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.
The Credo video is indeed a bit cheeky, a former distributor claiming to have taken Max‘s work to another level.......Interesting guy (Ozzie) with a background in microwave engineering. I had an enlightening conversation with him decades ago about vibration and damping (in connection with turntables) and he seemed to have all the fundamental principles pretty well nailed down even then. I ended up buying one of his turntables, which I still own today.
@sokogear - If you want a taste of the Townshend isolation products without the cost, take a look at my system page, which shows pictures of individual springs that are damped using very thin-wall heat shrink (somewhat loosely applied) with one or two small holes to allow air to escape.  Other benefits of the heat shrink damping is that it creates a better bond with the bottom of your speakers or speaker stands and it protects the bottoms from being scratched by the bare springs. 
One source I liked using is Century Springs, which have an easy to use spring finder feature where you input the spring parameters you are looking for and are provided with a list of springs meeting your parameters.  I have teed up the search feature for you in the provided link.  Expect to pay about $6-$20 per spring.
Otherwise, try Nobsound.
that are damped using very thin-wall heat shrink (somewhat loosely applied) with one or two small holes to allow air to escape.
Rather elegant minimalist approach, I assume only shrunk at the extremes to preserve its more ’squishy‘ state and prevent friction. I guess another option would be to use an even more flexible (possibly corrugated) hose material and hose clamps..
@mitch2 - as I previously mentioned, I use the Townshend seismic platform (with 4 podiums underneath) for my turntable. It was like listening to a new turntable when I put them in, after I got the correct podiums for the small weight of my table. Every adjustment was noticeable along the way when I was trying a little more weight under my turntable, etc.

I am also going to check back with Symposium Acoustics. They have a great solution also, but couldn't accommodate the small weight of my turntable without having to mess with counterweights that would have had to go on my plinth, which for my table (Rega P8) wouldn't have worked. I'm thinking of putting their version of a podium under each one of my discs to get even more isolation. I'll let you know if I do anything with him or Townshend. I think I can get the Townshend platforms for less than $2500 based on my speakers' weight.
@sokogear - I forgot reading about how much you like the Townshend platform under your turntable, so you are indeed familiar with the benefits of their products and the principle.  Since it seemed from your posts that cost may be an issue (relative to the price of your speakers/system) I shared what works for me at a fraction of the cost. 

Some of this audio stuff seems like a Zeno's paradox where each step is half the distance to the wall.  At what point are you at the wall, even though you never will be, and what is each subsequent half step worth?