aftersound vs repercussion

aftersound

noun
  • A sound that persists or remains audible after its source has ceased to produce it; the perception of such a sound. 

  • The second, slower phase of decay in the sound made by a piano string when it is struck. 

repercussion

noun
  • Rapid reiteration of the same sound. 

  • In a vaginal examination, the act of imparting through the uterine wall with the finger a shock to the foetus, so that it bounds upward, and falls back again against the examining finger. 

  • The subsidence of a tumour or eruption by the action of a repellent. 

  • The act of driving back, or the state of being driven back; reflection; reverberation. 

  • A consequence or ensuing result of some action. 

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