The drivers in a speaker cabinet will be positioned more ridgedly with spikes underneath, probably making them able to eek out slightly more detail.
Will |
When a speaker produces sound, a driver moves back and forth. It takes energy to move that driver. If an enclosure is not secured to the ground in some way, the moving driver will also cause the cabinet to move slightly. When the driver causes the cabinet to move, it is using some of it's energy to move the cabinet instead of moving air. You want the cabinet to be secured to the floor as best as possible. Try pushing over a speaker that is sitting flat on the floor and then try it with a speaker properly set up with spikes. If it's done correctly, there should be no movement. Without spikes, the bass will be more limited than with spikes. It does more than that though. It has nothing to do with air underneath the speakers. Otherwise, stand mount speakers would be worth nothing. |
Spikes are, by definition, pointy, so the contact pressure between the spike and the floor is much higher than if the speaker were supported by a large area, like the wooden bottom of the box. Therefore, the spikes will dig through any soft floor, such as carpet, until they hit something hard and unyielding, like wood or concrete. A speaker on spikes will have a solidly-mounted feel to it. Audiophiles who believe that woofers can move enclosures think this is important. (Actually, woofers don't move enclosures, as can easily be determined by hanging a speaker with cables). If there is any advantage to spikes I would bet that the resulting air space under the speaker acoustically decouples the speaker from the floor surface. |
It's all about reducing transmission of cabinet resonance from the speaker to the floor. This way you hear the vibrations of the driver, not the vibrations of your floor. Energy transferred from the speaker cabinet to the floor effectively turns the floor into one large transducer and, as you can imagine, a floor doesn't make a very good speaker driver. If a perfect speaker cabinet with no resonance could be designed, then there would be absolutely no benefit to putting that speaker on spikes. Unfortunately, no such perfect speaker cabinet exists, so we put spikes under our speakers to cut down on the transfer of vibrational energy to the floor. Incidentally, this is de-coupling...not coupling. Spikes do not, nor ever have coupled a speaker to the floor in an acoustic sense. Yes, they do anchor a speaker in the physical sense, but that has nothing to do with acoustic coupling. This will start a war, but I'm tired of hearing it wrong. Acoustic coupling refers to efforts to maximize vibrational energy transfer. To do it with a speaker, you would remove the spikes and put weights on top. Try it and see how that sounds. Then try de-coupling with spikes...you'll never want to be without them again. |
Actually, woofers can move enclosures. Try putting your cell phone on vibrate mode and set it on the counter. Watch what happens when it rings. It doesn't stand still.. |
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I have achieved substantial improvement in the sound of tower speakers that were already spiked on a carpet, by placing them on a spiked stand on the carpet. I think that having the speaker lifted away from the carpet (even that it was already on spikes) seems to help the sound. I can't even begin to speculate why this is true. I don't think its tweeter height, as I do experiment with seating position height. I've done this with with several pairs of Thiels, Proac 2.5, Spendor FL-9 and now Silverline Sonatina II's. The degree of improvement always surprises me (you'd think I'd learn, but nah... ; - )
Art |
Just to add to Goinbroke's correct explanation of what spikes are all about, the decoupling of the speakers will give an impression of less bass but in reality there will be more extesion in the lower region (less boom) and not only that but the overall sound will be cleaner. |
I'm going to be lazy right now and not do the actual math, but the length of a low bass signal is about 20 feet or more, if I remember correctly. A space of 1-3 inches doesn't greatly diminish its transmission.
This leads me to another discussion that a friend brought up. If my listening room is 18 feet long by 12 feet wide, is there a practical limit to how low a bass signal I can hear in the room? That is, if the length is shorter than the distance between the low-bass waves, does that stop me from hearing them?
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S7horton...Woofers do not move speaker enclosures. To answer this perrenial question (in my own mind) I have suspended speakers with rope and looked for movement. None observed. None at all. Others who have actually suspended speakers agree. People who sell spikes disagree.
Pbowne...Air space below the speaker will permit the LF pressure wave to pass below the enclosure. This has nothing to do with the wavelength of the sound. Tall skinny speaker stands will do the same. |
20 Hz cycle is 53 feet long, 20khz is less than an inch if merory serves me right. |
Pbowne: Correct, but totally off-base. You are right that 1-3 inches of space won't do anything to affect the transmission of low bass sound waves. Unfortunately, that's not the transmission that's in play here. What spikes help with is reduction of the transmission of vibrational energy from cabinet resonance due to a reduction in contact surface area between speaker cabinet and floor. Cabinet resonance isn't only caused by low frequency waves...any frequency can cause it. Which frequency does cause it in a particular speaker is determined solely by that speaker's cabinet design and construction.
