Spikes versus wall coupling

I have a Polk SRS-SDA 2.3 speakers. They are 185 lbs each and currently sit on thier furniture glides on a maple floor, over subfloor, over trusses. No carpet. They have a passive radiator for lowest base at the bottom of the cabinet, and I roll to a subwoofer at 60HZ. I like to move them occasionally so have been reluctant to use spikes.

My question is what am I really missing sound wise? And would wall coupling do as well as spikes. I can put them on some marble slabs,as another alternative, or remove the glides and have the bottom fully sit on the floor, o rthe marble. I do not have a turntable. Or should I spike them despite the hassle?
You might try a platform/shelf under the speaker and on top of your glider(between) There are many brands most work well.---I had the same setup but I ain't advertising for this co.---Go to 'tweeks' and see what they got new or used.
Personally I would not advise spikes. Why would you want to couple these speakers to a wood floor. In fact, with the mass of these speakers they are already more than adequately coupled. In my view you should want to isolate them from the floor, if anything, so you don't have to listen to the results of floor vibration any more than necesary. FWIW, I can't think of a single reason to couple speakers to a wall.

Now don't laugh too much at this suggestion, but you might consider using some hockey pucks and some felt pads on the bottoms of the pucks. That way you get some isolation and still have the ability to move your speakers about.
I am not laughing at all. This is my feeling too, that isolation would be better, unless you are trying to bleed vibration out of the speakers. With isolation I would think that you dont have to worry about vibration generated by the speakers going into the floor and then rebounding back into the speakers at the wrong time. The pucks or other devices make sense, but why not directly put the felt or cork under the speakers?
My experience is different. Every speaker I've ever lived with sounded materially better when firmly coupled to a solid floor, including suspended wooden floors which is all I've ever had in my listening rooms. The most common difference I hear is increased definition and articulation in the mid-bass through lower midrange.

Most recently, I was suprise by the improvement in my Eidolons when I replaced the stock spikes with Walker Audio Valid Points. Given the mass of the Eidolons and given that they were already spiked, I wasn't expected a difference: but the difference was very material.

The key point is that all systems and floors are different; you'll never really know what you may be missing until you try it and then listen for yourself.
With your speakers I'm afraid the mass would compress the felt so much that it would just become another mudium for transmission of vibrations. Cork could work and those dense rubber mats sold at Home Depot combined with some felt so you can push the speakers about could also work. Not necessarily elegant solutions but probably as good as most. IMHO most of the vibes from speakers that are really destructive are air borne.
There is a product which might serve your needs. They are called "Superspikes". It's a spike which fits on top of a flat disk. However, it's all integrated into a single unit. I don't know who manufactures them. However, you can see them at www.uhfmag.com Just link to "The Audiophile Store" when you get to their homepage.

The purpose of spikes is to decouple the speakers from the floor. The tiny point creates an impedence mismatch (mechanical, not electrical impedence) It makes it more difficult for sound waves to pass through to the floor and shake, rattle and roll the rest of the house.

If you couple a speaker to wall studs, the objective is the same as using a heavy equipment stand. You want to use the mass of the wall and attached structure to absorb any vibrations from the component and disspipate gradually. It also works theother way. It absorbs and dissipates any vibrations in the environment from travelling into the component.
Rushton Your point is well taken:)
But I looked at the prices on Walker - yikes! Any lower cost points that you like, perhaps mapleshade? I think that I will try both points and cork (or cork-pucks) and see what sounds best
A properly designed point or spike will provide a geometric path way for resonant energy to exit thru the point and into the larger mass it is direct coupled with. There are discs on the market which when placed under the coupling point increase the surface area of the point and provide surface protection of wooden materials. Your wooden floor is much more massive than your speaker so you should direct couple your Polks. The force generated by the massive radiator will only modulate the cabinet over and over again unless the speaker is properly grounded or coupled to the floor..Tom
Thanks you all for your input. I get the impression that it has never been fully settled whether it is better to isolate or couple speakers. Am I correct that here are two schools of thought? Is the same true for components (some folks isolate and some couple :)
Tom, If you want to couple speakers as massive as these to the floor why would you need to do anything except let the wood bottom rest unobstructed to the wood floor? That would certainly allow all of the vibrations to pass directly to the floor. In fact I think a case can be made for the proposition that if you insert an intervening devise you might successfully limit the vibrations that may be transmitted from the speaker cabinet to the floor to those vibrations that the intervening devise can pass. Assuming that the devise is not limiting, how exactly will it improve the direct contact of the bottom of the speaker?

One last question, once you have all of the vibrations being transmitted to the wood floor, if you have similar devises under your TT and equipment racks how to you keep the vibrations from going up into the TT and other sensitive components in you rack? Or do the vibrations only flow in one direction?
Hi Newbee,

You are quite correct. Coupling one of the main sources of vibration (the speaker) to the floor will allow that unwanted energy to travel towards the components. If they are also coupled to the floor (by rigid points, rigid spikes, a slab of rigid stone or rigid wood) the vibration will travel up into the bottom of the component. Any rigid device allows vibration to travel in BOTH directions - down out of the component AND up into the component.

