This sound is from Hitler Movie Sounds: Downfall

Downfall (German Der Untergang, Italian La caduta – Gli ultimi giorni di Hitler) is a German-language historical war drama film directed by Oliver Hirschbiegel. It is set during the Battle of Berlin in World War II, when Nazi Germany is on the verge of defeat.
See also: Bruno Ganz, Adolf Hitler in popular culture, Adolf Hitler: My Part in His Downfall (film), Until the Final Hour, Look Who's Back (film), Hitler: A Film from Germany.