To answer your question, the answer is no. Think of it this way...your ear canal/eardrum is only about 3/8ths of an inch across, does that mean we can't hear any frequency with a wavelength longer than that? Low frequency waves, as you correctly point out, have huge wavelengths. Unlike higher frequency waves, these suckers don't care about walls, or even our heads and simply pass right through. You will still hear them just fine, provided they are still in the audible range, that is. It is standing waves that are affected by room size, not sound waves coming directly from the speaker. Hope that helps... |
I placed spike under my speakers cuz it look good.. |
Eldartford is correct. No decently made cabinet is going to be moved by a lightweight little driver. Vibrated/resonated, yes, but pumped back and forth by a driver...no way. Eldartford's experiment is the perfect way to prove that and to clarify what he said: Idiots who don't know why they sell spikes disagree.
S7horton, that cell phone on vibrate isn't moving in response to a driver since in vibrate mode it isn't connected to one. It's moving in response to a small electric motor with its driveshaft connected to one side of a small weight, purposely creating an unbalanced rotation. Take one apart, if you doubt me. Ever had sore muscles? It's the exact same system used to make a massager. |
Some spikes are more cone shaped than others. Cones run one way when it comes to vibration. They 'drain' vibration from the speaker cabinet and dont permit vibration from traveling up from the floor. Thats why with cones under components and stands you get less vibration.
As for speakers moving, I have seen speakers and subs "walk". Its the vibration of the cabinet that you are trying to reduce. A drivers motion will be more precise if its 'working against' a solid stationary baffle to start and stop from , as opposed to a vibrating baffle. Spikes ususally improve the sound by giving the drivers a less resonant platform so they work better and also by reducing the sound you may hear from the cabinet itself. |
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. |
The idea that spikes "drain" vibrational energy from anything is quite possibly the most absurd idea I have ever heard. It is not only totally ridiculous, but physically impossible. |
Get me into trouble? Yes, I could cleary see how posting on an audio related forum could get me into trouble....
It's clear by your response you believe you are much more intelligent on this subject than me, so we'll leave it at that.... |
I started this because I am looking into VMPS ribbon tower speakers, and Brian does not suggest using spikes, these speakers have slot loaded bass, I have AR-9 Towers now wich I cant imagine putting on spikes, but the VMPS designers recomendation got me wondering..wich is why I posted this thanks all for your knowledge |
S7horton..."knowledgeable" on this subject, perhaps, but that's not the same as "intelligent". |
I don't use "spikes", I use Audiopoints.
These actually do work.
I never confuse "spikes" with Audiopoints, since they are totally different devices, that happen to look similar to other spikes.
Tom Lyons
Starsound Technologies |
Twl...Real question....What makes Audiopoints different? |
OK, then let me rephrase:
The idea that spikes or cones or Audiopoints "drain" vibrational energy from anything is quite possibly the most absurd idea I have ever heard. It is not only totally ridiculous, but physically impossible.
Feel better now?
With that said, note that I do not claim that they do not work, or do not help to improve the sound of speakers put upon them. In fact, my opinion is quite the opposite. They DO work and the effect they have is easily discernible in many situations. They just don't bring about that effect by draining vibrational energy as Blkadr suggested. This is an absurd concept which has no basis in physics or fact. |
The idea that a cone can act to decouple and block vibration sounds no less absurd than the notion that cones can channel vibration. If the large surface area of a cone is in contact with the chassis of a component and the componenet is vibrating due to 'airborn vibration', the cone will vibrate also. I submit cones can reduce vibratoin in the chassis even if it is resting on an decoupled shelf. If this is so, then where is the vibration going? Is it dissapated as heat at the cone's small contact point? Or do you think that the only effect is decoupling?
I have seen cones reduce energy in a component that was sitting on a decoupled shelf. I dont think my idea is absurd. |
I went different route. I baught at wallgreens DrSchool's Air-Pillo Gel shoe insoles (flat) and placed them under the speakers. A pair per speaker, $4.80 per pair. The sound improvement is huge! Spikes don't work. |
El, to answer your question about what makes Audiopoints better, here are some explanations.
