i imagine them listening to 1940's music hall which has been put through a techno-machine. techno greta garbo.
If that's a style of music you'd like to hear in reality, there's a great group called Caravan Palace…
and a broader genre known as "Electro Swing"
I recently found this just change country for Emperor and soldier for guardsman and you have a nice IG marching song www.youtube.com/watch
Do youuu hear the voices tooo?