baritone vs low-toned

baritone

noun
  • a brass instrument similar to the euphonium, but with a cylindrical bore instead of a conical one; a baritone saxhorn 

  • The musical range between tenor and bass 

  • The male voice between tenor and bass 

  • A person, instrument, or group that performs in the range between tenor and bass 

low-toned

How often have the words baritone and low-toned occurred in a corpus of books? (source: Google Ngram Viewer )