The material and geometrical shape of the Audiopoints make the difference, based upon what we want to achieve.
Audiopoints do not "drain", nor do they "dampen" by design.
What they do, is provide an evacuation path for the vibrations to do what they naturally "want" to do.
According to the 2nd Law of Thermodynamics, which you are certainly aware of, all energy will seek the ground state via the path of least resistance. Vibrational energy will do so, just like electrical energy will. Ground states can vary, normally based upon mass, with the earth being the most commonly used mass for this destination of the energy.
If a path for this vibrational energy is not provided for the energy to seek the mass of the earth, then it will seek other routes to dissipate the energy, generally running around and around inside the equipment chassis, until it is exhausted.
If a path is provided for it to seek the larger masses of the house/foundation/earth, then it will take that route, as long as it is the least resistant one. This path must be easy for the energy to travel in, and very rapid, for our audio purposes.
Audiopoints use a specially formulated brass material, which is hard, with low lead content, for this purpose. It also uses specialized shape.
These things working together provide an pathway for this energy to transfer to the higher mass earth to be dissipated to the ground state remotely from the equipment.
We never say that vibrations should not be dissipated, but that they should be dissipated somewhere else besides in the equipment or stand, not locally. We also do not claim to eliminate vibration, but only to reduce a large percentage of the unwanted vibrational effects on the equipment.
Now, how do we do this?
We have designed a product which utilizes the reduction of Coulomb's Friction in the system, to improve the speed of the evacuation path. If Coulomb's Friction in the junction between the equipment chassis and the "cone" is reduced, then the ease with which the vibrations can transfer becomes much better. Then, the material and geometry provide an optimized route for the vibrations to travel earthward. A "White Paper" written by mechanical engineers is available on this subject, on our website.
For our products to be best used, no intervening items should be between the equipment chassis, our products, and the floor. Sometimes people put things in there, and it can reduce or defeat the performance of our products. We make various products that are different heights, including racks, so that people can get the benefits of our engineered pathways, at different heights of the shelving, and not have to resort to using other materials and devices between the audio/video equipment and the floor.
That is basically it. All we provide is a path for the energy to travel where it will eventually be dissipated by the earth, not returned into the equipment chassis to be recirculated. All based on solid physics, and borne out in audible performance. The math for the Coulomb's friction proof is shown on the white paper on our website.
The issue here, for us, is not to make some kind of "laboratory grade isolation table". What we do is provide a system which will improve the listening pleasure to the owner of the audio system, by addressing the unwanted vibration effect issue to a signifcant extent enough to make the sound better. We don't claim "perfection" or anything like that. We claim that using our products will improve the sound, in a way that doesn't have "deadening" effects that are common with local damping schemes. And in comparison to most local damping schemes, the sound that results from use of our products is preferred by many users, because dynamics and lifelike sound quality is preserved.
If you have very deep technical questions, I can refer you to our mechanical engineers, who can address these, as they may be beyond my abilities to answer(as a non-engineer). |
Tom, help me understand why vibrational energy wants to go to ground?
I understand that in an electrical circuit with a anode and cathode, applying a PD will cause motion in the circuit and that electron flow will occur via the path of least resistance. I don't understand how this propagates in a component that has self-induced vibration from the motion of internal components, and/or airborne induced vibration. How is there a natural force that sends vibrational energy looking for an 'out' via ground/earth?
I'm sure you are right, I just need help understanding it.
Isn't it more like a convection effect, and doesn't 'drain' and 'evacuate' basically mean the same thing when convection currents are considered? A transfer of energy I can understand, but analogizing it as a polarized conduction as per an electrical circuit needs more explanation.
It's a fascinating subject, thanks for sharing your ideas.
Rooze |
Rooze, good question.
Basically it pertains to the thermodynamic laws, which state first that energy cannot be created or destroyed, but can only be transferred; and secondly that energy will seek the ground state via the path of least resistance.
This applies to all forms of energy, including vibration.
When a body becomes excited by an external source(such as airborne vibration), then energy has been transferred into it from that external source. Its energy potential has been raised.
This energy will then seek its own way to be transferred somewhere, because the energy seeks to be transferred until it reaches its ground state(at which it is no longer in a state of excitation).
Where it will be transferred to, is decided by the path of least resistance that it can access.
