Speaker Spikes - Working Principle

I suspect that the less the structure housing a transducer moves/resonates during use.. the better it can sound.. or at least the less it would influence the sound (although this wouldn’t seem to be a linearly proportional relationship). It might have a negative effect if it’s within the operating range of a particular transducer. If the structure is perfectly motionless at any frequency or amplitude (regardless of what the transducers are up to), that would seem to be a perfect enclosure as a foundation for audio reproduction. No energy loss. Exhibit A.. Acora speakers. I think I remember one of the Acora’s (or a presenter?) saying the reason for the granite enclosures was so the kids or dog couldn’t knock the speaker over, but they were probably half joking.

If the footer technique merely transfers the resonance of the entire structure above or below the operating range of the tweeter/midrange, then that may be acceptable (much like we find second-order distortion acceptable with amplification in our electronics). Of course that assumes the entire structure is rigid.. if the panels or sub-components independently move to their own resonance frequencies.. then that is another problem and it’s unlikely what you place underneath will help as much as you hope.

I’d also suspect that a speaker with a large monopole woofer being driven by a high current amplifier (at high levels) and it’s cabinet is resting on ceramic balls or springs or any soft material with a range of motion.. that can’t be good for the impulse response or phase continuity of the other drivers. Coupling with a large mass might be a better solution (vs decoupling), if done well.

(Disclaimer: I’m not a materials specialist or a physicist.. just an audiophile who used to like physics once).

Has anyone invented vibration control wheels/castors?!  My wife always like to tidy up and move my speakers to the back wall!

@kraftwerkturbo Really?  You thought I meant that a tweeters motion is moving the cabinet.  I reread your question and my response and I suppose that I should have said that the bass drivers in the speaker cabinet would cause a slight motion, enough to blur the image coming from the tweeter, and possibly midrange because of the pistonic motion of these drivers are so short.  So the spikes are there to keep the speaker from moving, hopefully, not at all.  Not a millimeter if possible.  I thought that this was obvious.  And the Linn demonstration of loosening a single spike on each speaker stand was to introduce this rocking motion, and then pressing down on top of the speakers was to stop that rocking motion.  That's it!  Nothing else.  All that blather about vibration control and dampening is something else for another topic.  The stuff I discussed were simple explanations, examples that anyone in the room could hear.  Not poor or wrong science applied or applications of physics.   

Just re-read this one: "Rubber has a lower internal impedance than say wood which is lower than concrete. The highest internal impedance I think is Diamond.". That is the reason why they are now building all Stradivaris from receycled tires :-)

FWIW, in one if Paul McGowen’s YouTube videos there was a question related to this and he said, spikes (in whatever speaker) produce a more audiophile type bass that many people like, but he likes the more natural bass from eg isoacoustics (or some cheaper similar product).