Can I ask a stupid question?
Has anyone tried just listening for a matching sound on the Galaxy Map? We know that on the system map, different planet types make a different radio noise. Out on the Galaxy map, it seems stars do the same, but I haven't found a catalog like there is for the planet types, so don't know if they are random.
Think about it: Frontier has said that we are thinking about this way too hard, they've also told us to listen to the Artifacts. We keep transfixing on the Morse code, but all that does is tell us where we are already at. Maybe the rest of the sound is what we need to be listening for on the map. The 2 sounds combined is what would allow the devices to act as a navigational aid: Current location + destination.
Granted, hovering the cursor over 400 billion stars would be a bit... monotonous, but it seems like a pretty obvious solution to me. All the clues about the Rift, etc. might help narrow down where to start listening.