Background vibration and your system.

I never understood hard footers.  The company I retired from does quite a bit with vibrations related to construction activities as well as background readings and we designed suspension/damping systems for machinery and in one case for auditorium balcony seating where resonant oscillation was a concern when the crowd would stamp their feet in unison.  In most cases, the problem was modeled as springs and dash pots so the solution was a form of damped spring, or an elastomer. I suspect the same thing works for audio equipment with one goal being to dissipate resonant energy occurring in the audible frequency range - think Townshend’s platforms with damped springs for support or any of the elastomeric solutions.  Mass loading could help too.  I suspect there may be some papers you could look at related to the seismic effects on sensitive instruments or maybe on audio equipment.

@erik_squires - There has been research resulting in useful products like those from Townshend, SRA, and other companies that many here benefit from. The most prevalent applications have probably been in mitigating vibrations acting on turntables.

On the flip side, IMO there are also products marketed using pseudoscience and/or exaggerated claims, which muddy the water.  As you indicate, the absence of documented research has left the audio equipment industry without consistent/uniform vibration measuring processes and baselines.

Regardless of the application, the principles are consistent and solutions involve various implementations of mass, springs, and damping as presented in this link and this link.  However each application is unique depending on what is being isolated, and from what vibratory source.

In our audio world, springs are successfully used like Townshend platforms or the inner tube discussed earlier, which is an air spring.  Commonly used elastomeric footers are also a form of damped spring. Many audiophiles mass load with brass or other materials, and many types of turntable stands and platforms seem to be successful at mitigating the effects of vibrations. However, without clearer documented research and guidance it is mostly a trial and error endeavor in the audio world.

@deep_333 - I switched from spikes to Herbie’s products, to damped springs and then to these platinum silicone elastomers, which can be easily sized for the equipment or speakers being supported. The springs worked great but the silicone elastomers (I believe at duro 20) provide most of the benefit with improved user convenience, IMO. YMMV

Many manufacturers take their own stab at resolving possible issues for their own gear. I say possible issues since every system location is different with different external influences, like flooring type, size and support of nearby speakers, rack and support conditions, nearby traffic, and more. The manufacturer can only do so much but some do try like SMc Audio and their gravity base (large brass plate with components anchored directly), and the many that use elastomeric stand-offs, applied damping materials, constrained layer damping, special coatings, and the wide variety of compliant footers.

For a time, I used spring supports under all my components and speakers.  I have found that paying attention to solid rack support, platforms like Z-slab constrained layer shelves and the black diamond shelf, and compliant footers has worked well in my system.