I've noticed that many recordings from radio announcements and such seemed to have a very distinct vocal style. Is there any political/psychological significance to that?
It's called the Transatlantic Accent or Mid Atlantic English. It's not a true regional accent but was a style of speaking that radio and movie people specifically trained in after movies got sound. It became popular for several possible reasons, it sounded vaguely upper class yet still universal, and was thought to be more aurally distinctive. It fell out of use around the end of world war 2 as more people who didnt use it entered into show business.