Mounting your speaker on a rigid support, such as a spike or a cone or a single slab of rigid material, will allow vibration to travel out of the speaker and down through the floor towards the equipment rack. This is a significant problem for rooms that have both concrete floors and suspended wood floors but is a very serious issue for listening rooms that have the latter. Additionally, if the electronic components are also on a rigid mounting vibration will travel up from the floor and into the equipment which will contaminate the signal. Rigid mounts are not "one way" transmitters of energy. Because they are rigid they allow the energy to flow both directions - out of the equipment as well as up into the equipment. Additionally, using materials that have their own sonic problems (such as materials that ring: stone, glass, metal. etc, or materials that are resonant: natural wood, Plexiglas, acrylic, etc) will impart those unwanted characteristics into the components they are supporting.
The optimum method for supporting a speaker is to place it on a high mass, high absorption platform that will decouple the speaker from the floor as well as absorb unwanted stored energy (vibration and resonance) out of the cabinet and change that destructive mechanical energy into a more benign form such as thermal energy (heat).
Disclaimer: I am a manufacturer of vibration control products.