The spikes should go through the carpet to the floor underneath. If it is unsteady, rocking on the floor, you need to adjust the height of the spikes to steady it. If the spikes are not going completely through the carpet to the floor, you need to unscrew them until they extend enough to reach the floor so that the bottom of the rack is above the carpet. The levelling process can take some time, because floors are not uniformly level and each time you raise or lower one spike, you may need an adjustment in another.
Foundation for the equipment rack on carpet
I just bought Atlantis Reference 5 audio rack, which is pretty heavy and stable piece of furniture. I installed spikes to place it on the carpeted floor (berber carpet to be exact). The rack is very wobbly on the carpet, so I'm thinking about either putting some kind of heavy foundation- like ceramic or marble tile on the carpet first and still use spikes, or maybe try the supplied feet instead of spikes. Should I put spikes directly on the foundation, or on the metal (pennies), and should I isolate the foundation from the carpet first? The same question is for the speakers- Paradigm Studio 100. I can forsee the "endless" possibilities here. Appreciate your opinions in advance. Regards!