Spikes versus Rubber on wood floor?

Nsgarch - Got it, if the speakers do not rock back and forth over a single joist, they will rock better on the music.

Exactly!

If you want the speakers to stand as still as possible while playing, spikes are the least likely item to do the
job! Quite the contrary to many peoples belief, they act as a "tuning fork" and excite floor resonances. These floor resonances will be perceived as delayed sound, that is in no way in harmony with the origional sound.
Decouple the speakers from the floor ,and you are more likely to obtain a good result. Don´t just use rubber feet,instead try some "soft" feet that are made from a material that is in accordance with the weight of your speakers. You have to weigh your speakers at their front and back to order the right stuff.Here in Sweden , there is a brand called "SD-foten" , but there are more brands than this one. The resonance frequency of the decoupled speakers should be in the vicinity of 8 Hz , I think.

An Italian reviewer thought he heard doppler-distortion, when using such devices as SD-foten , (because he was able to rock the speaker back and forth). Talk of expectaitions ! Measurments has shown the opposite to be true.Even a Swedish hi-fi magazine that was sceptical at first , did find it possible to place a coin on its "edge", play loud while the coin was still standing. If plain physics would role , instead of marketing "hype" , good sound would be more common.

Hello Gammajo. There are lots of threads on vibration isolation that you can research on Audiogon. I'll agree with everybody else who have posted comments to the effect that speakers should not move (except for the drivers), so rubbery feet are not too good. I also believe that cones (Tenderfeet for example) are better than spikes. Both sit on a point at the speaker/floor interface. However, a cone places the speaker closer to the floor on a broader base. It isn't as wobbly as a spike. In my view, an excellent product for hardwood floors is the Superspike. It's an integrated spike and pad to protect the floor from the spike tip. The speaker is on a spike but you can move it around without putting little spike holes all over the floor.

MarkPhd Thanks for your input. I have been scanning threads for awhile but found them confusing, particularly when you add in the different needs of different components and types of flooring, so I thought I would post just for my speaker application.
Frankly I still am confused. I guess there is no clear consensus of spikes versus Tenderfeet type cones. It would seem to me that spikes if they are indeed able to draw out vibration from the cabinet would then vibrate the wood beneath and the adjoining spikes would act as a megaphone and transmit it back to the cabinet. Yet any type of soft rubber would allow the cabinet to move (jiggle). It leaves me wondering why something that is more inert and sound insulating yet not metalic such as styofoam would not work better.
WTB do you know who sells superspike?