I take it you are referring to noise transfer (upstairs noise going into downstairs areas)? I'm going to guess you removed carpet, am I correct?

At this point, you can do one of 3 things:

1. Remove the floor and lay 6mm cork underlay. This is probably going to give you problems with the stairs...but it is the fastest, easiest fix other than 'do nothing'.

2. Add acoustic insulation to the downstairs ceilings. This is costly...but effective. I've seen this done 'PROPERLY' for roughly $7/sf. Yep. $7/sf. AND it's very messy and takes ++time and plenty of materials AND you *might lose 10" of ceiling height....not many lower levels can handle that type of ceiling drop.

3. Leave it alone and learn to live with it...what's done is done. Cheapest option.

I'm sorry to say but you have just discovered the unpleasantness associated with removing carpet and turning to hard surfaces.

Thank you for taking time to craft your great response that clearly laid out the options. At this point it looks like I will lean on the “do nothing”
option for now. It is not bothering us while barefoot walking, only when someone rolls a chair or vaccum or walks with flip flops we notice. Maybe later we may remove the floor and add the underlayment. I believe we need to do it safely to avoid damaging the floor.