Speaker Spike Philosophy


This is a learning exercise for me.

I am a mechanics practitioner by training and by occupation, so I understand Newton’s Laws and structural mechanics and have a fairly effective BS-detector.

THE FOLLOWING THINGS PUZZLE ME, and I would be glad to hear from those who believe they understand so long as the responses are based on your actual experience or on sound mechanical arguments (or are labeled as conjecture). These are independent questions/musings, so feel free to weigh in on whichever ones you want, but please list the number(s) to which you are responding:

  1. Everything I have read recently ("Ask Richard" (Vandersteen) from 15 Feb, 2020, for instance) seems to indicate that the reason for speaker spikes is to hold the speaker fixed against movement induced by the drivers. I have seen in the past other explanations, most employing some use of the term "isolation" implying that they decouple the speaker (from what?) Evidently the "what?" is a floor that is fixed and not moving (let’s assume concrete slab foundation). So to decouple the speaker from the floor, which is fixed, is to . . . allow it to move (or not) as it wishes, (presumably in response to its drivers). These two objectives, "fixity" and "isolation" appear to me to be diametrically opposed to one another. Is the supposed function of spikes to couple the speaker to "fixed ground" so they don’t move, or is it to provide mechanical isolation so that they can move (which I do not think spikes actually do)? Or, is it to somehow provide some sort of "acoustic isolation" having to do with having some free space under the speaker? Regarding the mechanical isolation idea, I saw a treatment of this here: https://ledgernote.com/blog/q-and-a/speaker-spikes/ that seemed plausible until I got to the sentence, "The tip of a sphere or cone is so tiny that no vibration with a long waveform and high amplitude can pass through it." If you have a spike that is dug into a floor, I believe it will be capable of passing exactly this type of waveform. I also was skeptical of the author’s distinction between *speaker stand* spikes (meant to couple) and *speaker* spikes (meant to isolate/decouple, flying in the face of Richard Vandersteen’s explanation). Perhaps I am missing something, but my BS-detector was starting to resonate.
  2. Spikes on the bottoms of stands that support bookshelf speakers. The spikes may keep the the base of the stand quite still, but the primary mode of motion of such speakers in the plane of driver motion will be to rock forward and backward, pivoting about the base of the stand, and the spikes will do nothing about this that is not already done by the stand base without spikes. I have a hard time seeing these spikes as providing any value other than, if used on carpet, to get down to the floor beneath and add real stability to an otherwise unstable arrangement. (This is not a sound quality issue, but a serviceability and safety issue, especially if little ones are about.)
  3. I have a hard time believing that massive floor standers made of thick MDF/HDF/etc. and heavy magnets can be pushed around a meaningful amount by any speaker driver, spikes or no. (Only Rigid-body modes are in view here--I am not talking about cabinet flexing modes, which spikes will do nothing about) "It’s a simple question of weight (mass) ratios." (a la Holy Grail) "An 8-ounce speaker cone cannot push around a 100/200-lb speaker" (by a meaningful amount, and yes, I know that the air pressure loading on the cone comes into play as well; I stand by my skepticism). And I am skeptical that the amount of pushing around that does occur will be affected meaningfully by spikes or lack thereof. Furthermore, for tower speakers, there are overturning modes of motion (rocking) created by the driver forces that are not at all affected by the presence of spikes (similar to Item 1 above).
  4. Let’s assume I am wrong (happens all the time), and the speaker does need to be held in place. The use of feet that protect hardwood floors from spikes (Linn Skeets, etc.) seems counterproductive toward this end. If the point of spikes is to anchor the speaker laterally (they certainly do not do so vertically), then putting something under the spikes that keep the spikes from digging in (i.e., doing their supposed job) appears to defeat the whole value proposition of spikes in the first place. I have been told how much easier it is to position speakers on hardwood floors with the Skeets in place, because the speakers can be moved much more easily. I was thinking to myself, "yes, this is self-evident, and you have just taken away any benefit of the spikes unless you remove the Skeets once the speakers are located."
  5. I am making new, thick, hard-rock maple bases for my AV 5140s (lovely speakers in every sense), and I will probably bolt them to the bottom of the speakers using the female threaded inserts already provided on the bottoms of the speakers, and I will probably put threaded inserts into the bottom of my bases so they can be used with the Linn-provided spikes, and I have already ordered Skeets (they were a not even a blip on the radar compared to the Akurate Exaktbox-i and Akurate Hub that were part of the same order), and I will end up doing whatever sounds best to me. Still, I am curious about the mechanics of it all...Interested to hear informed, reasoned, and reasonable responses.
linnvolk
bachemar,
Imagine you are an audiophile. No, wait, too hard. Nevermind.

@millercarbon I’m really curious as to why it would be so hard?  Is it the rational and common sense approach to understanding the impact of various footers on vibration suppression is too hard to comprehend?

