Sat next to the Port side inlet in a DC9 out of Burbank, California to Las Vegas once. Scarely sounds from those turbines......on startup..the starter motor whine, the flame igniting then sounding like a oxy/ acet flame burning in a strong breeze, every RPM change in flight and the worst was looking out the window on a late curving left turn on to final and seeing (& feeling) we were now undershooting after just flying through a hot desert thermal with the power back near flight idle, then hearing the turbines slowly spool up to full power (Flame sounded like it was going to blow out again!) just before we reached the piano keys! Touch down was heavy then they pulled the power off again!