Input Needed - Renovating Basement for A/V System

Circumstances have forced us to renovate the finished room in our basement where we have two systems - one is a hybrid stereo/home theatre system & the other is purely for stereo. As part of the renovation, since carpeting is no longer an option, the carpeted floor is being replaced with a high quality sheet vinyl flooring. The sheet vinyl flooring will be installed on top of the basement concrete floor. When the carpeting was in place, the speakers on their spikes were placed directly on the carpeting and the sonic results were excellent. Using the spikes in that manner will no longer be an option. I would appreciate suggestions on what to place under the speakers, with or without spikes, to still get good sonic results. The front speakers for the stereo/home theater system are Verity Fidelio Encores; the speakers for the stereo only system are Omega Alnico Super 8 XRS. Thanks in advance for any suggestions. Best Regards, Steven