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
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.
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
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!
@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.
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.