Useful post. Given that you can take a well mixed/mastered/produced album, play it through a top-end audio system in a flattering acoustic environment, and by messing with the controls make it sound bloody awful, the harm that can be done to the sound of an amateur/semi-pro band playing through a low/mid-price PA in a challenging acoustic environment is obvious. As is always the case, half the battle is having better gear, it's simply knowing how to use the gear you've got 👍