Interesting idea. Please clarify:
Wall Street is home to the New York Stock Exchange. The Federal Reserve is several blocks away on Liberty Street. There is more space near the Stock Exchange, because the street is closed to traffic, but it is swarming with police and guards. I have no idea whether they would allow a small group of people to stand around and play music. There is a little plaza behind the Federal Reserve Bank that would have space for a demonstration. I don't know who owns the plaza and how they would respond to a demonstration.