The only time I have heard what I'd call angelic voices, were not technically voices or talking, but rather what sounded like a multitude of angels singing, while I was in the grip of extreme anxiety and fear. Whatever it was exactly angels or something else, it was not like anything I have ever heard before. They were in the thousands, the voices were more of a vibration of the most beautiful collective choir of song I have ever heard. Whatever it was it helped with the fear during the time tremendously.
I am not sure whether they were angels or not. I was taught by my father that angels are evil. However, this is the same man who told me I was an angel, and evil...sooooooo...
I do not know whether these angels of light exist or not. But I do know what I heard, and it was the most compassionate thing for any being to do. To take the fear of another being away, in an effort to calm.