In the case of speakers, if you rigidly couple them to the floor they will also be subjected to external sources of displacement (vibration) such as exterior traffic (trucks, autos, busses, airplanes, trains, freeways) and natural geological seismic activity. That will negatively affect their performance.

Best Regards,

Barry Kohan

I am a manufacturer of vibration control products.
I'm a relative newcomer to to this, so if I am coming from left field, forgive my ignorance. They are many materials, polyurethanes and foams for dampening vibrations and absorbing sound. Wouldn't using some of these things work? Sorbothane absorbs shock and vibration very well. It is an expensive material, $105 for a 1/4"x24"x24" sheet, but it seems it would be very effective in dampening vibrations coming off of a speaker and stop vibrations going to a speaker, CD player, turntable, etc., etc. etc. There are sound absorbing panels and vibration damping coatings that you can apply like paint to ventellation ducts and sound/vibration dampening panels that could be used under the flooring to improve the overall accoustics of a room. I looked in the McMaster-Carr catalogue and found a lot of sound and vibration control stuff that seemed would be perfect for tuning a room or controling unwanted vibrations and sound. Why not use some of these materials? Am I all wrong on this?
If vibrations are not eliminated at source, there are two things you can do. First, you could isolate (decouple) the vibration. Second, you could transfer the vibration to another object (couple) and dissipate it in a non-audible form of energy. Rather than think of these as two "schools of thought" which are in opposition, think of them as two ways to achieve the same result. They can be used together. It is not necessarily one or the other, although one may be better in a particular application.

Using spikes or cones under speakers or electronic components isolates vibration. Because there is less surface area between the vibrating object and what it is vibrating into, there is less energy transfer. To a mechanical engineer, the concept is "mechanical impedence". It is a differennt concept than electrical impedence to an electrical engineer. What happens to the energy which is not dissipated out of the component? Well, that's part of the job of the component's designer. For a speaker, the energy might be channelled and directed out of a speaker port. Or it might be damped by stuffing in the speaker. For an electronic component, the chassis might be damped with a compound to minimize metal chassis "ringing". Just as the cones or spikes keep energy from the component from going out, the impedence mismatch also prevents vibrations from the environment from coming in (excluding air borne vibration).

No spike or cone is perfect. Some energy will get through. Now you can use the second technique. Take the energy which vacates the component and convert it to a non-audible form (eg. heat, or shift it to a different frequency). The laws of thermodynamics state that energy cannot be created or destroyed; it is only converted into something else.

One thing you can do is to couple the component to something massive. A small vibration in a large mass will be more easily damped. If you put an amp on a massive stand, (such as metal filled with sand, or on a granite slab), the vibration can be dissipated in the stand. Because the vibration is relatively small, it is less likely to vibrate the stand and it will likely be converted into heat and dissipate. Coupling a speaker to the floor or wall allows the speaker to be coupled to something massive.

Unfortunately, mass is not the only variable. All matter will resonate at some frequencies. If the transferred energy causes the mass to resonate, the resonance could be audible, or come back into the component. Here is the problem with wood. It resonates. That's why violins and acoustic instruments are made of wood.

If you can couple to a concrete floor, you can get damping from mass without audible resonances. If you couple to wood, you get less mass, therefore less damping, plus you are likely to get audible resonances. Coupling to wood structures and not getting resonances is extremely difficult. It's not impossible, but it's hard to do unless the vibrations are small. Turntables can be coupled to walls with a wall mount turntable stand, but a speaker simply produces too much vibration. It's luck (and construction) more than anything else if it happens to work for your speakers. And it doesn't prevent structural vibrations (footsteps for example) from going back into the speaker. After all, the vibrations go in both directions) Decoupling with spikes is more likely to be effective for speakers than coupling. It doesn't connect you to resonant wood, and it makes it harder for environmental vibrations to travel into the speaker.

Remember that you can use both.

Put an electronic component on cones or spikes and it helps to prevent vibration from entering the rack and vice versa. If vibration does enter the rack, use a heavy, massive rack that is non-resonant at audible frequencies so that the energy that does escape through the spikes is damped. Now put the rack on spikes so that energy in the rack doesn't escape into the resonant floor and so that resonant energy doesn't come up into the rack. Put the rack on a granite slab so that energy from the rack is dissipated by the mass of the non-resonant slab. Put the slab on spikes so energy from the slab doesn't go into the floor and resonate, and so that floor energy doesn't come into the slab. This is an extreme example, You take it as far as you want given your budget and your evaluation of whether it's cost effective or not in terms of audibility. The point is that it's a series of decoupling techniques that limit energy transfer, combined with coupling to massive, non-resonant objects to damp the energy that does escape.

It's the same thing with speakers if you choose to couple, only instead of a massive rack, you're using a massive house structure.

Put speakers on spikes to decouple. This helps to keep the energy in the speaker where it is damped in the speaker by the cabinet or stuffing. The spikes also limit energy coming into the speaker from the outer environment. In addition, the spikes also keep the speaker energy from energizing the resonant floor.

Because electronic component vibration is small, coupling to a massive, non-resonant rack is a good way to go, especially since you need a rack anyway to hold the gear. You can then add cones as a final tweak if you think that it makes a difference for whatever miniscule vibrations which are left, or if there are environmental vibrations coming into the rack and then into the component(or put spikes on the rack)

For speakers, the amount of vibration is so large, the only thing massive enough to couple to for damping is your house. But if your house is wood, coupling is a problem because of the resonant wood. So the more efficient approach for speakers is to decouple with spikes.

