A few things to consider while trying to acoustically isolate your speakers. Since this is an old warehouse conversion into lofts, certain requirements come into play to comply with the building code. There is most likely, sound batt insulation within the floor cavity and the gypsum ceiling is probably on 7/8" furring channels vs. being directly attached to the floor joists. So you may have some inherent isolation built in. You could probably find out when the last renovations were done. City Hall / Building Permit Dept may have records of the building plans you could look at to see what you're dealing with and adjust accordingly.
But, considering the language about loud music implies the developer/building owner may have cheaped out on sound attenuation between units or you have neighbors that don't like to hear anyone else and complain a lot.
The only real way to know is set up your speakers, get the room tuned in and play some music at your normal listening levels you like, and see if you get any complaints.