Or could it be, because I called out that your preferred method - Springs, are you know.. “springy”, and would not be be best at damping vibrations.  The spring action would just add their own color or even potentially, resonance to the vibration. Springs might be good at suppressing vibration transmission (from one send to the other), but this is a different application altogether. 
@mitch2 - The R500s weigh 48 lbs and the discs are 1square inch (1.125 inch diameter)) with 4 spikes, so 12 psi if you assume the force is evenly distributed throughout the bottom of the disc, which is not possible as the disc gets thicker as you get near its center where the spike fits. If you assume the part hitting the floor with force is the size of the indentation, then you are talking about an area of .0128 sq. Inches (.25” diameter) for a force of 937 psi.

I would argue the area is even smaller, about the size of the tip of the spike which I can’t measure without lifting the speaker, which I am not going to do. Let’s assume it is 1/3 the size of the indentation (it’s probably less) so diameter is .0833” for a force of 2200 psi or 317K psf!

I am sure digging the spike into the floor would be better sounding (not sure by how much), but grinding up up oak floor is a non starter. The way I have it probably sounds better than if I had the spike digging into carpeting that has padding under it.

in any case, I am sure that if I had my 4 discs sitting on top of a Townshend platform, the sound would improve (I have one under my turntable and it was an incredible improvement, but my 10 lb table is a lot more susceptible to vibrations than my speakers are). However, the platforms cost more than my speakers (after close out discount) - so that’s a non-starter.

in the cost no object world some posters reside, around $2K for speaker platforms is a rounding error, but for us regular guys with low 5 figure systems, it is substantial. That being said, $10K+ speakers should include stands that optimize their sound or build it into their cabinet designs live Vivids and KEFs do.
Great discussion.

Wilson Yvettes, 160 lbs, very inert cabinet, ceramic tile over concrete floor. Wilson recommends their own spike, which I upgraded.

What I’ve learned here is that everyone’s situation is different. As my friend Bill at Wilson says... yes you will hear a difference with GAIA footers... but is it better? You decide. He does this every day. I tried expensive Stillpoint footers. Unlike many Wilson users, I didn’t care for them. They guys that swear by them usually have speakers two or three times heavier than mine. Over what flooring? The Yvette speakers are now off the Tile and on heavy carpet with the spikes so no discs. Sounds is best yet. JL Audio f113 sub sits on a heavy symposium platform on GAIA footers. Sounds great, had to turn it down a bit. Getting it up off the floor helped. My recommendations, as many here are likely of only moderate use to you as we each have very different speakers, floors and rooms. And haven’t tried everything. Once again, our ears are the best judge. A fun topic to experiment with though. Have fun and Happy Easter!
Wow,just reading this post will wear you out,let alone trying half of these things.Save yourself a lot of time,energy,and hassle,and just go buy 8 Stillpoint Ultra 5’s. They are reasonably priced,easy to install,solves 99 percent of anyone’s problems,sound beautiful,and look beautiful. I’ve had them under a set of Focal Scala Utopia V2 lll’s for over five years.The house is on a cement slab and I couldn’t be happier.From the minute they were installed,the music became more detailed and better in every aspect.I am amazed at the lengths people go to trying to address such an easy fix.   John
sokogear - assuming the steel disc is rigid and doesn't deflect, the stress will be spread uniformly over the area of the disc.  That is how structures work, like a column load being supported by a square footing, and is why they use discs in the first place - to spread the load out so the spike doesn't poke or dent the floor.  If the disc is not exactly rigid (although I believe they are), then the load will be somewhat higher under the concentrated point.  You are correct though that it is a lot of load over a small area.  If I were to support my 180-pound speaker/stand assembly on four 18mm diameter discs, the resulting pressure under the discs would be over 100 psi or over 16K psf, so maybe that couples the speaker....I don't know.
MIllercarbon,  Is your listening room floor concrete slab on grade or wood frame?
I would think decoupling would be more effective on a lower mass / lower stiffness floor. Curious if your significant improvement with Townsend podiums is applicable to slab on grade. 
bachemar-
Imagine if you (speaker) were trying on different types of mattresses (footers) and were wriggling in place (speaker vibration) and how the mattress felt. Now imagine different types of mattresses and what exactly would happen to your wriggling efforts
  1. Cheap spring mattress, where you can feel the springs - The springs would absorb some of your wriggling, but it would still feel uncomfortable, because you can feel the "springiness" of the springs. This springiness is really the springs bouncing back from your wriggling but with a slight time delay.
  2. You now add a pillowtop to the spring mattress (the Damping that was mentioned in an earlier post) - Ah much more comfortable, the pillowtop absorbs some of the low amplitude wriggling, and also absorbs some of the spring feedback, so it feels less bouncy
  3. An old school (non memory) foam mattress - slightly better, but still suffers from the springiness, although to a lesser extent
  4. You now try on a memory foam mattress (sorbothane, Herbie's discs etc.). There's no more force feedback from the mattress, and the memory foam, helps absorb and dampen your wriggling
  5. Sleep on the floor or a block of wood/stone/marble etc. that is lying on the floor - This would be fairly uncomfortable, the floor does nothing to absorb the wriggling, but doesn't impede it either. As you wriggle, you create multiple contact points between body and floor, which could create its own rattling sound.
  6. Now imagine if your skin was rigid, and had built spikes attached to your back, sleeping and wriggling on a concrete/stone floor - Similar to above, but the spikes might reduce the contact points making it slightly harder to wriggle and much more reduced rattling noise
  7. Now imagine sleeping with built in spikes, but these spikes have dug into the wooden floor - I imagine, the bonding of the spike with floor would create a damping effect making it harder for you to wriggle
bachemar,
Imagine you are an audiophile. No, wait, too hard. Nevermind.
you laugh but when I visited Solid State Logic’s recording studio just north of Oxford in the early 80s the reference monitors were suspended from the ceiling

