Can you hear your upstairs neighbor fart? I am not kidding. Walls and ceilings in this city can be so THIN that they barely offer any sound protection at all. I have a friend who just bought a very fancy loft in SoHo, who hears every step his upstairs neighbors (and their children) take. On West 22nd Street sound will not be a problem.
While this apartment still doesn't look like much, most of the demolition is done, and they are working on sound insulation attached to the old wooden floors overhead. Keeping the beautiful, old cross beams, a combination of insullation, sound board, air pockets and sheetrock is about to be slipped between the beams and attached to the floor overhead. Testing for sound is being done by asking the upstairs neighbor to jump up and down while turning his television up high (they are friends).
If you want to have a quiet apartment, getting a grip on sound insulation is essential and understanding how sound is measured is the first step. STC stands for Sound Transfer Class and its numbers measure soundproofing in this way:
56 and up=Excellent
As a reference, you can hear normal speech through a wall with an STC of 25.
Each piece of material you add to the 'sound sandwich' on your wall or ceiling will increase the STC number. Most material will tell you how much it will add. At West 22nd Street they are going for a 55 STC with insulation/air pocket/soundboard/air pocket/sheetrock.
Insulating can be cumbersome, take time, and add expense, but it's worth it in the long run. Besides cutting down on sound, it will insulate for heat as well and make sure you get a good night's sleep. MGR