@rkonze – I guess the thing to do it browse through the gallery. The user galleries have a lot of useful photos. Yeah, and don’t worry, the bar won’t be going anywhere. I actually would not recommend placing a sheet of plywood under the framing, just place the base framing directly on the carpet.
The plywood might make it too easy to move.
My only concern with carpet is the cleanup of the inevitable spills. I usually cut back the carpet and install either floating hardwood, vinyl or tile flooring…something that can get wet. That or just be careful.
My bar is directly on the concrete, then I tiled around it and then transitioned to carpet.