How important are spikes?

For my speakers i used damping with concrete plates ... 😁

Then i used for each box speakers two tunable set of springs ( by varying the damping load over them all ) one under the speakers and one set under the tunable load of concrete +varying load in grams for fine tuning by ears the timbre perception ... It is not practical to do this in a living room ...But as i already said the most important component is a dedicated room not a costly amplifier...😊

But the results were stunning ...Not only vibrations decrease but resonance change for the best ...

To this add a sandwich set of various platforms under the set of speakers of mixed materials including sorbothane between granite plates , bamboo plate and cork plate and quartz feet in the bottom ( quartz sand in a box will be better but more costly ) ...This was very efficient as it was anyway ... All components being on my very large desk ...No comparison in clarity and timbre between before and after .... Costs : 16 chineese small cylinders set of 7 springs in each.... low cost +peanuts for the various plates and sorb ... Way less than most well known isolation product sold and better results than most especially with the tuning damping load of the speakers and springs asymmetrical in relation to the load  ...

i dont think any spikes at any cost could do the job i did for less money than some...As demonstrated in the very good article above... I never used spikes ...

For my actual very smaller speakers, i used damping too and concrete plate with bamboo plate, shungite plate with sorbothane ... Vibrations is less destructive with them...😊

All my devices are experimented homemade...

for me audio is about the ratio S.Q. versus price then audio is about learning and experiments not about price tag ...

Creating our own solutions cost less , is more gratifying, it is more fun to think and experiment and at the end we learn how to confide in ourself more than in marketing for many things related to mechanical, electrical and acoustical embeddings control... I cannot design a dac or speakers or amplifiers but i can embed them optimally and even modifying them and i did with my headphones and speakers...

Those who said that you cannot trust your ears said in fact that it is useless to train them by experiments and that the only way is "plug and play" always costlier components by upgrades... I will qualify these peoples by a name i will let you imagine... 😉😊

I say that to motivate beginners in fun experiments and learnings... No necessary upgrades BEFORE understanding why and how...

Any type of footers will change the sound due to how they impact different resonating frequencies. There is no right one except the one you feel sounds good to you. Put 4 hard apples under a preamp, and the sound will change. Marketing influences us to buy, and in 45 years in this hobby, there will always be the newest and the greatest.

I think back to the late 70's and early 80's when I heard systems sound so much like real music than todays gear, and what I can tell you, no fancy racks that cost thousand, nor power cords that cost thousands, or any form of power conditioners, or fuses that can cost hundreds if not thousands, or AC outlets that cost hundreds and same for cables of any sort that cost thousands and now even grounding boxes. These became their own market for new sales in the late 80s and really took off in the 90s onward. Any of the above is a crap shoot if you're not like their impact on your system. I am not against the above at all. I used many and sold many due to how they impacted my systems.  Stick with the basics and the best money you can spend on fixing the acoustics of your room, and speaker placement. 

"....Stick with the basics and the best money you can spend on fixing the acoustics of your room, and speaker placement."

@phillyb - Good advice.