falsetto vs whirr

falsetto

verb
  • To sing or utter in falsetto. 

noun
  • A person who sings in falsetto. 

  • The "false" (singing) voice in any human, usually airy and lacking a purity of vowels; created by utilizing the next highest vocal folds above those used for speech and normal range singing. It is commonly confused with the head voice register. 

whirr

verb
  • To cause (something) to make such a sound. 

  • To make a sibilant buzzing or droning sound. 

  • To move or vibrate (something) with a buzzing sound. 

noun
  • A sibilant buzz or vibration; the sound of something in rapid motion. 

  • A bustle of noise and excitement. 

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