To couple, or not to couple, that is the question


There seems to be a fundamental difference of opinion between those who would couple their speakers to the floor (e.g., with spikes), and those who would decouple them (e.g., with springs). I’ve gone both ways, but have found that I prefer the latter; I’ve currently got Sorbothane feet attached to my tower speakers, so that they wobble or "float"—much like the Townshend Platforms videos show for that similar, but more expensive, approach. My ears are the final arbiters of my listening experience, so they rule my choices. But my mind likes to have a theoretical explanation to account for my subjective preferences.

That’s where the question comes in. A very knowledgable audiophile friend insists that what I prefer is precisely the opposite of what is best: that ideally, the speaker enclosure should be as rigid and immovable as possible so that the moving cones of the drivers can both most efficiently and most accurately create a sound front free of the inevitable colorations that would come from fighting against a moving cabinet. He says that transients will be muddied by the motion of the cabinet set up by the motion of the speaker cones. And this makes perfect sense to me in terms of my physical intuitions. It’s perhaps analogous to the desirability of having a rigid frame in a high-performance vehicle, which allows the engineers to design the suspension without having to worry too much about the complex interactions with a flexing chassis.

Am I just deluded, then, in preferring a non-rigid interface between speaker and floor? Or does it depend on the kind of floor? (I get that most advice seems to favor decoupling from a suspended wood floor, and coupling to a slab; my floor is hardwood, but not exactly "suspended" as the underflooring structure is very rigid.) Or are there trade offs here, as there usually are in such options: do I gain something (but what, and how?) even as I lose something else (i.e., clean transients, especially in bass tones)?

The ears will win this contest, but I like to have my mind on board if possible. So thanks for any input you may have on this question.

128x128snilf

Snilf, you are not deluded, and your friend (and anyone else lauding coupling) is misunderstanding the big picture. Yes in theory, in the perfect world of imagination (utopia, literally “nowhere”) then being fixed and unmoving is the way to go. 
 

Only problem, we live in the real world. In the real world when the speaker cone moves one way the speaker cabinet moves the other. The result is not what the couplers would have you believe, robbing the music of dynamics and detail. The mass of the cabinet is so much greater than the moving mass of the cone and coil this might as well be zero. 

What happens instead is the vibrations from the driver propagate out from the baffle, around the sides and back, down into the floor. Vibrations never just flow like water in one direction. Agitate some water and see. Waves travel out until they hit something and reflect back. If this was just the speaker floating in space that would be the end of the story. Very quickly the cabinet (which is specifically designed to dissipate and end vibrations) would stop vibrating.

 

But the speaker is on the floor and so sets the floor to vibrating. Unlike the speakers the floor is not designed to be nonresonant. So now the floor is vibrating. The speaker is on the floor. Speaker and floor are a resonant system. Floor is connected to walls, walls to ceiling. In no time flat everything in the room is vibrating. All because you played some music. 
 

That’s with speaker coupled to floor. Speaker isolated from floor, now stops much faster. Where coupling obscures detail by getting lost in endless resonance, isolation reveals detail by reducing ringing. 
 

What you are hearing is with only a very limited and skewed form of isolation. Springs are much better. You can buy ordinary ones on Amazon for peanuts. But springs need to be tuned to the mass of the component to work well. This is a pita to find. So a better budget solution is Nobsound springs as then you adjust for load by changing the number of springs. 
 

This still leaves us with the problem of resonance. We have eliminated a lot but there’s still some because the springs aren’t damped. But too much damping and the spring reverts to something closer to sorbothane, which we don’t want. 
 

The optimal damping factor, at least according to Townshend, is only about 1%. This seemingly minuscule damping factor seems to be the main thing that accounts for the profound improvement of Pods and Podiums over Nobsound. 
 

That’s the theory. I never trust theory that much. So I tried all this stuff. All sorts of cones and spikes. Sorbothane. Ordinary springs, Nobsound, and finally Townshend. It’s not even close. 
 

But just in case you trust neither my theory nor my ears (which I always say do NOT! DYODD) then you can always check out the yt video where Max Townshend shows a seismic iPad that demonstrates visually and clearly exactly what I am talking about. 

How about for monitors on stands? Between the stand & floor or between stand & speaker?

Millercarbon! So good to have you back! 

This is sufficient "theory" to satisfy my curious mind. That is, it's a clear and reasonable explanation of how and why decoupling may work the acoustic wonders it does work, as far as my ears tell me.

In fact, it's because of your advocacy for Townshend podiums a year ago or so that I was led to try decoupling, albeit cheaply with Sorbothane. But I'm willing to believe I could improve things even more by at least going to Nobsound springs. Someday, perhaps.

Again, welcome back. We've missed your wit and wisdom on this forum.

@aewarren I tried both on basement concrete and springs sound better there too.

On a concrete basement slab, I think I would couple.