Theaudiotweak...The natural period of swinging object (of any weight) on a chain as short as 40 inches is one second, not an audible frequency. The force exerted due to cone motion (its mass and air resistance) is a few ounces, and won't move a 100 pound speaker system enough to be detected. So the idea that the speakers will be swinging around wildly when they play is only believed by those who have never experimented with this setup.
Spikes, or other means of mechanically coupling the bottom panel of a speaker box to the floor may damp vibration of that bottom panel, but will do nothing for the front, back sides and top. Vibrational energy does not need to be "drained" like a fluid from the box. Damping material in and on the box absorbs the vibration which produces heat. The heat does indeed escape from the box, but you can't hear heat.
Spikes, or other means of mechanically coupling the bottom panel of a speaker box to the floor may damp vibration of that bottom panel, but will do nothing for the front, back sides and top. Vibrational energy does not need to be "drained" like a fluid from the box. Damping material in and on the box absorbs the vibration which produces heat. The heat does indeed escape from the box, but you can't hear heat.