Tenants leaving due to neighbors below them complaining

[Jeff Borrelli]

I have a rental in Chicago. It is a 3 flat condo building and I own and rent out the second floor. I lived there for 3 years before I rented it out. Our floors are not well noise insulated but I really do not want to put in carpets. The 1st floor neighbors are complaining constantly to my tenants for normal stuff including their 1.5 year old walking around. My tenants are moving out, they will live out their lease if they need to but cannot handle the neighbors.  These same neighbors used to complain about my wife and I in the same fashion constantly. My tenants want to move because of how passive aggressive and mean the downstairs neighbors have been, (the downstairs neighbors own their unit). Is there anything I can do since this will be an ongoing problem due to ****** downstairs neighbors?  I now own a couple rentals but I am still in my first year on all of them and self managing so far. Thanks!