Sound proofing floor

Mass loaded vinyl is the shiznit. I have used it to soundproof a ceiling from the living room above and I have used it to soundproof the family room below my room. Just lay it down and put your vinyl flooring right over it. Not cheap, but very effective. Now, in my rooms I was also able to fully insulate as well. 

I have considered it on the wall between my bedroom and the living room in present house. Works well.

ceiling in this situation:

https://www.audiogon.com/systems/6230#&gid=1&pid=17

floor in this situation:

https://www.audiogon.com/systems/8615#&gid=1&pid=11

Are they "hearing" the bass or midrange/treble as well? It doesn't make sense that all frequencies are passing through unless the whole floor is hitting a resonance with your music. It's pretty hard to stop the long bass wavelengths. Isolating your floor from the concrete is not practical, but would help immensely. Have you set the volume to where you like it and gone downstairs to hear it for yourself? That might help develop a solution.