the Townsend podiums are way better than sorbathane they isolate down to three Hertz sorbathane won't do that.
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.
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OP, the products you compare are the difference you hear in performance. Comparing methods are meaningless as only one methodology uses science by definition, and the other does not. The price points should accompany the products to help others understand your progression in vibration management. I can show you a poor performance using a spike and another that will convince you otherwise. The same goes for any vibration management part. The Audio Industry has a lot of issues when writing about vibration management. Instead of delivering education, they use methods to simplify their audience. They would rather have the public make up their language, methodologies, names for technical approaches, and beliefs.
Audio forums and video blogs continue to dispute the topics of coupling versus decoupling. In scientific facts and physics, the mechanical coupling has developed over the millennia, becoming one with the understanding of worldly functions. Mechanical coupling is well-documented and accepted by our peers. Decoupling methodologies are based on theorems or storyboarding marketers. Decoupling beliefs for audio are non-compliant with the accepted laws of motion, gravity, Coulomb’s law, and science as we know it. Techniques, opinions, or products claiming to decouple are present in the Audio Industry. A baseless opinion rendered by marketers, accessory salespeople, and audio reviewers is taking you aboard the mystical Ripley’s train.
Couple – a pair of equal and parallel forces acting in opposite directions and tending to cause rotation about an axis perpendicular to the plane containing them To mechanically ground a device: to move or transfer unwanted resonance energy out and away from the listening device or devices, forming greater efficiency in operation.
Decouple – separate, disengage, or dissociate (something) from something else To isolate or float a device, keeping the earth’s vibrations away from entering the device. Make the interaction between (electrical components) so weak that there is little transfer of energy between them, especially to remove unwanted AC distortion or oscillations in circuits with a common power supply. (Definitions from Oxford Languages)
The key words are ‘little transfer’ of energy. Resonance Energy Transfer is a geometric model using material science where resonance is transferred through high-speed conductive pathways, exiting the instrument via a mechanical ground. The ‘instrument’ can be an electronic component, loudspeaker, musical instrument, structural building, fan motor, transformer, compressor, etc. The Science-Based Reality: Again, both technically and scientifically, coupling follows the laws of motion and gravity and is supported by formulas such as Coulomb’s law and mathematics. You can do your research on decoupling to see how far you get. Our take on decoupling is slowing down the speed of resonance transfer by separating mass or altering the chemistry of the materials. In sound reproduction, everything has a timeline related to speed associated with the musical characteristics known as attack, sustain and decay. Sluggishness, slowness, and deceleration make for poor storytelling, so the term decoupling has been installed to lessen the impact of poor descriptive content. Altering the speeds of resonance transfer will change sound and musical qualities.
Designs such as ‘springs’, pucks, wafers, cones, spheres, discs, and wood blocks helped to shape and improve sonics where manufacture’s of equipment could care less. The tidal wave of shapes and sizes, various designs, and logical and ill-logical parts began in the late 80s. These designs use coupling for function and have been a part of audio reproduction for decades. Every fifteen years or so, a company figures out how to disguise or put a more techy shroud over the part and charges a lot more money for the same things we grew up using. New marketing for new products making more revenue is the result. My gripe is: A tiny fifty-cent part ($.50) has driven every couple-decouple argument throughout history. That part is called the spike. Did you ever see a three-hundred-dollar ($300.00) cone, a thousand-dollar ($1,000.00) coupling device, or a directly coupled platform compared to a spike?
Spikes rule the audiophile testing criterion and comparisons agenda. They serve the isolation and decoupling waves of innuendo. First used in the late 1960s, the sole purpose of spikes was to put airspace between a floor-borne speaker and the wood, tile, or carpeted surface. In the early days, most homes used carpeting. Along comes the nail head spike. It was the answer to most of the public objections. The cost of the part drove it home as speaker manufacturers included a set with each speaker sold. In 2021, I asked you why we are comparing a nail with a thread to that of many other expensive designs. Using spikes related to today’s modern vibration management concepts makes no sense. Are we that ignorant and refuse to move on?
