I bought two of these cutting boards, marked and drilled 5/16 holes at the four corners inside of the drip rail. Screw in threaded inserts and then the cone points. Flip over and the bottom surface is now the top and is completely smooth edge to edge. Set them in living room with a level on top of them, adjusted until dead level and tightened the locking jam collars. No matter what speakers I put on top, floorstander or stand mount, spiked or decoupled, they have a plenty large enough base to work from and always level. I needed to compensate for an un-level subfloor as well as gain a few inches in height because of my listening chair. Roughly $100 all in, look pretty decent and perform well for the investment.
https://www.ikea.com/us/en/p/aptitlig-butcher-block-bamboo-00233429/
https://www.parts-express.com/Dayton-Audio-DSS5-BK-Black-Spike-Set-4-Pcs.-240-684
https://www.ikea.com/us/en/p/aptitlig-butcher-block-bamboo-00233429/
https://www.parts-express.com/Dayton-Audio-DSS5-BK-Black-Spike-Set-4-Pcs.-240-684