I too have seen speakers suspended from the ceiling with chains in a medieval dungeon styie arrangement. Sounded excellent.
My Experience over the years dealing with 
speaker spikes are only good for wood 
floors.Concrete floors make your speakers 
sounds lean.
@audiopoint , That was a rather long winded dissertation. Although I believe there are resonance points at higher frequencies involving drivers, parts of drivers and speaker enclosures, the ones that are clearly audible and measurable by simple methods reside in the bass frequency range and are most difficult to control in subwoofers because of the mass of the drivers, the amount of air that has to be compressed on both sides of the driver transferring a lot of energy to both the environment and the enclosure. Subwoofers clearly shake in the direction the driver is moving which as I have shown can be measured with an accelerometer. Spiking the subwoofer clearly reduces this shaking/resonance because the mass of the loudspeaker is now fixed to a much larger mass. If you want to say that the resonance is drained away by the floor and house that is fine by me. Subwoofer enclosures also resonate in other ways but the big one besides shaking is expanding and contracting from the pressure differentials within the enclosure. Again this is easy to measure and clearly audible. This one is more difficult to deal with and requires some design cleverness. The frequencies at which these resonances occur depends on a number of physical factors like this stiffness and size of the enclosure walls and the overall mass of the enclosure. Any resonance in a speaker enclosure at any frequency is distortion whether or not it is audible is a different question. A subwoofer measurably generates less distortion when it is firmly spiked to the floor. I do not know if this is true for a full range loudspeaker that is crossed to a sub at say 100 Hz. At higher frequencies not near as much energy is transferred to the environment or the enclosure. Does vibration transferred to a purely electronic device cause audible distortion? I seriously doubt it but neither have I run that experiment so in truth I have to say I do not know.
Designing a decent speaker spike is child's play as is making a decent speaker stand. Locking the speaker to the stand is also child's play as long as you don't mind sinking a few screws into the enclosure. Designing and making a subwoofer enclosure that does not shake or resonate is not so easy. Do you have any siggestions?
Might be easier to imagine the effects of different options (springs, spikes, sorbothane etc) by comparing it to something we can all relate to - Mattress shopping.

Imagine if you (speaker) were trying on different types of mattresses (footers) and were wriggling in place (speaker vibration) and how the mattress felt. Now imagine different types of mattresses and what exactly would happen to your wriggling efforts
  1. Cheap spring mattress, where you can feel the springs - The springs would absorb some of your wriggling, but it would still feel uncomfortable, because you can feel the "springiness" of the springs. This springiness is really the springs bouncing back from your wriggling but with a slight time delay. 
  2. You now add a pillowtop to the spring mattress (the Damping that was mentioned in an earlier post) - Ah much more comfortable, the pillowtop absorbs some of the low amplitude wriggling, and also absorbs some of the spring feedback, so it feels less bouncy
  3. An old school (non memory) foam mattress - slightly better, but still suffers from the springiness, although to a lesser extent
  4. You now try on a memory foam mattress (sorbothane, Herbie's discs etc.). There's no more force feedback from the mattress, and the memory foam, helps absorb and dampen your wriggling
  5. Sleep on the floor or a block of wood/stone/marble etc. that is lying on the floor - This would be fairly uncomfortable, the floor does nothing to absorb the wriggling, but doesn't impede it either. As you wriggle, you create multiple contact points between body and floor, which could create its own rattling sound.
  6. Now imagine if your skin was rigid, and had built spikes attached to your back, sleeping and wriggling on a concrete/stone floor - Similar to above, but the spikes might reduce the contact points making it slightly harder to wriggle and much more reduced rattling noise
  7. Now imagine sleeping with built in spikes, but these spikes have dug into the wooden floor - I imagine, the bonding of the spike with floor would create a damping effect making it harder for you to wriggle
mitch2 - I'm talking about the tip of the spike going into a tiny indentation in the middle of the disc which is where it reacts with the floor. The weight of the speaker will go through that small area, not the entire disc because that is where the force is concentrated.
Discs under spikes are probably as close to decoupling as to coupling.  The KEF discs are 18mm in diameter or about 250 mm squared in area, which is probably about 100 times the area of the tip of a spike.
See what the speaker manufacturer recommends. Some come with stands or spikes or some nothing at all, and some with options (not sure why floor standers would come with options).