So for reasons of practicality, tame component resonances by coupling to massive, non-resonant racks and tweak with cones; tame speaker resonances by decoupling with spikes.
Newbee way back when my oldest sister had a senior class prom party at my parents house, I remember my father being really pissed off the morning after..Reason was the new hardwood floors were dented from all the young ladies who wore 4 inch heels the nite before..You didn't see footprints from the soles of the shoes the guys wore even though the guys weighed twice as much. The young ladies' weight were more effectivly coupled to the wood floor than their much heavier male counterparts. A speaker cabinet while playing is not resting at a standstill.In fact the cone motion is modulating the whole cabinet.This cabinet motion can be as large as the exsursion of the tweeter of that same speaker..The most effective way to limit this loss of energy, this out of phase energy, this self perpetuating generation of resonance is to direct couple the speaker to the floor as described. Some coupling devices I know of are designed to limit the entrance of frequency's below 4 hz, so mother nature's blowups are less imposing on ones audio..Tom
MarkPhD Thank you for your detailed response. I may be dense but if you are trying to decouple the speakers by using spikes, could you not also decouple using cork, felt or rubber, or combination products such as (VIBRATION ISOLATION PADS or Klein Tech Systems Iso-Damp Discs vibration isolation pad - both from the tweeks page) and get the same result without damaging the wood floors and still being able to move speakers more easily.
I assume these absorbant materials do not pass vibrations easily. Are you saying that spikes are better becuase they also anchor the cabinet and prevent the small cabinet movements that rubber etc might allow?
Gammajo, you can decouple using anything. It is the small surface area that makes spikes good as this is what increases the mechanical impedence. If you use a product with a larger surface area, you will get less impedence and more energy transfer. How much less, and whether it is audible would have to be the subject of further debate add experimentation. I don't quite know what to make of little rubbery decouplers like isobearings or pucks. With a larger surface area compared to spikes, they are not as efficient as decouplers. On the other hand, if they wiggle a bit, the movement may damp vibrations. So you may be losing a little bit of decoupling, but gaining a little bit of damping. Remember that isolation and coupling can both do the same thing. I really don't know how to answer the questions in your latter post. We're pretty close to my limits of knowledge on this particular subject. I was hoping that the Bright_star_audio person who posted might kick in a few words. Bright Star make reputable products and should be able to add some insight. Sorry I can't help further.
MarkPHD thank you and all others who have posted. I am clearer now on the issue. For me logically it makes sense for the speakers to have something very solid to push against so that the movement of the drivers is all in the correct direction, and spikes also isolate due to their small surface - cork, felt and rubber would tend to compress under 185 lbs speakers and behave more like a solid and transmit vibration, and therefore the spikes are most apprropiate.
For underneath lighter components with less intrinsic vibration I think these materials might be more appropiate to isolate the components, absoring vibration both from the component and from the shelf.
Hi All,

Even though there may be asymmetrical mechanical impedence between the point interface and the opposite interface of the spike there is still significant mechanical transfer occurring in BOTH directions. This pathway does not provide isolation. It allows vibration to flow up the rigid point or spike into the component that is placed on top of it. This problem is quite significant when components are placed on a rigid mounting but is still an important issue when speakers are placed on a rigid point.

Points have been a relatively popular method of mounting a speaker. Is it the best method for mounting a speaker? No. It does provide sonic improvements as compared to having a speaker sitting directly on carpet because the carpet does not support the cabinet effectively and allows it to deflect in reaction to the drivers’ movements. This creates Doppler shift as well as allowing some of the drivers’ energy to be diverted from the main task of making sound to making the cabinet move. A speaker resting directly on a hard floor does not usually sit as flat as we assume it will. Both the floor and the bottom of the speaker cabinet are not truly flat and “chatter” between the two does occur. Again, wasted energy. Placing three points under the cabinet does help the speaker become much more rigid and that is the main reason for their relative popularity. Three points does define a plane and that will naturally make the mounting more stable than without the points in place. Unfortunately, the spikes are not nearly as effective as other methods of transferring vibration out of the cabinet and they also do not support the rear two corners of the cabinet which allows them to be much more susceptible to internal resonance. The rigid mounting for the speaker also allows external sources of vibration to enter into the cabinet from the floor which causes a different source of Doppler shift contamination. This vibration is not sourced from the speaker and therefore has no relation to the music signal in the recording – it is exhibited as a general displacement of the speaker cabinet which lowers the overall dynamic range and interferes with pace and rhythm.

The fact that the support and interface we place under a speaker perceptively changes the sound clearly illustrates the insidious nature of vibration as it relates to an audio system. Almost every aspect of sound reproduction - tonality, spatiality, dynamics, coherence, etc. - is compromised by unwanted vibrational energy. That is the result of a disturbance in the relationship between frequency, amplitude and phase of the original signal that the audio system is reproducing.

