Originally Posted by rynberg
The idea behind spikes is to help "decouple" the cabinet from the floor surface. While the cabinet isn't truly decoupled, the very small surface area of the spike tips does reduce the amount of vibration transmitted to the floor structure, as compared to a no-spike situation.
Quote from my M&K 150THX Subs.
"By mounting these spikes into the threaded inserts mounted in the bottom of the subwoofer, you can elevate the sub, and on carpet, COUPLE it more tightly to the floor"
They didn't say "decouple". They said "couple".
The way I understand it is that the issue is not the amount of vibration transmitted to the floor structure, but the amount of wasted energy that the sub cabinet reproduces when spikes are not employed.
Another quote from a review of Mission Speakers
"Now spikes may not sound like much, but they do two very important things. Firstly they couple (not isolate) the subwoofer's cabinet to the ground. They do this efficiently by being sharp, punching through carpet, rugs, small children's feet and 35 years of under-carpet grime and gunge, to get to grips with Mother Earth (or as near as possible). A good spike will actually sink a very short way into the floor, in this case being quarry tiles, and bed itself firmly to prevent lateral movement of the subwoofer. Once effectively attached to Mother Earth, all cabinet resonance is transmitted down the spike..........
Now maybe, there are some other theories at play here, but it has always been my understanding that spikes "couple" the speaker to the floor to eliminate cabinet resonances, thereby eliminating wasted energy........and if that's the case, than anything between the spike and the floor would contradict what they are used for in the first place.