For another thought experiment: if you cannot hear that original first sound on take-off, which one can you hear? 10 miles from you? 1 mile from you? That will

For another thought experiment: if you cannot hear that original first sound on take-off, which one can you hear? 10 miles from you? 1 mile from you? That will be the virtual first sound to you, determined by how much weaker the sound has become on its trip through the atmosphere, and how that relates to your hearing threshold. But it will not always and exactly be at the point where the plane has reached its closest point to you (as in the article).