An awful lot has to do with the accoustics of the room. If the soundie is halfway down the hall, then he stands a fair chance of getting a balanced reading. At the back of a long hall he's likely to get distorted (i.e., quieter) reading. If he's on or behind the stage, then there isn't a bat in hell's chance of getting any balance at all. All he will hear is the band projecting outwards towards the people. He won't be able to hear properly so he'll crank up the volume, leading to feedback as the band turn their respective instruments up to counteract the blast of sound coming from the foldback... Then there's the twit who sound checks with one mic turned off..... it happened to me yesterday. Of course, it was the quietest instrument that was penalised....

Same goes for bands - they are on stage, what they hear is not what the audience hears... not unless they have an incredibly good foldback and the stage has the same accoustics (highly unlikely). The Albert Hall was designed for 'unplugged' concerts - amplification in those days meant shouting through a brass cone. Therefore, the accoustics are so good, you could probably manage a set there with no need for any amplification. Trouble is, it would never happen because people are no longer quiet as they used to be and there would be an unending noise of munching, whispering, slurping and shuffling. It's only when they wired the place for sound that the need for the famous ceiling mushrooms arose.

LTS