@gotvinyl, thanks for the compliment. Yes Duke's Swarm or Debra are great and great value. However although the multi-sub approach is amazing I find that the lower frequencies in some rooms take too long to decay and some help from bass traps help reduce the decay time and provide even greater improvement.
Measurement using REW or similar is the icing on the cake to really dial things in. The CSD or waterfall plot clearly indicates where any problems or resonances lie.