks or any type of decoupling device that allows for any additional movement. I think that the last thing that you want to do is allow for any z-axis (forward/backward) movement of the speaker focal node. That's got to play hell with the speakers timimg and ability to image properly.

I live in Southern California, which means slab foundations. I have always had good luck with spikes, usually with some sort of footers beneath. For bookshelf speakers or monitors I have used both Aurelex foam pads and sorbothane mats. The sorbothane is much, much better IMHO.

Good luck
Rcrerar, my comments are based on the physics of what is happening. Sometimes what people hear is based on psychology rather than physics. although science can, and does, explain psychological perceptual differences too. One of the great difficulties in perceptual psychology, and audiophilia, is that is that we don't always know when differences are physical and generalizable to all, or perceptual on an individual basis...heard only by the individual. So science rolls on, we try to learn more about the variables and their effects/interactions. In the meantime debates rage and our arguments become almost philosophical until we learn more.

I am unfamiliar with the bearing systems you describe. There is a reasonable hypothesis that could be tested though. It is possible that the bearing surface is small enough to act like a spike and minimize external vibrations from entering. Yet, the mass or design of the speaker may be enough that the speaker movements don't affect the cone movement to an audible extent. So you don't need to couple to the extent that you would with a fixed spike. However, this hypothesis should only cause the system to equal a spike's performance, not improve it.

I remain open to any scientific explanation or theory as to how this works in terms of physics. Until then, I lean towards a psychological explanation as to any perceived differences. This is equally founded in science, but it is something that may not be heard by others other than as the result of the suggestion of marketers or those looking to sell or promote the product.

In other words, I prefer Newton's Laws of Motion as an expalation as to why spikes are better than a moveable bearing in a stand. If there are other explanations, I remain open minded. But the others have the onus of proof. Until then I prefer the psychological explanation. They may be hearing differences that are real to them, maybe because they want to hear a difference or maybe because it has been suggested that a difference exists so they perceive one. This is fine, but it applies to them and it is not necessarily what you or I would perceive.

Anyway, I'm reminded of a saying that I like: "Theory and practice are the same in theory but not in practice."
It is not science to say that something does not exist until you have an explanation for it. Theory in physics is great but it is a broad extrapolation from reality, not reality itself. In any case there will be many effects that can affect the sound and theory by itself can not tell us which is the critical one. If we are not to depend on our hearing what are we to base our decisions on? Being convinced by a theory is no different than being convinced by some one else's glowing testimonials. Neither is definitive, science advances by discovering anomalous effects contrary to accepted theory.
I completely stumbled upon this. I my second system which is in my gym I have rubber floors over slab. When I placed my speakers on the spikes, the spikes went thru the rubber mat and touch the cement pad below. I think the 3/4 inch rubber floor really dampens the spikes and stops any subtle movements.It turns out to be a really nice base for speakers.
Stanwal's thought provoking post illustrates how observed "facts" can lead to philosophical arguments. When facts don't fit theory, or other facts, we use philosophy to reform arguments and assist in the development of new theory that better fits the facts. I put "facts" in quotes above because it is always an open question with the human variable as to whether the "facts" are, in fact, "facts" at all, other than to the person making the claim.

So, is it a "fact" that putting speakers on moveable bearings improves sound? If this fact can't be proven objectively or demonstrated to another person, then maybe it isn't a "fact" at all. Maybe it's just an opinion, and as such, only a fact to that person.

It is an observed "fact", and consistent with "theory", that the earth is round. So somebody looks out the window in Kansas and says: "My goodness, look at that, the earth is flat! That theory and those other observations about the earth being round must be incorrect. My friends here who are looking out of the window with me all agree. The earth is flat! We will have to change the theory that the earth is round to accommodate the observations that I and my friends have made about the earth actually being flat."

Anything wrong with this argument? No...Yes...???

Here's an analogy.

It is an observed "fact", and consistent with "theory", that putting speakers on spikes will improve performance. One of the theoretical bases for this is Newton's Laws of Motion. So somebody in Kansas puts their speakers on a moveable bearing and says: "My goodness, this sounds better! That theory and those other observations about fixed spikes must be incorrect. My friends here who are listening with me all agree! We will have to change the theory that the use of fixed spikes on speakers is based upon to accommodate the observations that I and my friends have made."

So, if you think moveable speaker stands improve performance, let's hear the theory upon which this is based so we can test it. If you don't have a theory, all you have is an opinion. And I prefer my opinion over yours. You see....I don't live in Kansas.