Since high mass things, such as the earth, have a large propensity to be able to absorb many forms of energy, and dissipate it, this is ideal for the energy to be absorbed into, because it can become fully dissipated quickly and easily there. And there can be high mass things(like concrete, lead, and stone blocks, etc) that can act as a "false ground" or ground plane that is of low enough potential, compared to the excited body, that it can act in this role to an extent that it can deal with the amount of energy involved.
However, these high-mass and low-relative-potential bodies may or may not be easily accessible to the energy, due to many things, and the result is that the energy goes where ever it can to be dissipated, including vibrating everything it can get to, in an attempt to dissipate it as heat and friction, or to be dissipated in many different lower mass items that it can most easily get to.
One thing is for sure, it will try to go somewhere.
By recognizing the behavior of energy in this way, we can then direct the energy where we want it to go, much like a wire would do with electrical energy. A wire is a much easier path for electrical energy to travel, than it is to jump across the air, so it goes on the wire, as long as the other end of that wire is attached to a device with a lower relative potential.(Maybe not a perfect analogy, but illustrative of the concept). And so it is with other forms of energy too. By creating a "path of least resistance" for this vibrational energy, we can direct it to a place where it will be less detrimental for our purposes of audio listening.
That's all there is to it. A simple matter of understanding the laws of thermodynamics, and applying appropriate technology to work with them.
No, our systems do not do this perfectly, and maybe not even close to perfectly. But, they do it well enough to make an audible difference in the performance of the audio gear that we are trying to improve. The results are an audible improvement in sound systems, and a visible improvement in the picture of video systems. While perfection may not be attainable, a system which provides a significant enough improvement is deemed worthwhile by many users. And that is what we offer.
We recognize that other forms of vibration control, such as local damping with rubber or foams can be effective. However, we have found that a common side-effect of local damping schemes is "deadening" of dynamics and lifelike sound. One of our design goals was to reduce the unwanted effects of excess vibration without "deadening" the sound. Since our system leads the vibration to a remote place to be dissipated, the unwanted side-effects of "deadening" the sound do not take place when our products are used.
Not every audio hobbyist subscribes to our concepts and methods, but there is no doubt that it is an effective way to deal with unwanted vibration in entertainment systems. Whether one individual prefers it, or another method, is solely up to that individual's tastes and ideas of good sound. |
Tom,
Thanks again. Your explanation answers my questions, and raises others! (that's a good thing!).
I honestly think that we haven't scratched the surface as far as vibration control of audio components goes. I've read some theory from Michael Green and find some of his opinion pretty radical but at the same time quite thought evoking, as yours are.
I'll follow your threads with interest.
Rooze |
TWL, without disputing the benefits of spikes, whether it be for isolating or "draining" and I do believe that there are benefits in using spikes, I must take you to task for mis-using the 2nd law of thermodynamics as the explanation for the "vibration" draining effect.
The 2nd law does not refer to any energy going to ground through the path of least resistance.
As quoted from the Perry Handbook, the 2nd Law is "The Entropy change of any system and its surroundings, considered together, resulting from any process is positive and approaches a limiting value of zero for any process that approaches reversibility."
The second law requires that the entropy of an isolated system must either increase or in the limit, where the system has reached an equilibrium state (the vibrating speaker system, isolated by the spikes), remain constant. The vibrations are converted to heat.
For a closed but not isolated system (the vibrating speaker system tightly connected to another mass or floor),it (the 2nd law)requires that any entropy decrease in either the system or its surroundings be more than compensated by an entropy increase in the other part.
The short of it. Energy tends to goes to its lowest expression of it. Heat (Entropy) is the lowest level of energy. For an isolated system (suspended speakers is as close as one could get, I guess) the vibrations are converted to heat through absorption in the speaker systems mass. If the speaker system is not completely isolated some of the vibration is also absorbed by the attached mass.
Even if one uses the "vibration draining" description for an explanation and I can see where this is an attractive explanation for the non-technical person, the use of the 2nd law as the explanation for the draining of vibrations to ground is stretching an analogy too far.
I feel that the benefits that we derive from spikes is that we isolate the speaker system from the floor and keep the floor from vibrating because of the speaker. A vibrating floor definitely doesn't help with the speaker's perceived performance. There are enough things vibrating in the listening room from airborne vibrations, without having to deal with direct excitation of the room surfaces by the vibrating speaker system. This also has the benefit of not exciting some of the sources (turntable) which can be affected negatively from outside vibrations. Sooner or later, the cartridge/arm has to be protected from outside vibrations.