KEF floorstanders have a nice set up - extended arms screwed into the speakers that have spikes screwed into their underside which can go into carpet. Takes a little while to install them. For hardwood floors, there are discs that come with that have extremely small indentations where the very end of the spikes fit so they floors don't get gouged and you can carefully move the speakers for ideal positioning without scratching the floors. They design their speakers around being a couple inches off the floor. Simple reason....that's how they sound best. Don't overthink it. They are tested over and over.

The discs don't defeat the purpose of the spikes because the tiny area with the force touching the floor is only very slightly larger that the tip of the spike.
@chris_w_uk you laugh but when I visited Solid State Logic's recording studio just north of Oxford in the early 80s the reference monitors were suspended from the ceiling exactly like that with a single sheet of kleenex hanging a few inches in front of the tweeter
If you ever get the chance, have a listen to a good pair of speakers with spikes/cones under them. Then try some Townshend Podiums. Once you pick your jaw up off the ground and finish asking yourself why life is so cruel, I think you might make some paradigm shifts in your thinking.

If you are really cash strapped, don‘t.
I’m using custom made atacama stands for my tannoy eatons...the only reason I have spikes installed on the bottom of the stands is to puncture the carpet to make contact with the concrete slab below. The stands are rock steady and filled with atabites. Otherwise, I use a pea sized blob of blue tac on each speaker corner between speaker and stand. I also make a habit of placing a decorative object on top of each speaker. I feel that it helps disperse and absorb cabinet vibration, plus it looks good 😁.
I also do not elevate my speaker cables because I believe it to be bunk. I try not to be bothered by the possibility of seismic vibrations, also ridiculous. Just my opinion🤪.

@linnvolk - that pressure inside the enclosure, with respects to the enclosure's mode/s will color the music.
It is my best guess to explain the superior sound stage and clarity afforded by isolation, that while the enclosure is flexing, the center of gravity remains more stationary, while everything else flexes and vibrates.

I have heard speakers with an isolated second baffle, where the outer baffle is where the reflections off the drivers are made, and it was very very good.
Has anyone else considered that the area of the driver creating the sound pressure wave also meets with resistance from the air it's moving, both inside and outside of the enclosure (assuming it is used in such a fashion).
@rixthetrick, yes.  See OP Item 3.
Has anyone else considered that the area of the driver creating the sound pressure wave also meets with resistance from the air it's moving, both inside and outside of the enclosure (assuming it is used in such a fashion).
Therefore it's not just the moving mass, it's also the back pressure from air resistance that can be taken into account??

Regardless, I have not heard speakers sound better than by effective decoupling in union with a tuned mass damping.

Unfortunately it is an economic compromise between mass and cost of logistics to ship and store loudspeakers. Mass is a great way to dampen, however mechanical engineering has evolved to the point where seismic devices are proven to be more effective, than trying to rigidly maintain integrity.

I do understand the skepticism to move away from traditional methods of loudspeaker mounting, however, having been exposed to newer technologies, there simply is no going back for me.

Spikes only detract from the potential of a well built and designed speakers performance. Your goal is to decouple the speakers from the acoustics of the room, so you are listening to the drivers only as far as possible. The best way to do that is to use Norm Varney’s (AV Room Service) EVP decouplers. Very well priced when compared to the result. The EVP decouple your speakers from the room. Adding the EVP units under my speakers was one of the best bang for the buck upgrades if you are looking for a system that portrays the original recording the correct timbre and dynamics of a recording. Sharpened the mid bass all the way down to the lowest octaves. My system is capable of imaging to a much lower frequency with the EVP’s. Simply amazing

The creative questions presented by the OP are not capable of two sentence explanations. I attempted to keep more of the interesting facts and opinions in full view asking for your patience involving the length of read.

To linnvolk, in reply to your original post:

Generic Spikes are the problem!

Line item 1: Spikes cannot be defined or grouped into a single topic as no two designs are manufactured the same nor contain the same material-science or shape, therefore will not function in the same manner. This is true for spheres and springs and any other footer materials used in audio. Some cost a couple dollars where others are priced in the hundreds so which one should be used as the principal focus for topic discussion?

Disclaimer: I represent a thirty-two-year-old spike design that has earned a reputation in High-End Audio for delivering performance managing the musical characteristics known as attack, sustain and decays. We also manufacture platforms for floor standing speakers.

There are a lot of opinions focused on eliminating vibration on this forum. They are all based on theorems. In fact, “all methods of vibration management” are based on theorems, so it is easy to see that most listeners have a favorite of their own or have created a theory for themselves and that is a good thing as this is how Industry grows.


The only thing that all spikes have in common is they ‘mechanically ground’ a device to the greater energy sink in the environment. A spike can be defined as a mechanical resonance conductive conduit. An energy sink can be defined as the greater mass - of a floor, wall or room structure or earth’s ground itself.

Physics dictates all energy seeks earth’s ground and will transfer there via the path of least resistance.

In audio, spikes deliver a wide variety of speeds of resonance energy transfer which greatly affects the frequencies of the device being mechanically grounded. The material used to make spikes, their mass and body shapes are paramount to the overall function and sonic result of a spike.

