The Concert "Suck Knob" Syndrome

Awhile ago my friend went to a concert and once again experienced the "Suck Knob", here is what he had to say, as well as my comments on the subject:

Why is it that the sound men for opening acts at a concert aren't allowed to bring the band up to the same or similar standard as the headlining band? Is there a "suck knob" or filter back there that makes them sound that much worse only to make the main act sound that much better? Always been a mystery to me. I can see making the main band sound better but not by making the opening bands sound like a muddy unintelligible mess! Definitely the case with the concert I was at recently. I went to hear David Crowder Band who was opening for Third Day. Despite the suck knob being set to 5 or 6 Crowder didn't disappoint. Sound techs, there's got to be another way to do this!

Now, bout the so called 'Suck Knob', though there are times when a Sound Tech WANTS to use 'it', it doesn't exist. Normally there are a variety of issues that will cause this effect:
1. Though a crew can be efficient and set up for 3-4 bands in 4-6hrs or less, (sometimes more) usually the sound check is focused on the Headliner. So thus sometimes, even though we hate it, the opening bands get the short and quick and everything doesn't get dialed in right.
2. Piggybacking on #1 is the fact that EVERY venue is acoustically UNIQUE, thus setting up and sound checking in an EMPTY venue and the filling it with people is going to drastically change how it sounds and therefore will have to be modified, yes, during the openers! :(
3. Now the previous issues were pure logistics and technicality, this one is personnel, i.e. if you have a crew, and u are letting the rookie mix while you are busy fixing the above issues, or you are having to mix yourself whilst fixing above issues, well your mix is gonna 'SUCK' till you have all the proverbial 'bugs' worked out.

As a Sound Tech, this issue is very familiar to me, the worst part about it is the fact that not only do you, your crew and the audience know that it Sucks it the fact that the band that is having the "Suck Knob" turned up on knows it. As a musician I know that the knowledge that your sound sucks is a huge weight on your shoulders (i.e. having the frustration and still trying to still put on a great show).
Though on the other side of the coin, there are times when the band is stressed out about getting ready for the show that during sound check the band can be very testy and want to have it setup and dialed in right now and are unwilling to take the time to let the Tech get it dialed in correctly...