I respectfully submit that the engineers with whom you work probably used the "drain to ground" analogy because they wanted to somehow explain the benefits to a non-technical person. They have, I believe, underestimated your intelligence and knowledge from what I have gleaned from your excellent posts on turntable and arm performance.
With respect,
Bob P.
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First Law....You can't win.
Second Law...You can't break even.
Vibration must be converted to heat in some damping medium. If you "drain" vibration to the earth, you are contributing to global warming. Shame! |
Thank you Bob, for your comments.
Much appreciated. |
I have to stop you fellows.
Spikes "do not" drain anything. They simply act as mechanical couplers.
If a speaker is "reacting" to its drivers by vibrating, then the spikes will couple the cabinet with the larger mass (the floor) and reduce the reaction from the drivers, by adding that mass.
It is that simple. All this mumbo jumbo about shape of the cone, and metallurgy and such is "mish mash".
Spikes are NOT Drains, for they don't "drain" anything.
They simply make it more difficult for the drivers to have a reactive (force) effect on the cabinet.
These long thermodynamic answers are making me dizzy, their so full of mis-information and mis-interpretation. |
Everybody can have it their own way.
I don't care anymore.
Do your circle game and have fun.
I don't have any more discussion in me.
Good bye. |
Ok, maybe 'drain' was the wrong word, 'transfer' might be more accurate. Please take a minute to consider this experience I had.
A friend had a TT that had three relatively flat aluminum cones that served as feet. The flat side makes contact with the flat bottom of the turntable. The turntable sits an a welded target stand. He put on a classical lp and during a loud passage that had a lot of bass the cartridge mistracked. He said, "that never happened before". I checked the cone footers and found that he had absentmindedly put them facing up, not down. We flipped them over and replayed the passage. Of course the tracking problems were gone. You could feel with your fingers a huge difference when you touched the TT base. We removed the cones and placed the TT on a folded over towel and tried it again. We could feel more vibration in the TT base than when the cones were under it (correctly).
This (unscientific) experiment suggests to me that the cones do more than isolate the TT base, they 'transfer' the 'airborn' vibration that the base was picking up from the music to the target stand. After seeing that the TT would mistrack when the cones were upside down, and not when the TT sat on a towel, it would be hard to argue that the cones were not 'transfering' energy from the stand to the TT base.
I dont understand why it is so hard to imagine that it is possible for vibration to be transfered from one object to another. If its just 'isolation' thats taking place, where does the energy go? |
You wrote:
This (unscientific) experiment suggests to me that the cones do more than isolate the TT base, they 'transfer' the 'airborn' vibration that the base was picking up from the music to the target stand. After seeing that the TT would mistrack when the cones were upside down, and not when the TT sat on a towel, it would be hard to argue that the cones were not 'transfering' energy from the stand to the TT base.
I dont understand why it is so hard to imagine that it is possible for vibration to be transfered from one object to another. If its just 'isolation' thats taking place, where does the energy go?
I write:
Oh there is no arguing that "some" of the energy can and is tranfered, but that is not what is causing the difference.
First off cones don't generally "isolate", they "couple".
Setting the TT on a towel "isolates" the TT from the stand, and allows the airborne vibration to have a larger effect on it.
Setting it on cones, creates a mechanical "coupling" to the mass of the stand, and reduces the affects of the air borne energy, by increasing the "mass" seen by that energy.
My "key" point was this "draining" verbiage. Like each cone or spike is a drain and vibration runs down them like water from a sink. That is an incorrect and silly notion.
The interesting thing in audio is 1/2 the time is spent creating beautiful "vibrations" and the other half is spent "fighting" damamaging vibrations. |
Hey TWL has left the game and thats a bad thing .... Eat beans and gather round the campfire and continue the storytelling..I'm leaving before the swamp gas rises anymore. Regards..the other Tom |
Eldartford, nice summary! 1st law - can't win. Conservation of energy and mass or zero sum or a tie.
2nd law - entropy can only increase, therefore no "break-even". No comment on drainage systems, sewers not being my expertise!
Salut, Bob P. |
I bought a pair of used KEF 104/2s that have threaded recepticles on the botttom. I assume that they have been used with some type of spike. What brands of spikes do you folks prefer, and are threads universal? The floor has medium pile carpet.
db |
