Speaker Support - Three Feet or Four

Three is fine if you have no problems with tipping. Generally you would want the feet as far apart as possible.
Only if it introduced some sort of resonance would that not be best.
And two feet front, one back is right.

I have done it both ways with several different speakers but always using Sound Anchor stands, which add significant weight and lower the center of gravity. My current speakers are 110 lbs each (not including the stands) but are moderately tall and somewhat slender. The Sound Anchor cradle bases extend the footprint and I tried using three Eden Sound Bear Paws for a three point support. That simply was not stable enough and I switched to four feet, which I find to be a much better solution for my present situation with the feet piercing carpet and supported by the underlying concrete floor. I previously used Sound Anchor stands on three feet to support Alon 5's on a suspended hardwood floor. In that scenario, the three feet worked fine. However, it is my recommendation that 4 feet is better than 3 feet to support large speakers.

For my KEF 104/2 speakers I use 4 Edensound Bearpaw Sr feet that have the Triceratops option on the top of the footer. This is the Edensound version of Mapleshade's triplepoint feature. Each Edensound Bearpaw Sr was then pre-drilled so that the Bearpaw senior could be attached to the KEFs. I felt this was the most secure option but man oh man did the Bearpaw Seniors as feet really add weight to the KEFs. Moving them around was a real work out. I say stick with the four feet. In my instance I've got a lot of stability and I have kids to worry about.

Alas, for these speakers at least, the three feet option made them quite unstable.

I've now gone back to four feet - very stable

Still considering the outriggers, but with a four feet

That's weird. Nobody mentioned which sounds better, three feet or four feet. Oh, well.

One possible solution to the instability is to have three feet, and added on the two unsupported corners, have supports with are just below the speaker base. So if it starts to be tipped, it cannot. and the center rear point is the only support when steady, the extra two a paper then gap under the speaker base?
Kind of like a bicycle with training wheels?

When I first got these particular speakers I had them on some temporary spike protectors that were not as hard as the brass that I now use.

Switching to the brass made an audible difference - so for these speakers at least, eliminating all movement is best.

When I tried the three point with two point at the front or rear the speaker was very easily rocked. So much so that I did not even try listening to music.

One last config was to try placing the two feet on one side and placing the third foot directly under the CoG line on the opposite side. This was more stable than the other config, but the 4 point solution is still the best.

Other speakers might benefit from three feet if their centre of gravity is more toward the front or back, but these just proved too unstable.

A friend has a pair of Reference 3A Veena's and their CoG is very nearly over the back feet, making their 3 point system very stable.

A good outrigger design will allow for easy adjustment when necessary

Soundocity an Galen Carol look to have some pretty robust products - if anyone knows of any others I'd really appreciate knowing about them.

Thanks

"Nobody mentioned which sounds better, three feet or four feet."

With 40# Sound Anchor Stands and Bearpaws, there is plenty of mass and low COG so that, in my system, either 3 or 4 footers sound the same, as long as the speaker is stable at all listenable volumes. I suspect perceived differences could be greater on a suspended wood floor but other things may be going on in that case, such as a greater potential for resonances than on concrete. It is still my belief that 4 footers is best as long as you can properly adjust the footers for equal contact.