baritone vs baritone horn

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 

baritone horn

noun
  • A brass instrument in the baritone range that is similar to a euphonium. 

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