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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
jchiappinelli's avatar
jchiappinelli
117 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
wokeuptobose's avatar
wokeuptobose
130 posts
 
I have a spring trial in process right now if others are interested. I have Townsend Podiums, and three Platforms ordered. I come from a history of B&W 801 Matrix Anniversary speakers mounted on spiked bases filled with 50 pounds of sand each, speakers on their spikes on that base, and 50 pounds of lead shot in baggies on the top valley of each speaker. Midrange/tweeter module bolted down per design but floated on bags of lead to decouple from the woofer cabinet. Today I have Wilson Sasha 2s on ISO ACOUSITCS GAIAs which I like, but I have allowed these "crazy" spring suspension concepts to get a hold of my thoughts. I only share my history to give evidence that I've been following speaker resonance and vibration for a long time and have tried a few things.  I plan on starting with the speakers and moving onto the preamp and streamer/DAC with the three platforms. I will post what I hear, take credit for my brilliance if its good, and blame millercarbon if it sucks. (he's OK with the blame, I checked) All that said, I will share what I hear. Should be a couple of weeks.
chris_w_uk
52 posts
 
I have a new marketing ploy. Sell everyone 16 screw in eye bolts and 8 bungee cords and suspend your speakers from the ceiling. It's so far out, it's bound to catch on. :^)
arcticdeth's avatar
arcticdeth
1,572 posts
 
Wow, way too much book info on this. 
  I use spokes on the carpet on my speakers. 
 Do they add or take away?  Dont know. Do my speakers sound great,...? YES!!

 Better than just sitting on carpet!

 They do work, they sit off the floor a little bit, allowing a good tone, sound.    I will continue to use the spikes, as sitting on carpet, is just boring.
richtruss
163 posts
 
Thanks Mr Carbon, I had some spare Nobspring isolators in the drawer, very under utilised! I’ve just put them under the corners of my Shahinian Obelisk2 speakers, which until now have been coupled to the floor via their inbuilt casters. An improvement in tonal ‘rightness’ and soundstage positioning of performers. And that’s with one ear a bit congested right now.

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