Hello,
The original theory behind "spiking" a speaker, which I believe first came to prominence a decade or so ago in some high-end British magazines, was quite wonky and seemed to contradict basic laws of physics. I won't elaborate because those theories were not credible or supported by any scientific evidence.
Just looking at the laws of physics, if there's less contact area between the subwoofer and the floor--the natural result of supporting a subwoofer or speaker on the pointed tips of spikes--then there will be less transmission of mechanical vibration from the speaker enclosure to the floor. Now, if you're in an apartment and want to prevent floor-conducted vibration from annoying the tenants who live beneath, this is entirely sensible.
On the other hand, if you live in an older house or apartment with wooden floors with no-one living below you, you may enjoy the floor-conducted vibrations that deep bass generates and transmits to the floor in a speaker without spikes. Certainly these floor-conducted vibrations are a natural part of many acoustic experiences, whether in concert halls with wooden floors, in churches, or in dance and music clubs.
Assuming the goal of high fidelity--with emphasis on the "fidelity"--is reproduction of the original experience or a believable semblance of it, then there's a powerful case to be made for using speakers that connect to the floor without spikes. For that reason, I don't use them. Then again, the only thing to annoy one story down from my apartment is the building's boiler!
Practically speaking, spikes are useful on carpeted floors to firmly anchor tall, tippy speakers to the solid floor beneath the carpet.
Regards,
