I have never heard a multi Avon except for daily Comet overflights throttled back in the cruise
But it needs the raw difficult to explain sound of a turbojet, or four of them that size.
The early turbofans called by-pass Jet by the British were still noisy unlike the high bypass that followed but they did smooth off the edges of the sound a bit and deepen them.
With the early jet they passed in displays so quiet just a whistle, but when they opened up.......
But they would shriek and whistle rather that whine and hum
So anything that shriek whistled and then removes roof tiles on full power should do it
They did rocket assisted takeoff tests with a Victor B1 from I think Hatfield
Can't remember the name of the strapped on rockets but they might have been called Sceptres or something like that.
They were said to be about the noisiest take off ever in the UK at least.
Perhaps anyone who lived near Hatfield will remember that.
Garry
