Ways to Reduce Atmospheric Noise

The noise generated by appliances such as a compressor in a refrigerator or the spray nozzle of a dishwasher resides well above the bass regions, and good old absorption and isolation is the key here. The first thing you should do, as suggested above, is mechanically isolate the refrigerator from the floor. Just as you would decouple your TT, you don't want the vibrations of the refrigerator to interact with the floor and walls translating into noise. Many times, this alone is enough to satisfy. If not, I would try free-standing absorption in your listening room with an air gap between the kitchen wall and the absoptive panels.

The creeking floor is the hardest... That would certainly require intervention and a mechanical fix from the landlord!

Yes, that totally explains the best approach to the problem in the kitchen. I'll opt first to place a floor mat of synthetic material under the refrigerator and then go from there. I'm also cogitating about placing free standing panels behind my electrostatic speakers. I like the acoustics in the gallery seating here in Cincinnati's Music Hall and while being in an apartment that's not exactly relevant to my situation , I'm nevertheless curious about what can acoustically be done to a room via artificial means.

Some hardware stores sell tiles about 2 feet on a side....usually in 4 packs.
The tiles link together. I use 'em in front of my workbench and have one for yardwork, as a kneeler. They are about and inch thick, hard foam.

Refrigerators do need some space between surrounding areas to operate effectively.

At first glance I thought this post was about cosmic rays and shielding with foil hats, but to my surprise and immediate realization, I have a noisey frige too! So thank you, and I am gonna get some material as well to isolate the darn thing.