Driver and chassis movement:

In my opinion, speaker cone movement related to chassis movement is a widening gate for arguments and subjectivity. There is no “live test” for speaker dispersion, meaning a driver could be firing a ninety-degree vertical spread on the left side and a sixty-degree horizontal spread on the right and no way to prove otherwise in a live dynamic environment.

 The first response to that statement is the anechoic test. Anechoic is a vacuum environment designed to tear away and absorb all energy including vibration, resonance and the laminar flows of energy seeking earth’s ground. We take computer generated readings and images to “show” the drivers are firing in the round then end up placing the speaker into a “live environment” where the laws of gravity, motion and Coulomb’s friction are ever present disrupting the anechoic test results. Then again, data is important so any type of test benefits education.

Speaker movement and chassis movement are minimalist concerns when the speaker system is mechanically grounded. In all my days of listening as a sound engineer and commercial sound consultant to the music lover and avid audiophile, there was never a time where I have been able to blame speaker cone movement related to chassis movement as a negative factor when encountering poorer sound quality. Or maybe I cannot tell or do not know if infinitesimal movement is audible.

My focus is audibility. Inaudibility delivers more questions and makes things more difficult to prove although inaudible noise plays a factor in the overall system sound, sound-staging, pressure levels and room sonic.


I wish audio companies could afford or would desire to establish third party testing methodologies backed with written opinions by our peers, hence quantifying the results. The larger more financially outfitted companies obviously avoid that type of research and would rather spend their dollars on marketing and product reviews. I also believe audio is too ‘humanly subjective’ for most sciences and/or third-party options.

We were involved in third party testing using temperature as our control factor. In our case mechanical grounding not only reduces noise but heat as well. Temperature reduction is more attractive to science in comparison to sound reproduction. Covid put a long delay on that project.

 

Line item 2: What most listeners and Industry reviewers and speaker designers fail to realize is the magnitude of sound quality that is missing due to the physical speaker-to-stand-to-floor relationship. 

A speaker stand plays the ultimate role in the overall sound performance of any compact monitor. The method in which the speaker is placed or mounted to the stand is extremely important as well. Ten thousand dollars spent on a pair of speakers with a six or seven-hundred dollar set of stands does not make for the best sonic performance from your financial investment.

The majority of speaker-stands in today’s marketplace lacks engineering and purpose other than they are a place to set your speaker on top. Too many variables one of which is my pet peeve… fill the legs with what kind of material and how much fill do I use? You might think the engineers in charge of the design would have done a lot of listening tests and figured that one out by now.

As for the lifestyle issues involving stability and children, we must first come up with a great stand then adapt a secure universal mounting system to hold the speaker without changing the sonic character of the speaker system.


Line item 3: Our platforms contain spikes and are designed to vibrate which is a form of movement. This motion is absolute minimalist. The artifacts caused by motion that a laser might determine are a moot point in comparison to using vibration as a tool to improve the physical operational efficiency of the device.


Increased component operational efficiency is attainable provided the mechanical grounding plane (the platform) transfers resonance at or as close to as possible, the speed of which resonance is being formed.  


The methodology of resonance transfer also works with electronics as these platforms are based on physics, material science and geometry. It does not matter what is placed on them (speakers, electronics, power distribution, compressors, fan motors, etc.) as the design is engineered for function. In addition, this system allows for weight tolerances in the thousands of pounds eliminating those issues.

In music reproduction, everything vibrates (movement) and has high-speed relationships beginning with the throat or musical instrument to the microphone diaphragm to the recording drives to the pre/post-production equipment to the structural environment and finally the human eardrum itself. Mechanical grounding is designed for rapid resonance energy transfer processes hence the timing relationship is formed.

 Vibrations create the REAL PROBLEM and that is RESONANCE.

Resonance is caused by many vibrations where amplitudes of resonance clog all signal pathways – mechanical, electro-mechanical and acoustic. The problem is those initial vibrations contain the dynamics and harmonic layers we seek to hear so one must capture those highly favorable features and avoid resonance buildup and in real time.

How does one manage resonance? Our preferred methodology is to transfer the resonance to the greater sink or mass in the environment.

This is where the isolation group has difficulty explaining their theories as isolation techniques hold resonance within the component or speaker system establishing operational inefficiencies.

Resonance without a rapid evacuation gateway will build and cling to and propagate on all smooth surfaces from transistors to large speaker chassis establishing operational inefficiencies. In essence, the equipment becomes a resonance capacitor – per the Laws of Coulomb.

The difference between a highly effective isolation system and resonance transfer system of near equal financial value is extremely audible and can be blind tested employing multiple listeners. Both isolation and transfer systems provide function, but the sonic results are quite different.


Line item 4 I do not want to stop your construction experiment using maple foundations but will inform you what to expect from this design approach and outcome.

