Sub setup in acoustically dead room

Hi. I have a REL Strata III that used to sound terrific in a different house. In my new house it sounds rather lifeless and needs a lot of volume to generate acceptable bass levels. The new room is smaller than the old room but is much more acoustically dead. I now have the time and room to fix this problem. I'm gonna try moving it around tonight but something I was considering was putting a 2' x 2' sheet of MDF under the sub instead of placing it directly on the plush carpet. Anyone ever try this? What are the pros and cons? Thanks! leo.
If you're in a new room with new speaker/sub placement, have you tried adjusting the "phase" control (or other controls) on the sub? Perhaps you need a different crossover point?

It may be the size. It's possible that the larger room supported modes at lower frequencies to your taste/needs. The smaller room will have higher modes regardless of damping.