Sound insulation and sound absorbtion are two very different things.
Egg cartons are a myth. They do nothing for sound and only create a fire hazard.
Professionel recording rooms might have egg carton shaped foam to absorb sound instead of reflecting it. It has nothing to do with sound insulation. It does not stop the sound. It only stops the sound from reflecting, so that he microphone gets a clear signal without reverb. You can still hear the sound everywhere inside and outside the recording room.
To insulate your ears from sound, you use ear plugs.
Similarly, to insulate your apartment from sound, you basically need earplugs for your windows.