A400 doing a bit of circuit bashing at Bournemouth now.
Can you really hear them when they're at FL300? That's what I call LOUD!
Friend in Worthing had one overfly outbound Brize at around 30000' this morning - he said it was very noisy.
I had a Turkish example overfly me earlier at about 27000' also outbound Brize - the noisy bit is relatively brief as it passes overhead and almost gives the impression of resonance. On occasions it is quite harsh on the ears.
Still rather quieter than the incredible An-22 though which really does rattle one's fillings, even at 30000' plus.