Wood vibrates and establishes a lot of additional audible frequencies. These frequencies will influence everything in your system’s performance from electronics to acoustics. Proof of wood sonics are discussed many times on this forum. For years you read particle board sounds OK, hardened maple sounds better than butcher block, exotic hardwood species sound even better, etc. 

Wood also remains in a constant state of change and movement due to humidity factors so your audible point of sonic reference may also change daily along with the sonics wood produces regardless of mass or thickness.

Bolting the wood sections directly to your speaker will marry the plinth to the chassis so they will react as a single unit. You will increase the chassis mass and therefore alter the sound of your speaker – guaranteed. You may like or dislike the change, but the original speaker designer usually ends up becoming the unhappiest person involved in this experiment.

Then there is the mechanical grounding process where the “spikes” will control the result of the experiment. A poorly designed spike equals poorer performance and that we can attest to after working thirty years in the vibration management field.


A form of acoustic coupling is placing a speaker directly on a floor without separation of any kind between the two planes. The speaker now assumes the floor mass as being part of its design whereas the woofer/s generally overextends to compensate for the added mass. In the case of using a carpet membrane between the two, carpeting generally has rubber or foam in the mix where these primary adsorbent materials greatly limit the speaker’s dynamics and sound quality.

Acoustic coupling is not recommended by hi-fi speaker manufacturers as it results in sonic degradation. The industry needed an answer to this problem so early on, back in the sixties, the easiest and most affordable fix or add on accessory became the nail head spike or rubber footer. Both parts limit sound quality but still remain extremely affordable!

Years ago, prior to flying and mechanical grounding commercial sound systems to the ceiling grids, we stacked the speaker cabinets on the floor or stage so the ports would be parallel stacked or positioned side by side each other hence increasing the sonic output by 1.5dB. The coupled ports reinforced the air pressure exiting the system. This too was referred to as acoustic coupling.

Regards to surface protection discs, discs machined of metal, wood or any material lacking geometry degrades spike performance. We have spent years listening, prototyping and listening again to establish a highly functional Coupling Disc. The design was created to function specifically with our products but is known to increase the sonic of others. I cannot and will not attest to anything other than performances related to our specific products. Coupling Discs appear to be simplistic in cosmetic look but there is more engineering and time spent on development than most of our spike designs. The geometry is used for speed and time matching resonance flows from the spike or platform and energy distribution across the flooring surface.


Too much emphasis is placed on simplistic two-dollar parts that literally drive “High-End Audio” conversations, theorem evaluations and product comparisons in today’s modern market. Think about it?


Thank you for your time,

Robert

Disclaimer #2: This information is not written to increase sales nor are we shilling this site for business purposes despite some members consistently analyzing my participation as being of an advertising nature.

It is most difficult to provide information on a new technical approach opposite that of long believed old school methodologies when the products themselves become the determining factual evidence of proof and function.



I run the Gaia footers with very good affect under my ATC 40 actives.  I just followed through this morning with a menagerie of allen wrenches and star pieces to tighten up the driver component attachments to the cabinets.  I give credit to Tom, proprietor of Big Ear Stereo in Tempe, AZ for this suggestion.  

To my amazement several were less than tight.  And as one might surmise, everything just got better.  Uncontrolled vibration is found everywhere.
Post removed 
The speaker resonating in any way is distortion. Ideally you should be able to feel no vibration at all anywhere you put your hand on the enclosure except the driver.
I dont feel vibrations with my finger behind my speakers enclosure....Nor on my desk where the speakers are....

I feel and know that my dissymetric damping tuned load on 2 sets of springs under and over the speakers is very efficient, even if not perfect....  The increase of tonal timbre natural perception with a very well tuned set over the speaker and not only under it and under the optimal compressive force with 1% accuracy was a great improvement.... Cost for all 8 sets of springs for the 2 speakers 100 bucks...
When first bought, I did not use the spikes, they were on the base, on thick carpet.  They were not very solid

    Not sure about sound quality, but it did help with stability. And Keeping  the base just above the carpet may help with bass, not sure. 
    They do what they are supposed too do. 
Linnvolk, you are absolutely right. I shortened the explanation by saying,"minimizes some but not all of this." The speaker resonating in any way is distortion. Ideally you should be able to feel no vibration at all anywhere you put your hand on the enclosure except the driver. 

