Interesting thread.
I have covered 100Kly listening to the 'star song' on the galaxy map. Its how I made my way through the black. A star system has sounds when selected in the galaxy map. After a while you learn what you are hearing. Each planet type has a unique sound and when I listen I can get an idea of what is in the system. Its not a perfect system and doesn't always work. The sounds of birds in the distance can indicate a planet with life. It could be a Gas Giant with life, or a teraformable world, or an ELW. Star song is cool.