I broke down (because I'm ridiculous) and put spikes on the bottom of the stands. I had them left over from some subs I sold long ago and forgot all about. If you're like me you have a box of random cables, cords, and speakers spikes in this case.
I can say, without a doubt, spikes exist for a good reason. What I have learned is speakers like bookshelves need all the help they can get for making bass. It seems the less energy imparted from the speaker to its platform the better. I noticed with the spikes far less vibration in the floor.
On the otherhand, if you have a speaker that is bass heavy or muddy sounding, I would definitely give the stick on rubber feet a try. It definitely tightened up the bass but drained it a bit. It even seemed to take some edge out of the treble. From what I have read, they seem ideally suited to M3s.
From all this experimenting with treatments, positioning, isolation devices, measuring room response, etc. I'm starting to find it really is a journey to get a system sounding its best, and yes, Audio is a wierd thing.
