Quote Originally Posted by Cilia View Post
It's a matter of collective unconscious. Since souls are recycled through the Lifestream, a lot of people have subconscious memories of the Final Days; however only those who inherited an Ancient's soul that maintained its integrity through the ages and the cycle of souls can actually awaken to the Echo.

So if you've got a mostly intact Ancient's soul you'll awaken to the Echo, if it's been degraded too much you'll just have the feelies, and if you've got a soul born after the Final Days you'll feel and hear nothing at all. (Beyond the starshower itself, which may or may not be illusory.)
I'm pretty sure that's still speculative. A reasonable conclusion, but not confirmed.