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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
ausaudio
90 posts
 
The statement you are referring to is backed by technology, physic.


I am all ears. What technology and physics?

By changing the effectiveness of the grounding plane (platform or spikes), the transfer of resonance becomes reality where your book-mentored approach might change as well.

Resonance cannot transfer. Mechanical motion can transfer. Sound can transfer. Changing how you couple something to a ground plane can impact the resonance point or size of the resonance by changing effective mass, damping, or spring ratio. There is no transfer of resonance.

Vibrations (mechanical, electromechanical or airborne) establish resonance and clogging of the signal pathways establishing component operational inefficiency.


Resonances do not clog anything in a signal pathway. They may add to the signal as a non-harmonic component, or they may modulate the signal creating harmonic and IM components. They do not clog anything.
ausaudio
90 posts
 
This stuff wears me out. How many illogical analogies can be made in one paper....how many times can you say "Coulomb Friction"....why not just say, "only our product will fix the problem you didn't realize you had....." Props for persistence though...


Agreed, but I stand corrected, your quote I believe referenced tater salad with mayonnaise dressing left on the counter far too long and long since rancid.

Personally I would have just used the more common name for Coulomb Friction ---- friction.  I assume this is to confuse people to think it has something to do with electricity, but in this case Coulomb is a person's name, not an electrical constant. 

Of course, that tater salad makes the assumption of the sources of energy, and where they are going, relative amplitude, etc. and hence makes a blanket conclusion for mechanical grounding.
mitch2
4,334 posts
 
@ausaudio - I may have misunderstood your response but I am not the salad guy, just the guy tapping out after seeing enough pseudo-scientific rhetoric used to try and sell audio stuff. 

BTW, Coulomb was an 18th century engineer who is best known for Coulomb's law, which addresses the proportionality of electrostatic forces of attraction and repulsion.  The scrapyard guys who lift old cars using an electromagnet are probably thankful for Coulomb.  His name also defines the SI unit of electric charge.  He did do work in friction, and Coulomb friction is a model used to predict the direction and magnitude of the friction force, and acceleration, between two bodies with dry surfaces in contact, taking into account the relationship between static and kinetic friction, and how those may act with respect to a system where there could be a variety of contact surfaces and loading situations.   I am skeptical as to the applicability of the model to spiked audio equipment platforms, at least in the manner portrayed.  Of course, my impressions of their marketing scheme has nothing to do with the success and value of the products they produce with respect to spikes, platforms, and more.
ausaudio
90 posts
 
@mitch2 , I know you are not the salad guy.

Whether the model applies or not, using Coulomb friction in any literature directed at audiophiles, to me, is not above board, as most would have no idea that means nothing to do with electricity (in general).  I think we are in sync on our impressions of marketing. Whether it applies to the matter at hand, it is just one of many forces that would be in play.
linnvolk OP
91 posts
 
Anyone who has taken physics (which includes anyone with an engineering degree) should know what Coulomb friction is.  It may be more widely understood than not.  But we digress...
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