Playing around on ascension, and had my headphone volume extremely high. We had finished majority of the easter egg, except past collecting letters.
I was chilling out by the stamin up, and heard a whistle similar to that of the rest of the puzzle.
I looked up and to the left, on top of the building where you open the next door, and I believe I have found a generator similar to that of the one that is sucked into the gersch device for the first step. The whistle was quite evident, but I would like someone else to help confirm this.
Crappy cell phone picture to come soon.