The issue with carpet and padding is the ability of the speaker to move back and forth in response to the force from the woofers. As a result you normally want to have spikes that go through the carpet, and you want them as far out as possible.
With some speakers, which have spike holes directly under the cabinet, it's too narrow a footprint for safety and you will need outriggers.
With some speakers, which have spike holes directly under the cabinet, it's too narrow a footprint for safety and you will need outriggers.