Look at the house-favorite video comparison again. The nail head spike compared to a two-thousand-dollar ($2,000.00) spring-loaded stand is a marketing ploy. Are we that confused not to realize the money-making gambit? The floor-borne vibrations are only one “smaller segment” in the overall process of vibration management. Speaker movement is also minimalist to the sonic quality heard. Vibrations are part of audio reproduction, including electricity, room surfaces, equipment chassis, racking, ceiling grids, etc. Vibrational energies come from everywhere and in all directions. Vibrations and resonance build-up are continuous and located on all surfaces from the smallest transistor to the building structure. It is all going to vibrate.
Resonance is the problem.
Vibration is sound.
Why so focused on just the floors? There are airborne, electrical, electromechanical, and reflective vibrations too.
I have designed critical listening suites and recording studios and worked in theaters and arena-sized concerts. I have yet to hear smearing, speakers ringing, or sonic imperfections from adequately powered loudspeakers, so I have yet to experience ringing and do not know how that effect sounds.
Is the speaker ringing within the frequency of the human ear, or are we seeing it reproduced from manufactured energy, such as a man stomping on a floor? My focus is on the audible range of musical reproduction. I also learned through experience that most distortions begin at the source, the equipment rack, the microphone stand, manufactured force, or the musical instrument, but these distortions are always audible and not some foregone conclusion based on storyboarding. You can provide home team testing, and I will show you the flaws in the experimentation. Without independent third-party qualification and quantification, testing becomes a marketing tool. I prefer listening to exhibit A and then B rather than being shown the result on a screen.
Mechanical isolation and decoupling are myths. Only in audio are we taught, brainwashed, or advertised into believing so heavily in them. I was a victim of this philosophy for years before studying vibration and resonance. You are not alone.
Thank you for your time, Robert Sound Engineer & Vibration Management Consultant
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Hello Robert – You are correct, "decoupling" implies totally separating two systems. The proper term would probably be “damping” but this is one of those industry slang issues. Decoupling is commonly used in the soundproofing and audio products industries and has been adopted by manufacturers, industry spokespeople, and audiophiles on these forums. Damping indicates the dissipation of vibrational energy, implying some portion of the energy entering a system is absorbed and ultimately changed to another form of energy such as heat, resulting in a reduction of the vibrational energy transmitted between the two systems. This more accurately describes what happens when elastomeric materials are used between speakers and the floor. The term "isolation" is sometimes used when referring to mass-loaded spring damping systems. These types of vibration dissipation systems are prevalent in the automotive and machine industries. As with many things related to this audio hobby, decades of point-proving and arguing have not determined a clear “winner.” Audiophiles are inundated by manufacturers clamoring about how their products are “the best” and frequently using pseudo-science and marketing psychology to influence purchasing decisions. At some point, all arguing aside, it comes down to a comment I recently read on a different thread, to paraphrase, “buy and listen to what you like.” |
Damping is using a material or device to take the energy out of vibration by transferring it to heat. The shock absorber on a car forces oil or gas through small passages. That takes energy, which becomes heat, in the process damping suspension movement. Materials like sorbothane, cork, a phone book, anything like that is a form of damper. Damping only works when the two parts are coupled together. Therefore, damping is a form of coupling. The difference is when the material being coupled is rigid and inflexible we call this coupling. When the material is soft and yielding we call it damping. Either way, coupling. Decoupling, or isolation, allows the isolated component to vibrate freely on its own. Because if it touches anything the physics of mechanical vibration dictates this vibration will propagate into the adjacent material. We all know if you hit a table, the water in the glass across the other side of the table will move. There is even a famous movie where the first hint of the T Rex is the water in the glass. The glass that is in the car. The car with shock absorbers. Dampers. Coupled to the ground, car, glass, water. Even with all that earth, tires, dampers, dashboard, and glass in the way the footsteps of the dinosaur travel right on through to the water. Only slowly. The vibrations are slowed and smeared, but still there. We all know this, which is why Spielberg uses it. Damping is a form of coupling. It is damping and coupling that slows and smears. It is isolation that alleviates this. QED. |
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