Hello rixthetrick,
Nice post as it describes spring function, zero stiffness and how they relate to isolation theorems and functionality.
We have experimented with springs and isolation techniques for several years.
Our take on the use of a steel plate foundation is the material and mass has natural damping factors that relate well to the mechanical grounding element of the steel springs taking more energy from the springs to floor-ground and at a faster rate of speed. This establishes a resonance conductive mechanical pathway that allows for a greater level of energy dissipation. In our experiments we used steel, brass and copper alloys at a 5/16” thickness. There was a noticeable improvement in sound going from steel to brass.
When we moved to copper, being the harder material with lesser damping factors we had to use a different spring geometry to improve performance over the steel and brass. I would enjoy hearing your findings should you ever decide to test these materials on your model.
The springs worked but due to springs having weight restraints the company decided to discontinue the research. We also noticed within our models that timing artifacts (shortened decays, depth of field and imaging issues) possibly created by speaker chassis movement limited the sonic in comparison to lesser movement by resting the speaker on a rigid direct coupled structure. Please keep in mind that our products are designed to vibrate so there is an infinitesimal movement within these systems as well.
Our focus is on resonance reduction in components, on electronic parts and loudspeaker surfaces providing resonance and noise a conductive pathway to rapidly exit the chassis per the laws of Coulomb friction and damping. The isolation techniques we are familiar with retain most of the resonance inside the chassis and are more focused on outside disruptions.
The sonic results between the two philosophies are quite different as they should because the theorems, applications of technology and product designs are opposites.
The best example of proof relating to electromechanical noise and signal blockage due to resonance build up is taking any version of active iso-tables regardless of price that are used in supporting electron microscopes and placing any of our platforms beneath them. The sonic results from any audio component residing on the isolation device will audibly improve hence providing some supporting evidence where electricity powering the iso-table becomes the noise generator affecting the signal.
Disclaimer: Our participation here is not to challenge, disprove or say this sounds better than that, as public opinion and Industry reviewers steer those ships. Once we realized that resonance formed by vibrations is the primary culprit involving signal clarity, the choice made was to work on taking the source of the noise (resonance) out and away from the instrument (Resonance Energy Transfer) in comparison to focusing on the worldly inaudible and sometimes audible disruptions getting into the instrument (Isolation). Both technical approaches have merit.
Robert
Star Sound