Twenty questions continuation

Ok Looks like that subject has exhausted itself.

Here is a new clue.

Abstract. Urban myth says you won't hear this twice. But it is a myth.

bump

I'm here Mr WB - not sure where to begin with this one lol

There is a clue in my post regarding where to start. But you don't seem to have spotted it by the sound of it.

The final trump?

Sonic boom?

OK, you have correctly decided that it is a sound.

A sonic boom -- no
A Trump, now I wish I had thought of that one, but no, however there is a slight similarity.

18 to go

Can't be a gunshot - I believe that if the bullet hits you and kills you, you don't hear the sound once let alone twice.

Brown note?

Can't be The Mating-call of the Racket Tailed Drongo. That is a book.

Can't be lightning striking twice as I don't think it makes any sound at all (certainly nothing trump-like! )

Not sure what a brown note is, but no

The mating call etc etc, you joke, but you are amazingly close.

17 to go

Brown note is a frequency said to make humans lose control of their bowels!

LOL, the circumstances under which I recently hear this sound could have caused me to wet myself.

Birdsong?

Birdsong yes, although song may be pushing it a bit.

16 to go

Cuckoo?

Not Cuckoo
15 to go

Owl?

Owl no
14 to go

Peacock

Corncrake

Duck?

Peacock, Corncrake, no no

12 to go

Think we're losing sight of the urban myth aspect now!