So if I've understood everything correctly there are 2 types of sounds we're talking about:
1) the sound of the amp/cab somewhere out in the room and
2) the sound of that same amp/cab but 1 inch away.
In situation 1 the unpleasant sounds don't have enough power to reach everyone and so aren't heard.
In situation 2 we then have 2 applications:
A) live situation (mic and then PA)
B ) Helix (impulse response - going either to a recording or to the PA)
In both of these situations we have low and high cuts that have to be applied as they are now part of the signal.
