WWII ambient sounds to go along with your game

[BunnyPoopCereal]

http://warfare.ambient-mixer.com/hearts-of-iron

[johan_d]

If playing GER or UK, you can use the many hours of recordings from MODS for SH5.
Gross Deutsche RUndfunk and BBC.
Note its from 1939 onward, so the first few years you have to stick to something else.