[SoundStage!]Max dB with Doug Blackburn
Back Issue Article

July 2002

Exploding the Myth of the Cone Footer

Cone feet have achieved a mystical presence in high-end audio, mostly because high-end audiophiles accept plausible-sounding technical explanations and love amazing concepts like "mechanical diode" and "decoupler." I just read some more silliness about cones in one of those dirty print magazines (as opposed to a nice, clean online magazine like SoundStage!), so you get the benefit of my latest need to vent on the subject of cone as high-end-audio footer. I’ve touched on the subject before, but it’s time to put all the issues in one place.

Here’s why a cone is neither a mechanical diode nor any kind of decoupler. The problem with vibrations that affect audio systems is that they are small and you can’t see them. But here’s a news flash: large vibrations and small vibrations follow the same physical laws. Small vibrations you can’t see do not behave in some special way that allows an object like a cone to affect the vibrations.

Let’s make the vibrations larger so you can see or feel what's happening -- remembering that small and large vibrations follow the same physical rules. Take an old variable-speed blender and hang a weight on one of the choppers so that the thing vibrates like crazy when the motor runs. Attach this to the bottom of one of your component shelves. On the shelf is an audio component of your choice sitting on your favorite cone footers. Turn the motor on and see what happens. Awww, after just a few seconds, the component danced over the cones and fell off of them. How could that happen? Are the cones acting as ANY KIND of mechanical diode? No. Are those cones decoupling the component from the vibrating blender motor in ANY way? No. Change the frequency of the vibrations by changing the blender’s motor speed. Any difference? No -- pretty much the same result.

If you attach the cone footers to the component so that it can’t fall off the cones, you can feel the resonances from the blender motor in the component, and the only way the resonances get into the component is through the cones. It should be apparent that any frequency that moves the component shelf up and down will also cause the cone to also move up and down, and that motion, obviously, will be transmitted to the component. Likewise, any motion of the shelf that is in the front-back or left-right plane will move the cone left-right or front-back as well. It has to. You have all the weight of the component resting on three tiny cone points that are digging into the shelf a little bit. If the shelf moves left-right, front-back, or up-down, the cone is going to move also. If the cone moves, it transmits resonances to the component. Nothing else can happen.

Now this is an important concept: vibrations are physical. In the case of the types of vibrations we are talking about in audio systems, the resonances involve the motion of relatively solid materials -- metal, wood, and wood products like MDF mostly. Every resonance can be characterized by the amount of motion and the frequency of the motion in the three dimensions of up-down, left-right and front-back. Whatever the cone "sees," it transmits. Replace the cone with a cylinder and you get the same effect. Replace the cone with a cube -- same effect. But each shape will have a different contact patch, either at the component end, at the shelf end or both. That contact patch will affect what gets transmitted back and forth. The large surface area will collect small resonances over a large surface with lighter contact. The point will collect resonances over a small surface, but it will be tightly coupled to the shelf surface. The point will be subjected only to whatever resonances exist in the shelf at that point rather than to the resonances that exist over a larger surface area, which get averaged out by the larger surface area contact. So yes, cones will sound different than cylinders or cubes. Cones even sound different depending on whether you use them points up or points down, but the difference in sound is not necessarily better than some other shape, just different.

If cones decoupled anything, they would be used in microscope or laser support platforms. They aren’t. Hydraulic and pneumatic systems are most often used because they work. Cones aren’t used anywhere in any scientific equipment where reduction in vibrations is needed because they don’t reduce the energy in mechanical vibrations; they just shift the frequencies around a bit. The only place cones have any magic application is high-end audio -- home of the tall-tale tellers and the gullible who believe them. It’s not that cones can’t sound good, but the reasons given are just perpetuating a myth. Cones sort of look like the symbol for a diode in electrical schematics, so it is rather a cute tie-in to refer to cones as mechanical diodes, but being cute doesn’t make it true.

Have you ever read a review of a cone footer in which the reviewer also listened to cylinders, tubes, spheres, cubes, and pyramids made of the same material as the cone? No? Me neither. So how do you know the cone sounds the best? You don’t. If you could do this test, you might actually prefer some other shape to the sound of the cone. It all depends on your preferences and your system.

