Make some pads.. Screw four 2x4's together and make a box the size you want. Coat the insides with Crisco. Mix some self leveling concrete Fill to the thickness you prefer. Easy
Level the floor
We've just moved. The audio playpen is the basement, which has an issue I haven't dealt with before: uneven floor. Left-right is level, but front to back there's a steep slope. At a distance of 18 inches, the slope is about one inch.
I figure others have dealt with this enough that there's "a way" (or an eternal argument...). Educate me?
Available equipment would be fine; surprise uses of stuff would be terrific.
Thanks.