As the speaker drivers are radiating acoustic energy into the room (the energy that we want - music) they are also sending energy into the speaker cabinet because of air pressure from the inward motion of the cone and by conducted energy through the frame and mounting flange which becomes unwanted stored energy (USE). This USE causes the cabinet walls, the crossover components, the connected speaker cable, etc. to vibrate (the drivers are also subject to compromise by their own vibrational energy that they've sent into the cabinet that is then reflected back towards them after a delay in time). The cabinet vibration has the most consequence towards corrupting the speaker's performance. If we were able to quiet the driver's acoustic output into the room and just hear the result of the cabinet walls vibrating I think we would be shocked as to just how much audible acoustic energy the cabinet would be radiating! THIS version of the audio signal would have a different frequency balance than the driver's output (it would sound muffled being dominated by the primary and secondary resonance frequencies of the cabinet) it would be lower in amplitude (but not uniformly lower because of the non-linear nature of the cabinet materials) and would be delayed in time (the amount of time it would take for the energy to leave the drivers, be absorbed by the cabinet and then be released into the air) thus affecting phase integrity. If we think about this 'smeared' version of the signal (which contains corrupted frequency, amplitude and phase) being mixed back into the original signal it is no wonder that USE significantly affects the reproduction and that altering the USE has an audible effect!

Now, just imagine if we make a significant reduction of USE in the speaker cabinet. The amount of audible difference would be profound. Placing high mass on top of the speaker cabinet will significantly increase the resonance frequency (a good thing) and decrease the amplitude (also a good thing) of the top panel. The weight load will then be translated onto the side panels with a related change in their resonance frequencies. Furthermore, the added mass will more effectively couple the speaker bottom to the top plate of the speaker support, the floor or more suitably to a high-mass high-absorption platform so the USE can be drained from the speaker cabinet.

If we used laser infrarometry to measure the displacement of the speaker panel we would see a noticeable reduction in displacement (vibration) when high mass is set on top. In addition, if a high-mass high-absorption platform is placed under the speaker, this multi-stage vibration control system forces the speaker to be more effective in its main task of reproducing music - the drivers do not waste their energy in making the cabinet or internal parts vibrate because the cabinet is far more resistant to displacement. The drivers have no choice but to use their energy more efficiently in creating music.

The most effective method for supporting a speaker would be a high mass element on top of the cabinet, a high-mass high-absorption platform directly under the speaker (on top of a rigid and strong stand for a mini-monitor) and a pneumatic base on the floor to decouple the speaker's energy from entering the floor and being transmitted to the equipment rack (the pneumatic mount must be designed in the correct manner so that it does support the speaker without allowing Doppler shift to occur). This configuration is highly successful in eliciting the peak performance from the speaker without a redesign of the cabinet or the component parts.

The other components in an audio system will also benefit by a reduction of USE in their chassis. Besides speakers, turntables exhibit the largest degree of improvement by proper vibration control. Since they are electro-mechanical devices it is almost intuitive to us that this be so but the purely electronic devices also benefit: tubes are microphonic, the master and sub-clocks (which are based on oscillating crystals) in digital devices are affected, a spinning disc inside a digital player will exhibit non-linear movement, all component parts (transistors, ICs, capacitors, resistors, wire, diodes, etc.) that process the signal become microphonic, motors, fans and buzzing transformers induce vibration into surrounding parts, and the list goes on.

What are the sonic results of vibration contamination? As we discussed, frequency, amplitude and phase are corrupted. Frequency balance is skewed: one portion of the spectrum is highlighted or diminished as compared with another. Brightness may increase, midrange may become too forward, and bass may bloat and become ill defined. Amplitude of the signal is changed: the dynamic range of an instrument and indeed the dynamic relationships between the instruments are altered. Phase integrity of the signal is deteriorated: the spatial relationship of the instrument with its environment and the spatial relationships between the instruments are altered. In fact, frequency, amplitude and phase are interrelated and changing any one affects the other two. If all three are affected at the same time (by the presence of unwanted vibration) the resulting cacophony significantly reduces the ability of the system to convey what is actually contained in the recording - and that's what audio is all about. Not just what sounds pleasing because it makes someone feel fuzzy all over but what is musically and emotionally fulfilling because it reflects the actual sound of the instruments as they have been captured in the recording.

When we eliminate the sonic results of vibration contamination we more accurately hear what the individual components in a system are doing. It is possible that these results might be misinterpreted by some individuals. For example: if a speaker is providing excess out-of-phase elements the size of the soundfield might INCREASE beyond what is actually in the recording. Bigger is not always. This individual will have adjusted speaker placement and acoustic room treatment based on this exaggerated sonic view of the soundfield. Once the out-of-phase elements are properly controlled by reducing vibration the size of the soundfield may become smaller in this incorrect set-up and the listener may say, "Oh, this is not as good as it was before because things are not as large." What they should be doing is reevaluating speaker position and room treatment to optimize the now correctly operating speaker. Once that is accomplished they will find that not only is the soundfield as large, if not larger than before, but the instruments are in proper relationship with one another and ambience is cohesive instead of exaggerated. Frequency changes can also be misinterpreted: in a vibration plagued system a too forward midrange during transients is a typical symptom. Some people might misinterpret this as the system exhibiting "good presence" or a forward brightness region is often described erroneously by some listeners as "good detail". The removal of the vibration will eliminate these effects. Some may feel at first, that the removal of these exaggerated artifacts is a step backward in reproduction, but what they are hearing in the now vibration free system are the possible cumulative effects of previous tweaking and/or component choices made with a vibration drenched palette. Once the problems caused by unwanted stored energy are removed some system choices may need to be reevaluated.

