BDR Shelf under speaker

I was thinking of putting a shelf under each of my speaker. Has anyone tried it and is it cost effective? Thanks.
I would rather fit the speakers with the BDR cones, then use the BDR Pucks or the Thick Pucks under the cones. Hugh improvement.

BDR carries stud adaptor of a few popular sizes, so you should have no problem to fit the cones under your speakers.

The cones/pucks combination should be cheaper and more effective than using the DBR shelf alone.

Have fun.