The main problem with hiring a band to play in a small venue comes from the fact that most bands will have a drummer, or in our case, a drummer and lots of other percussion.
Even without mic'ing the drum kit, a common practice to enable tone-shaping, the drums are going to be loud and so it's inevitable that the other instruments need to be louder to be heard above that.
Add to that the vocals, which would neccessarily need to be louder than everything else and you end up with a sound big enough to rattle a few slates loose!!
You can only turn down so far without it turning into a shed-builders convention!

C-flat.