Best Regards,

Barry Kohan
Bright Star Audio

Disclaimer: I am a manufacturer of vibration control products.
Text correction:

In my last parapgraph the line should read: "Bigger is not always better."


Barry Thanks for your detailed reposnse. I have checked out your well recommended products and understand the theory. You state "A speaker resting directly on a hard floor does not usually sit as flat as we assume it will. Both the floor and the bottom of the speaker cabinet are not truly flat and “chatter” between the two does occur. Again, wasted energy"
Therefore, how do you ideally couple the bottom of the speaker to your platform, or other such masses. Do you use the isolating nodes, or have them flat against each other?
After reading this thread, I'm totally at a loss for words.

Have fun.
Hi Joe,

Optimally, the speaker will be place on the Plinth (top plate) of our Big Rock platform. The special coating on our products is not only non-resonant, it is slightly textured. This textured surface has the ability to contour to the bottom of a speaker allowing a significant increase in contact area compared to placing the speaker on a standard hard surface. We do not want a compliant material between the speaker (or other audio or video component) and the Plinth of the Big Rock. The Plinth is the conduit which directly routes the unwanted stored energy out of the component and down into the bed of sand where it is effectively dissipated as thermal energy (heat). It is critical that the vibration (mechanical energy) be dissipated as quickly as possible and placing the absorptive element as close to the component as possible is best for maximum efficiency. Attempting to route that energy through a multitude of materials and down into the floor (as most spike or cone manufactures describe) is not nearly as efficient or effective.


I agree with TWL, except I'm never at a loss for words. I think this thread is a vintage argument for the old saying what ever works for you must work. There are just so many theories regarding vibration control it's tough for folks like Gammajo and I to know what might work for our systems. Some one sez that spikes couple but cones isolate. Dense rubber couples. Lossy rubber isolates. The difference is(?) the mass of the speaker/stand. Who's to know. Then there is the "drain vibration" school of thought, which makes sense to me if you are talking about draining vibrations from a component which are exciting it's resonance frequency, but how do we insure that the materiel used to drain off this resonance actually passes the resonance frequency, and what happens when the devise actually hits it's own resonance frequency. Then there is the issue of vibration/resonance amplitude. At what point do these vibrations and resonances become audible significant?

Wow. Poor Gammajo has no more a solution to his question now than when he first asked his question. :-)
I personally am enjoying the thread, being the curious and obsessive type. I want to penetrate to a good understanding if possible. All your comments are helping me do this. I think I am leaning right now to just putting a big rock on top of my speakers and resting them directly in sand, lol. Unless of couse Barry's product is cheaper than I expect - just kidding Barry, you have been devoted in trying to explain this and I appreciate it emmensely and asked for a price quote today.
I am also an very intuitiive guy - make a living teaching meditation, and intuitively I dont like spikes.
Hi Newbee,

I can empathize with people who may feel overwhelmed with the numerous (seemingly) conflicting theories and the multitude of products on the market.

The most important aspect to vibration control is understanding the nature of the problem. Without that, it will not be possible to design the most effective means to deal with contaminating vibration. Most manufacturers only seem to consider floor-borne vibration that is sourced from the loudspeaker and do not address other sources and forms of floor-borne vibration let alone internally generated or air-borne vibration. It is also critical that the designer be very familiar with a wide range of materials and how they interact with each other as well as having the appropriate measurement equipment to assess how well the devices address the problem.


The best part of my day is when I turn on the music. As a thank you gift for all of you who have responded, I would like to turn you on to two recordings that I have recently purchased that are splendid. Both recordings are beautifully done. The first Is Al Lee's Ain't Playing the Game by MapleShade (acuostic guitar, great lyrics described as James Taylor with cojones). The second is Arcadi Volodos Piano Transcriptions by Sony - amazingly beautiful in everyway.
Gammajo, Thank you for your recommendations. Since you bring up Volados, I would most highly recommend to you his Schubert solo piano works on Sony. This is not only outstanding playing, an excellent recording, but who would ever have guessed that Volados could play such sensitive Schubert.

On another matter, you teach mediation - I'm on the other end, utilizing mediation extensively to resolve civil litigation cases before trial. Great system and tons of fun for those who are or would become skilled negotiators (you've added another person to the mix who requires more attention than the other side!). Keep up the good work.
Direct coupling if implemented and properly performed increases the likley hood of sucessfull resonance transfer.Ask your loved one for further comment..Tom
Newbee, I teach meditation not mediation. OM! Though through meditation I have absolute respect for the process of mediation. Both increase the peace in the world. Thanks for the Schubert tip - I love much of Schubert. Has Barry convinced you yet:)
Barry you have not provided for an exit stratedgy for vibration to vacate the speaker. In fact you have provided no way out at all.. by adding mass and dampening at the top of the speaker you have 2 totally opposed counter productive non exit paths.Tom
Hi Tom,

Thank you for your comments. It seems that I must have not been as clear as I intended. Please allow to explain again in more detail.