I build my own subwoofers, the design I am currently using focuses on high mass keeping the bulk of the mass behind the driver. They have rectangular enclosures 14"X16"X30" with the driver located in the end. They are made out of solid surface material and MDF. Each enclosure weights 200 lb without the driver a very massive 12" Dayton. Testing with an accelerometer indicated two modes of vibration back and forth along the main axis and expanding and contracting. Without the spikes the drivers also walked backwards on carpet. I think they went backwards because the rear bottom edge is radiused and the front edge which originally accommodated a grill is sharp and catches the carpet. Installing spikes obviously stopped the walking and almost entirely stopped the axial vibration and did nothing for the expanding/contacting resonance. Although these subs sound better than any other subwoofer I have used I consider them a failure and am in the process of building a new set. The new set uses a cylindrical enclosures with 12" drivers in both ends operating in phase. The walls average 1 7/16" thick. The forces from the drivers should cancel out and a cylinder is much stiffer than a rectangular cube. We shall see if this works, hopefully by the end of the Summer after I finish my wife's Kitchen.
@linnvolk - I agree - accelerometer data would be quite informative.
However, when a front-firing 100 lbs subwoofer is resting on springs with limited horizontal stability (because they are not guided by a shaft or control arms), you are not looking at a "rigid-body mode".
The woofer motor accelerates the membrane forward, and - assuming above numbers - generates a backward counter-impulse equal to a weight of 46 pounds (that's roughly equal to a force of 200 N - substantial). This definitely suffices to move the entire sub backwards when it is not fixated and can move horizontally. The effect is - as stated - very audible and can be measured in terms of reduced SPL. For any service arrangements, please negotiate with @ausaudio directly :-)
Here’s a link to I’ll talk to many of us had a couple years back. It’s funny to see who has change their views and who has not
This idea has been bounced around for a long time. Here’s the link to the question I asked the group a year or so ago. It’s pretty funny to read it and see who has changed their views. Here’s the link,https://forum.audiogon.com/discussions/what-your-choice-speakers-with-spikes-or-speakers-with-a-vibr...
Wow! This has been batted around for a long time. Here’s a link to the question I asked when I first joined the website. It’s funny to see how some guys have changed and some guys have not. I’m still All about springs. Check out the link it’s pretty funny.
https://forum.audiogon.com/discussions/what-your-choice-speakers-with-spikes-or-speakers-with-a-vibr...
@linnvolk - I can see that Accelerometer testing would be helpful. However, your operating assumption, “100 lbs in rigid body mode”, is exactly at issue here. Once you set the sub on springs you reduce horizontal stability significantly and can no longer assume rigid body mode.
You accelerate the membrane forward, and with a (g x mass) force of 46 pounds you will push the sub backwards, reducing the net amplitude, even against the inertia of a 100 lbs object.It is obviously audible and measurable in terms of SPL reduction.

I will say that spikes can help on wood floors to tame the bass a bit but putting blocks of stone under the speakers control the bass better and sound better too as far as a concrete floor i have not found a reason to use spikes or stone blocks or slabs under the speakers. Yes i believe that the claims of spikes can be far reaching especially for anything expensive.
Yeah, and paying for all the wasted time running down dead end rabbit holes. 

Probably the most important thing to keep in mind is the part of the signal that gives us our sense of exactly what instrument it is and exactly where it is coming from is exceedingly subtle, fine, and low in level. So low in level that even very fine vibrations are enough to blur and lose it. This is why things like fO.q tape work so well. This tape only damps micro-vibrations, but does this so well a very small amount produces a very noticeable improvement in midrange presence and detail. 

The same happens when ringing is eliminated by putting the speaker on springs. Townshend Podiums are the best springs because they also eliminate tonal coloration caused by resonant behavior. But however it is done springs are the best at this by far, simply because they are the best at uncoupling the speaker from the floor. 
@ausaudio, I agree with the light finger pressure at the upper back edge of the speaker, to ID rigid body rocking response.  As for rigid body translational response, the bottom of the speaker might be better.  I don't know though if we can conclude that what we feel in either location is free of flexural modes, though it ought to be more free than anywhere else on the speaker.  Best to place accelerometers at multiple places and post-process for modes; the rigid-body components should be easy to identify for an experienced dynamicist.  Glad you are paying for all this.
@aschuh, that would be quite true if the force were static.  In your example, that force is reversing direction 60 times per second.  No problem for an 8-oz woofer cone.  The displacement (vibration) response of the 100-lb sub in rigid-body mode at that frequency will be of very small magnitude as it is nowhere near the natural frequency for that mode.  Whether there is enough magnitude to matter and whether the magnitude is attenuated by the use of spikes or springs (and whether that attenuation is good, bad, or indifferent) IMHO would best be addressed by running the test and using your hands/ears...or accelerometers.  For the accelerometer testing, please hire my company, have them spend several days on testing (I will write the test report), and send @ausaudio the bill.
@ausaudio - At 92 g x 8 ounces mass you are looking at a force equal to a weight of 736 ounces or 46 pounds.
It is very possible that a horizontal force directed towards a 100 pound sub, sitting on springs with minimal horizontal stability, moves the sub horizontally.
I would suggest light pressure of a finger at the upper back edge of the speaker to detect movement as opposed to cabinet flex. Thoughts?
@ausaudio,

You caught me in some less-than-clear writing.

The second quote is based on a tacit assumption that we are talking about hard floors.  This is what I have, and I tend to default to it without necessarily giving the reader the appropriate cues.  My bad.  The point here is that putting spikes on a speaker that would otherwise be sitting directly on a hard floor does nothing to help the stabilize the speaker against the rocking mode.  They actually will destabilize this mode, because the spikes have to be inboard of the periphery of the speaker base in order to have something to screw into.  This reduces the footprint and thus the resistance to rocking.

