On Thursday, 10 August 2017 13:22:52 UTC+3, Brian Gaff wrote:

when listening to music in a hall with your ears and then over headphones
from a set of mikes you notice the echo on the latter but not on your ears.

What you are hearing from you "set of mikes" is often not representative of
the acoustic sound in the venue, in many other respects. But it can be. A good example is a classical ensemble recorded with a tree (three omnis, or one omni and two cardioids, with or without outriggers - there are many possible variations) The main mics, (the tree) are set above the conductor's head. During rehearsals, I like to sit at the top of a step ladder, just behind the conductor's rostrum at about the same height as the tree. I listen with wireless headphones (Sennheiser 1200) and am impressed by how close the tree sound (headphones on) is to the acoustic sound (no headphones)

Iain