The vibration control system which I designed and described utilizes a high-mass, high-absorption platform directly under the speaker cabinet. The best implementation of this type of platform is the Big Rock which I created in 1985 and for which I was granted a patent in 1993. The Big Rock uses a quantity of sand to absorb and dissipate vibration from the component’s chassis or speaker cabinet that is placed on top of it. Virtually all “sandbox” type platforms which are discussed on the internet are copies of my original design. When used under a loudspeaker the entire bottom panel of the speaker cabinet is in intimate contact with the Plinth (top plate) of the Big Rock for maximum transfer of unwanted energy. Sand has the ability to absorb a huge amount of mechanical energy (vibration) by quickly and efficiently converting this destructive energy into more benign form – thermal energy (heat). As we know from the laws of physics; ENERGY CAN NEVER BE DESTROYED – IT CAN ONLY CHANGE FORM. I have used bold type because of the importance of this concept in our endeavor to control vibration. It encompasses every aspect of how vibration enters and contaminates the signal which flows through our audio and home theater systems and must be at the forefront of our thoughts as we design a vibration control system to most effectively address this problem.

There are multiple sources and multiple forms of vibration. The sources of vibration are:

1) Floor-borne vibration which includes; Vibration that is directly-coupled from the loudspeaker which transfers through the floor and up through the component stand into the feet of the component. Air conditioning and heating systems which send low frequency vibration through the building’s structure. Exterior traffic (trucks, busses, cars, freeways!, subways, trains, airplanes, etc.) which sends very low frequency energy up through the floor and into the system’s components. Natural geological seismic activity which sends extremely low frequency energy up through the entire building which contaminates the system’s components.

2) Air-borne vibration sent directly from the loudspeaker drivers through the air towards the chassis of the component (this also includes energy reflected off the walls, ceiling and floor).

3) Internally-generated vibration that is created within the chassis of the component by spinning motors, humming transformers and cooling fans.

Not all of these sources produce the same type of vibration. The vibration from the speakers as well as air-borne vibration are related to musical signal flowing through the system. Their sonic degradation to the system will be similar to a “ghost” image on a television. It will be vaguely similar but different in spectral content and have out of sync timing as compared to the original signal. The primary sonic symptoms of this type of vibration are a shift in tonal balance (typically excessive brightness and bloated bass), diminished transparency (detail and clarity) as well as degraded pace and rhythm. The secondary sonic symptoms include exaggerated dynamics for certain frequency groups and diminished dynamics for other frequency groups plus an alteration of imaging and soundstaging (either smaller than what is contained in the recording or an exaggerated version of what is contained in the recording).

The vibration from the other sources is not related to the musical signal which is playing through the audio system. The sonic symptoms of this type of vibration are diminished dynamics due to an increase in the noise floor and a general lack of coherence of the musical spectrum of each individual instrument and diminished coherence of the musical ensemble.

Mechanical vibration is a displacement of a physical body from its “at rest” position in reaction to the energy wave presented from the vibrating source. Some of these waves are vertically oriented (floor-borne vibration sourced from the loudspeakers and air conditioning/heating systems plus sympathetic vibration of the shelf directly under the component as it is excited by air-borne vibration) and some of the waves are horizontally oriented (air-borne vibration and the majority of the vibration sourced from exterior traffic and geological seismic activity). Furthermore, some of these waves are a combination of both. In addition, the horizontally oriented waves do not only come from one direction – they enter the system from a number of different vectors.

Clearly, comprehensively addressing vibration will take much more than simply placing a few feet or a single slab of material under a component. Any vibration control product that does not take into account all of the above sources and forms of vibration will not adequately address the problem. In addition, it is critical that the vibration control device does not add any new problems that will affect the signal flowing through the component.

The beauty of the Big Rock as a vibration control device is in its elegance and straightforward effectiveness. When the Big Rock is implemented as I recommend it has very high mass and is extremely absorptive yet is not significantly compliant. A speaker cabinet placed on the Big Rock’s Plinth will not rock back and forth in reaction to the speaker’s drivers while a significant amount of unwanted stored energy will transfer out of the speaker cabinet and be dissipated in the sand bed – the “exit strategy” if you will. In addition, a Little Rock pod (a very high mass damping and absorption pod) placed on top of the cabinet will damp excessive resonance in the speaker cabinet, absorb unwanted stored energy as well as causing the speaker to be planted more firmly to the top of the Big Rock making the transfer of unwanted energy even more efficient. Our upper model Little Rocks also incorporate EMI (electro-magnetic interference) shielding which is important when they are used with electronic components.

For ultimate effectiveness the Big Rock / speaker/ Little Rock should be placed atop one of our multi-cell Air Mass pneumatic mounts which will effectively decouple all of the above from the floor. This will stop the speaker’s mechanical energy from entering the floor and traveling towards the system’s components. The speaker is also protected from the other floor-borne sources of vibration which can compromise its performance. When an electronic component is placed within an Air Mass / Big Rock / Little Rock combination it too is protected from floor-borne vibration as well as being critically damped from above and below while it is simultaneously in intimate contact with high absorption reservoirs from above and below which significantly minimizes the effects of air-borne and internally generated vibration.

