Flooring advice on basement listening room.

I had a portion of the basement converted into a dedicated audio room. 2 3/4 sides have concrete walls, but the remaining 1 1/4 side, I installed double dry wall on both sides with Green Glue between them. I have carpet over concrete and it has worked great for me. Your wife will also love it.
@ghosthouse has mentioned about GIK panels - these will work great when placed properly.

Whilst it’s true that cement slabs are better than wood floors since they’re much stiffer, you’re not out of the woods yet because seismic forces, including Earth crust motion, cause the entire building, including the cement slab, to move in all directions. Like a boat 🛥 is moved up and down and all around by waves passing under it. That’s why seismic isolation is beneficial even for rooms on cement slabs. When you isolate something you’re isolating it from the entire building and the motion of the Earth. 🌎

geoffkait. You're talking about extremely minute movement and at very infrequent times here. How does this affect one's system???

No. That’s what you say I’m talking about. 

Well, I guess if you ask a stupid question, you get an idiotic answer.....