A story. Years ago Lyric Hi Fi, the ultra hi end salon in Manhattan, Lexington Avenue to be exact, wanted to isolate its listening rooms from the Lexington Avenue subway which was at its door step. I had visited the place before they did a complete isolation project, and yes you could hear and feel the train, both in the basement and in the ground floor space. They did a major isolation project to get rid of the sound. I think they spent almost $1 million, in the early eighties, in doing the project. I visited after the project was completed. Most of the train noise was gone but you could still feel the vibrations. The moral of the story: move, unless you have $2 million plus.
Also, the Weiel concert space in Carnegie Hall had and still has the problem with train noise from the Seventh Avenue Subway, according to critics that go there often. This was after then spent multi millions in design of the space to isolate noise of the train. If the best engineers in the world can't make it happen, I think there is a lesson there.