This vibration control system places the highly absorptive energy reservoirs in direct and intimate contact with the speaker or component. The transfer of energy from the component and its conversion to benign thermal energy is immediate and very efficient without any intermediate structures.

Another virtue of the Air Mass / Big Rock / Little Rock combination is that it is very resistant to horizontal displacement because of its extremely high mass. Is also has a resonant frequency in the horizontal plane as low as 2.5 Hz and 1.5 Hz in the vertical plane.

Vibration control devices that employ rigid coupling as the principal method of execution require the mechanical energy to go through a number of structures before it can leave the locale of the components. They typically claim to route the energy into the floor but unfortunately the floor does not readily dissipate mechanical vibration. If it did, the vibration would not be entering the component’s feet in the first place and we wouldn't even be discussing the need for vibration control. Moreover, the floor is one of the primary SOURCES of the destructive vibration!

Merely placing a vibration control device under a component does not address air-borne or internally generated vibration. Even if the device below the component does route some unwanted energy out of the component it can only do so AFTER the vibration and resonance have had time to degrade the signal flowing through the component. How far does the horse have to be out of the barn before the door is closed? No amount of “draining” after the fact will restore the signal to its original, pristine state.

It is also extremely critical that the vibration control device not add any of its own degradations to the signal flowing through the component. Employing materials that ring (metal, glass, stone, etc.) or materials that are resonant (wood, acrylic, etc.) will virtually guarantee that they will affect the signal and restrict the ability of the system to faithfully reproduce what is contained in the recording.

The fact is that making ANY change to a system will result in a change in the way that system reproduces sound. Even moving the location of the equipment rack by just a few inches in any direction will alter how the various pressure zones in the room will interact with the various resonance frequencies and resonance characteristics of the equipment resulting in change in the sound of the system. Moreover, changing the support under a component will usually cause a significant change in performance. Most audiophiles simply listen to the difference and try to decide if it is "better" or not. There is some merit in that method but I believe that controlling vibration should have the goal of allowing the system to more faithfully reproduce the sound of the original musical instrument as it has been captured in the recording. That can only be accomplished when contaminating vibration is minimized as much as possible in the audio or home theater system.

In many cases, simply adding or changing a vibration control device will not give the full indication of whether the change brings the system closer to my stated goal or not. Trying to “balance off” or “tune” resonances within a system may be an interesting pursuit, it will not allow that system to faithfully reproduce the sound of the instrument as it has been captured in the recording. In some cases when contaminating vibration is eliminated it will more clearly expose the true nature of the system by letting one hear all of the previous choices of components, set up and applied accessories. If those choices were made while the system was being plagued by destructive vibration (which describes virtually all systems until a comprehensively designed vibration control system is employed) the devices and set up already in place may no longer be appropriate once the problem of vibration eliminated. If the change is simply compensating for a deficiency or problem elsewhere in the system the listener may reach an erroneous conclusion about the efficacy of the change.

Tom, please let me know if you have any questions.

Best Regards,

Why change form? Are there no losses in conversion? If you let it vibrate, like it will do anyway, no matter what and you provide a efficient path way for vibration to exit would there not be be less loss than high mass dampening? Some coupling devices have a geometric bandpass at 4hz and below to reject the incoming at the point tip..Best Regards ..Tom
Hi Tom,

Tom asks: "Are there no losses in conversion?"

Converting to what?

If you are asking about the conversion from mechanical energy to thermal energy in the vibration control system I described the answer is yes, there is a great deal of loss which is the objective.

"If you let it vibrate, like it will do anyway, no matter what and you provide a efficient path way for vibration to exit would there not be be less loss than high mass dampening?"

You are right. There is LESS loss of mechanical energy when coupling is employed. What we want is MORE loss of energy so that it will have less effect on the signal that is flowing thorough the component.

"Some coupling devices have a geometric bandpass at 4hz and below to reject the incoming at the point tip"

Which coupling products manufactured for audio systems have resonant frequency and bandpass at 4Hz and below? Are there measurements to show this?

Please let me know if I had understood your questions correctly.

Best Regards,

So this must be why when someone runs next to me on the beach, I can feel his pounding footsteps in the sand under me.
TWL, Maybe its because the sand is wet? Did you consider that. Your friend should loose some weight, for his health sake, if nothing else. :-)

BTW when you and Tom are asking these kind of questions and/or making observations about a competitors products, don't you think it would be fair for you and Tom to once again identify for the uninitiated who your employer is and/or what products you sell?
Ok, I'm an employee of Starsound Technologies, and I asked the question about the sand.

Actually, I felt that I was being remarkably silent, considering all that was being stated here.

Truthfully, the reason why I was(and still am) at a loss for words here, is that I wouldn't even know where to start addressing all of the things mentioned on this thread, except to say that I'm not in agreement with hardly any of them.

I'm just letting the guy say what he wants to say.
I work for myself and for my clients. I sell products that I own myself, some of them are sourced from Starsound.Tom
TWL I was the one who started this thread and I would love to hear what your ideas are on vibration control. No need to response to Barry or others point by point, rather just give your feelings on the best way the deal with 185 lbs speakers on woood floor to get the best sound.
Hi All,

Anyone interested can see laboratory measurements of a speaker system with and without the vibration control system I described.