Materials themselves have different resonant properties. This is why brass horns sound better than tin horns or why an old violin or old guitar sounds different than a modern clone. The resonant properties of the materials themselves differ. The materials’ own resonant properties are as much an element of the sound of the device as the shape. Don’t get me wrong; the shape of the object does affect the sound too. Cones sound different than cylinders, which sound different than rectangular solids, which sound different than spheres. The bottom line is that all of these shapes transmit vibrations in both directions because they all couple the component to the shelf.

There is no single best footer for any audio system. Each system may need a small shove in a different direction to sound its best. Every owner seems to be chasing a slightly different-sounding system, so every audiophile may prefer some different footer. If you explore wood, each type sounds a little different. Soft pines sound terrible to me. Stick with harder woods and tropical woods. Teak, maple, cocobolo, zebra, and mahogany sound better to me than most other types of wood I’ve "heard." All of them, in the shape of blocks, sound better to me than most any cone I’ve heard. There was a time when I thought cones were required equipment for a serious high-end system. That was before I heard alternatives. Most audiophiles are probably in the same boat. You know cones improved the sound of your system, so they must work as advertised.

Spending lots of money on feet is essentially futile. Expensive feet merely sound different than free feet -- wood blocks, used vacuum tubes, marbles, ceramic insulators, pieces of pottery or brick -- and, of course, they sound different from commercial feet selling for much less. I really like the sound of Nordost Pulsar Points (four for $100), but there is nothing magical about them. They are machined from high-grade aluminum, have two pieces, and have a contact point that’s a little larger than a cone. I can’t get the sound of Pulsar Points from wood blocks or cheaper footers, so I’m willing to live with the cost. However, putting every component on Pulsar Points is a bit overpowering in my system. I prefer wood blocks under some components, Pulsar Points under others, and in a couple of cases, I have two or three different footers under a single component so none of them colors the sound of an essentially neutral sounding component too much.

You can put a component on an effective isolation platform like a LaserBase or Vibraplane. Both offer isolation in all three dimensions. Using footers under the component still changes the sound you hear, not because the footer decouples better or is a more effective mechanical diode, but because you prefer the resonant signature of that footer to the stock feet. The point here is that the isolation platform takes the equipment rack and floor completely out of the equation. The footer doesn’t have vibrations coming from the rack or floor that need to be "blocked" by a mechanical diode, but the footers still alter the sound of the component a little. That’s because it isn’t just the shape of the footer that is responsible for the sound of the footer. It’s the entire package -- of the footer: size, shape, hollow or solid, and the material it is made from.

So what’s the point? There are quite a few, actually.

  1. Use footers the right way -- as "tuners" for your system.

  2. Spend your money on good music or better components instead of spending it on expensive footers.

  3. If you are broke, you’re not out of the footer game; experiment with no-cost materials as footers.

  4. The right footer is neither hard nor soft, large nor small, exotic nor generic. The right footer is whatever sounds good and is one that you can afford without worrying that you spent too much.

  5. Good footers can be soft or hard, sticky or bouncy, light or heavy, pointy, round, square, or cylindrical. What sounds best depends on what you want and how your system sounds right now.

  6. Anything you put under your components changes they way they sound to some degree. If you don’t hear the change, the degree may be inconsequential or you don’t listen to the sorts of things that are changed by different footers. You are probably lucky; enjoy not having to spend money to get footers that sound a certain way.

  7. The bigger, longer, heavier and denser a footer is, the more it will tend to affect lower rather than higher frequencies. The smaller, shorter and lighter a footer is, the more influence it will have on higher frequencies. (This is a reference to what you hear from your audio system, not to how the device transmits resonances.)

  8. Emphasized mids or highs can make it seem like bass has been reduced. Emphasizing bass frequencies can fool you into thinking you hear less detail or less treble energy. Don’t let impressions fool you into misunderstanding what you are hearing when you change or add footers.

  9. Putting something on top of a component changes the sound as much or nearly as much as putting footers under the component. This includes putting footers on top of the component. Do you want to disprove the mechanical-diode myth? Put your cones on top of the component instead of under it. The sound is still pretty similar! It’s not identical, though. The stock feet will move things around somewhat, but the cones on top will carry 50% or more of the sonic signature you hear when you put the footers under the component.

That’s the rant for now. Good listening!

...Doug Blackburn


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