Spikes versus Rubber on wood floor?

I used rubber under my home theatre speakers (Athena s3/p3) and the sound was awful, affecting the bass the most.(bloaty, slow, and absolutely no punch, kinda like: bbllaaahhhhh) I used big heavy cones, and the improvement was immediate. Sorry, I do not recall the brand.

Speakers to perform their best MUST NOT MOVE AT ALL (meaning the tops should not wave around, even a silly millimeter!). So rubber is OUT! Spikes are best, but if you are on a wood floor, you have to be cunning about where you place the speakers relative to the supporting structure, in order to minimize the rocking motion that can result from the floor flexing (spikes won't help with that problem.)

So, how far apart are the trusses?

I highly recommend Herbie's Audio Lab Big Fat Black Dots. These were an improvement over the Audio Points brass cones previously used in my system. I have a fairly rigid engineered truss floor covered with plywood and oak flooring.

Herbie's Audio Lab

Chadnliz -Thanks for the encouragement- its an expensive experiment for me but finally getting to listen to great speakers with great equipment ignited a lust for improvement and you have to start somewhere.
Thanks everyone for the suggestions which fairly clearly eliminate rubber products. The joist supports on 12 inch centers were designed to have a large grand piano placed anywhere with no support underneath for a 30 foot span, so the floor feels completely rigid to the jumping test. I had not heard of the black dots - looks to be an intriguing material.
I have some cermaic tile pieces about the size of the speaker bottom, may compare the stock spikes on these to the balck dots.

Gammajo, here's the deal on speaker placement over joists:

Assuming the joists are running the short way across the room (and that you have your speakers facing the long way) take care to place the front and rear spikes of the speaker(s) as close to adjoining joists as possible. In other words, if the front and rear spikes were actually 12" apart, then the front spikes should be right on top of one joist and the rear spike on top of the next joist to the rear.

Or another example, if the F and R spikes are 16" apart, then the fronts should be 2" in front of one joist and the rear 2" behind the next joist to the rear.

You can locate the joists pretty easily with an electronic stud finder if you can't actually get under the floor and see them.

That is what I meant by "cunning" speaker placement relative to the joists.