Here is the link:



Figure 1 shows the frequency response of a speaker without the vibration control system (red line) and the same speaker with the vibration control system I described (black line). You will notice a significant increase in response with the vibration control system.

Figure 2 shows a Cumulative Spectral Decay (waterfall) response of the speaker that is not placed in the vibration control system. Note the significant amount of vibration residue the speaker exhibits. This is vibration and resonance that is absorbed and released by the cabinet walls after the drivers have stopped producing the original signal. The extra "ghost" signal not only significantly colors the music it also produces random out-of-phase elements which affect imaging, soundstage abilities and transient response.

Figure 3 shows the same speaker that has been placed within the vibration control system. You will note that there is far less extra residue present in the speaker system and the graph looks much "cleaner". The extra energy that had been wasted making the cabinet vibrate is now being used to create more music - increasing efficiency and performance in all areas.

Figure 4 shows the same two waterfall graphs together
so you can more easily see the differences.

Please let me know if you have any questions.

Best Regards,

Without being argumentative about anything, I'd simply(and predictably) recommend trying a set of Audiopoints under your speakers, and compare them to the BrightStar stuff, or whatever you like, and let the winner dictate the purchase. If you need to protect the wood floor from the sharp points, we offer "Coupling discs" which will do the job.

We, at Starsound, offer a 30-day money back guarantee of satisfaction, with no questions asked if you don't keep them. Full refund, except for the $7.50 Priority mailing cost.

I'd like to compliment Barry on his availability of scientific charts showing the effects of his vibration control system. It was not clear which product was tested there, but it is a very nice display of the fact that vibration control has definite effects that are measurable.

Unhappily, I cannot produce any test charts for our products. But, our products have received awards for performance from publications who tested them, and we have an excellent consumer acceptance over 16 years of producing the same unchanged product(Audiopoints). We rely on the consumer's ear to determine what is best for their application.

Regarding my point-of-view on resonance control, I adhere to the "Resonance Energy Transfer" approach, which provides an "escape path" for the vibrational energy to be routed to ground and dissipated there, instead of the "local damping" methods described by Barry above. Each method has its proponents, and both methods can be effective to various degrees, but may have different sonic effects due to the technologies employed.

Some people may prefer one type, while others prefer the alternative. For example, I just took in a Bright Star Rack of Gibraltar(top of the line product) on trade toward our Sistrum SP-4 from a customer, and he proclaimed "no contest, the SP-4 was the clear winner". Doubtless, Barry has had similar experiences where his rack proved out to be a winner.

So, as you can see, there are differing opinions on this subject, about what works best in different applications, and sounds best to people with different listening tastes.

We simply provide a way for the customers to test in their own homes, to see what they like best. We feel that is a fair way to do things, and it lets the customer be the judge. We put our "money where our mouth is" with every single customer, because everything we make has the money-back guarantee of satisfaction, lifetime warrantee(transferable), and we have 16 years of track record to back it up.

Nobody ever "gets stuck" with a Starsound product. If you don't like it, for any reason, we take it back for a full refund within 30 days(less shipping).

Again, I'm not trying to cause dissention here, just presenting my point-of-view as a manufacturer's rep, and letting the chips fall where they may. Please feel free to email me with any questions, or to discuss.
As long as the evaluation includes the complete vibration control system I described above I would also welcome a comparison.

I would also like to say that I have nothing against Tom, either personally or professionally. I do not know him and I do not believe we have ever met in person. He seems like a very nice guy and I know he has been helpful to many Audiogon members in a number of different areas which makes him an asset to the audiophile community.

I do feel, however, that there is a general lack of thorough discussion on the internet and in many audiophile publications on the subject of vibration control. Typically, there is a trial and error methodology that is used by most audiophiles and is also sometimes recommended by manufacturers and dealers – add the device to your system and see if you like it or not. We live in free society so no one can tell another person what they like or don’t like (and, of course, people should like how their systems sound), but this haphazard manner of evaluation is fraught with difficulty and many times leads to erroneous conclusions.

I think that we would all be well served by the introduction of more science and more stringent evaluation to the category of vibration control. This will advance the state of the art of audio reproduction. The most important issue is to understand the nature of vibration, how it affects the components within our systems and ultimately, how well the devices, materials and methods that are used address those issues.

Best Regards,

Barry Kohan
Barry, I agree with you, and I'm really pleased to see that you have some testing charts and other documentation to help people understand the need for vibration management in their audio and video systems.

I always read your posts, and I also feel that you are a valuable and welcome member in the audiophile community.

Anytime more solid information comes into the public view, it is better for all of us concerned.

Even though we compete in a way, for certain segments of the market, we are both advancing the position of vibration management systems in the audiophile world.

We're working on getting some impartial 3rd party scientific testing on our products done at a major engineering university, and when we get the results, I'll be sure to make them public.
Barry is there any information on the speed or rate of vibrational dissapation of materials such as those in your designs versus the reloading or buildup of vibrational resonance in a typical stand alone audio component..Tom ..I sell audio and video products, some are sourced from Starsound..