"Rick" wrote ...
I have recently bought a nice theater system. The problem is I live in
a NYC apartment, and I'm receiving mad complaints from my neighbours
about the powerful bass. I'm sure there are people who have similar
problem. How do you effectively reduce noise/bass in an apartment? Any
success stories? Ideas? Suggestions? Theory? Please help!!! Or else
I'll have to give up my system. Please don't....

Install one of those bass transducers (the kind made for shaking
walls, floors, etc.) on your chair. Or listen with headphones?

Isolating that kind of LF sound is just impractical in your situation.
The Physics of Sound. Its not just a good idea, it's The Law! :-)