These kind of things in games bother me but I can't think of any good ideas. But here goes.
FD has said that the sound is important in this and that we're overthinking it. Everyone is trying to decrypt it and using various methods to alter the sound. If it's so simple, maybe the audio is useful as is. It broadcasts its location in a form of morse code. Maybe that is what is important. Perhaps the location they spawn in is important. Has anyone tried mapping common spawn locations? Any common property of all the systems?
It is highly unlikely to be morse. Morse was thought up by humans and is not universal. If there were something, it would be in something like binary or another base system, as those are universal.