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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
mitch2
3,684 posts
 
Assuming you bolt your speakers to your new maple bases, you can then have some fun trying several different supporting footers and listening for changes and preferences. Choices could include spikes, and also decoupling products such as one of the Herbie’s products like threaded stud gliders, giant fat dots, puckies, or giant fat grounding bases; or springs as MC suggested. A good source for springs, that has a multi-input search tool is Century Spring.
ncdogdoc
33 posts
 
I have always mass loaded, and/or spiked. With my current Acoustat Model 3's on a carpeted concrete basement floor, I was quite pleased with the "isolation" provided by IsoAcoustics Gaia III feet. Imaging especially tightened up. Just my 2 cents
golden210
32 posts
 
WOW, this is very interesting. I assume all this is for very expensive systems. I've had many set ups for over 40 years. All in the under $10,000 range. I have just moved and my room is in the basement. Primary gear consists of a Hegel H390, Bryston A2 speakers, moderately priced cables, power conditioner, dedicated power line, and room treatments,. 
I'm very happy with my sound. I'm using the Bryston spikes on a concrete floor with a very thick carpet and pad. If I would try to experiment changing the spikes to something else the time it would take would make it hard to notice any difference. It's not like just hitting a switch.
Maybe with what I have would not make much of a difference no matter what I use.
Like alot of people say, if you are happy that's all that matters.


fdranger610
5 posts
 
Everything vibrates to some extent. We are talking about energy transfer.  Star Sound Technologies website is a good place to learn about energy control devices that truly make a difference in the quality of sound.   They mostly use brass and iron in their designs.  I hope this maintenance tip will help.  The drivers placed onto a speaker cabinet must first have equal pressure on all its fasteners to run true and image well.  A car wheel will vibrate if the lug nuts are loose.... performance suffers.  I bought the Wheeler Digital Firearms Torque Wrench/Screwdriver and torqued each driver fastener to 10 inch pounds. I was surprised how loose some of my driver fasteners were. All of my driver frames now have equal stable pressure within. My speakers image better and bass is more accurate.   Best Wishes to you!
jchiappinelli's avatar
jchiappinelli
116 posts
 
To make sound, a speaker diaphragm must move. It's the movement that pulses the air creating sound. For every movement of the diaphragm in out out, there is a corresponding force that must be dealt with. In the case of low frequency drivers, most of this force is minimized by the flexible surround where the diaphragm is attached to the speaker frame. However, some force still transfers to the speaker cabinet. With high frequency drivers, the majority of the reactionary force transfers to the cabinet. In both cases, vibration (however minute) is transferred to the cabinet. Unless these vibrations are minimized, the result is actual small movements of the cabinet taking the speakers along for the ride. This results in SQ smear and loss of detail.

The purpose of spikes is to couple the mass of the speaker cabinet to a larger mass (the floor) in an attempt to create a monolithic mass that will diminish (not eliminate) the effects of the minuscule cabinet vibrations referred to above. The larger the mass, the less effect the vibrations being transferred to the cabinet will have. BTW, putting discs under the points of the spikes defeats the entire purpose of a spike which is to concentrate a mass.

I am skeptical of springs. By their nature, a spring allows the cabinet to move in response to the forces being applied by the pulsating diaphragms. Any movement of the cabinet would seem to interfere with the stable platform a driver needs to avoid signal smearing.

J.Chip
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