I placed exotic wood spindles under my 20.7s.
I tried a few different woods, and like Bloodwood spindles best. 1.5 x 1.5:by 18" (2) and 12" (4)placed diagonally like a chevron .. two 12 outside, 18 as a V and two 12 behind the big V lengths. under the stock large oval base.
It tightened up the bass and made it cleaner. tightened up the vocals. made the sound warmer. more lifelike
This exotic wood stuff is the very first thing I ever found to BOTH enhance clarity and enhance warmth.
I tried African Blackwood. which added a lot to the bass, and enhanced the treble, but did zero for the mids. so nope.
I also tried Bolivian Rosewood and Brazilian Ebony.
THe Brazilian Ebony was also good.
One thing I noted was first added the spindles the sound changed. then went back more to the way it was the next day. ... the reason was the wood sank into the carpet. dampening the effect it had. So I used small 1/4" by 1" by 3" blocks of hard maple (all I had) under each spindle end.(the small blocks sank into the carpet almost completely) the original change to the sound came back and stayed.