i don't see cement board killing much of the foot traffic noise, nor subwoofer noise. but other noises, yeah, probably somewhat.
what you need it dampening = carpet.
i used to live in a cement condo. it had flexicore with cement over it. hard shoe traffic could be heard in the hard flooring areas. in the carpeted areas, not so much.
what you need it dampening = carpet.
i used to live in a cement condo. it had flexicore with cement over it. hard shoe traffic could be heard in the hard flooring areas. in the carpeted areas, not so much.