loud vs subsonic

loud

adj
  • Noisy. 

  • High-quality; premium; (by extension) having a strong or pungent odour indicating good quality. 

  • Of great intensity. 

  • Having unpleasantly and tastelessly contrasting colours or patterns; gaudy. 

  • Not subtle or reserved, brash. 

noun
  • High-quality marijuana. 

  • A loud sound or part of a sound. 

adv
  • Loudly. 

subsonic

adj
  • having a frequency too low to be audible 

  • with a Mach number such that 0.3 < Ma < 0.8 (approximately - the exact limits vary between sources) 

  • very quiet, almost inaudible 

  • (aviation) less than the speed of sound (in the same medium, and at the same temperature and pressure) 

noun
  • an aircraft whose maximum speed is less than the speed of sound 

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