Spotify or Pandora

A relative pointed out two music download websites: Spotify and Pandora. I don't know anything about music downloads. But I was hoping to stream hi-rez original artist oldies. I tried one selection on Spotify and it sounded like MP3 quality and didn't seem like original artists were singing.

Please advise. I would love to stream in hi-rez oldies from the 50s and 60s, but don't know if Spotify or Pandora are good sources.

Thanks