The first quote addresses, as stated, the case of tower speakers on thick carpet.     It is equally or even more applicable to bookshelf speakers on stands (which are likely a more top-heavy arrangement). In this case, the speaker will want to rock back and forth on the springy carpet, pivoting about its base, due to the carpet's compressibility.  Here, using spikes lets you bridge across the mushy carpet and get "seated" on hard floor.

I agree with your accelerometer statement.  My life is not long enough nor my pockets deep enough to head down that road.  Though not part of my practice area, my company could actually do this for several thousand dollars. 

I think the "hand on speaker test" with some thumping bass would provide a substantial clue regarding whether spikes or springs are either one changing the game as far as speaker vibration is concerned.  I suspect that neither will show any difference in that test, though here, as in listening, perception bias will play a part unless you enlist at least one other person in a blind test so that you do not yourself know which is which.  Even there, the speaker on springs will have some perceptible wobble in response to just your touch which you won't be able to ignore/forget.
For tower speakers on thick carpet, spiking through the carpet it to whatever floor is underneath may be a good idea for stability against toppling.


Spiking the speaker to the floor (if it actually works as intended) would restrict the translational fore-aft rigid body mode, but it would do little about the fore-aft rocking mode.


These statements appear to be at odds with each other. 


An accelerometer would quickly put most of these questions to rest concerning cabinet movement at the stimulus frequency.  Using multiple placements would allow removing cabinet flex from results. Edges and corners should have least flex.
@wokeuptobose, I am keen to hear a report from your upcoming experimentation; I do hope you will post back to this thread or at least put a link here.  Thanks!
@mijostyn, I wonder if what you are feeling with hand on speaker is primarily flexible modes being excited, which locking the speaker to the floor will not really attenuate.

Spiking the speaker to the floor (if it actually works as intended) would restrict the translational fore-aft rigid body mode, but it would do little about the fore-aft rocking mode. I suspect both of these modes for most speakers are in the sub-1-Hz range. I am skeptical that any true acoustic benefit of spikes derives from them actually anchoring the speaker to the floor, though their ability to keep the speakers from walking might be valuable.

Have you done the "hand on speaker" test both with and without spikes (same music, same electronics, same everything, except with/without spikes)? I have not, but my intuition tells me that you may feel no difference(?) I would put the same question to the "spring and damper" crowd.

Based on anecdotal evidence from others and the differences in opinion regarding the physics involved from experts (Richard Vandersteen and others), I suspect that:

  1. There may be some real difference (better or worse) in SQ between the manifold options (including doing nothing).
  2. It is difficult to know whose grip on the physics (if any) is correct.
  3. It is difficult for me to entirely reject that perceptions based on bias will unavoidably be mixed with perceptions based on true acoustic reality--and I mean *anyone’s* perceptions. The ability to conduct a true blind A/B/C/etc. comparison between options, realistically for real humans, is limited at best, especially for heavy floorstanding speakers.
  4. The truth regarding the physics is, and likely will remain, both complex (much more than "gotta keep the speaker from moving" or "gotta let the speaker move") and elusive.
  5. Experimentation with one’s own ears (but see Item #3) and equipment would be the most profitable path forward, to the extent one wishes to invest in the experiments. Personally, I have way too many other interests, including a soon-to-be-seven-year-old, to invest much more in this particular enterprise--at least until my new system is set up and I start itching to mess with it all.
  6. For tower speakers on thick carpet, spiking through the carpet it to whatever floor is underneath may be a good idea for stability against toppling.
As Einstein said, “It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.” (often misquoted)

Thanks again for all the input.


linnvolk, That is correct. Spikes lock the speaker to the floor. It is the speaker resonating that you are worried about. Play something with a loud bass line and put your hand on the speaker. That vibration you feel is the speaker resonating. Locking the speaker to a solid floor minimizes some of this but not all. Any vibration you feel is distortion. It is usually low down so it is the woofers causing the problem. Because the forces on the speaker are rarely symmetrical the speaker can slowly walk across the floor. I have seen this happen on both wood and carpeted floors. Spikes prevent this. 

Some people think that isolating the speaker on springs helps to keep the floor from resonating. This is another example of lay intuition run amuck.
The speaker just resonates worse and the floor keeps resonating just the same. If you want to keep the floor from resonating put the speaker outside. Heavy carpet will dampen it to a degree. 
I’ll second Townshend podiums. They are awesome if you have deeper pockets than me. A game changer I hope to own one day (soon preferably).
aschuh

Specifically, I measured a 12" Rhythmik sub, front firing, at minus 3 - 4 dB, when sitting on Nobsound springs (compared to standard hard rubber footers), which obviously allow for horizontal movement.
The loss in bass energy was quite audible.

I do not think this is physically possible. Estimating the speaker weighs 50lbs and the cone and voice coil 8 ounces, the speaker cabinet would move 1/100th as far as the cone, for an equal and opposite reaction, assuming 100% of the energy moves the speaker. The cabinet is larger in surface area, but 3db is a 50% loss in acoustic power. This is not possible.