The GE90-115 on the 77W sounds like a beam engine when starting.....clanking and banging away until it settles down
Perhaps it was because there were 3 (harmonics?), but the RB211's on the Tristar sounded just perfect
This summer, when temporarily back in the UK from my home in SA, the two distinctive noises that always made me look upwards were the haunting banshee wail of the A400M's heading into or out of Brize, high over my house near Bracknell and the earth rumbling drone of An-12's steadily plodding their trade on the airways
It is of course a sign of the times that a pair of Pratts, GE's or Rollers on a modern jet are remarkable only for their quietness, particularly the A350