then there are the guys that run sound in churches.  ...almost to the point of total distraction and the people in the booth have their face buried in their phone.  ;-/

mettelus
Unfortunately the "loud is better" crowd has made themselves so deaf they have become the "if it is not loud, I hear nothing" crowd. Self-fulfilling prophecy but incredibly sad since most industries enforce hearing protection except for the one that should the most (you can be deaf as a post and still drive a jackhammer).

In the UK the Health and Safety Executive (and local authorities in the categories of businesses where the function is devolved from HSE to them) enforce similar hearing protection on events, clubs, venues and studios that they do in any workplace. Not on the punters (so long as they're warned in advance it's going to be loud they are left to care for themselves) but for the staff, including stage crew and engineers, who are there as workers. Also advice for musicians (including orchestral, lots of orchestral musicians get hearing damage).

There's even a dedicated website - http://soundadvice.info

Jeff Evans
The other problem is most live mixers have no musical knowledge either.  In one of these posts it was mentioned no guitar was present out front.  I would heard that in a microsecond and gone looking for the problem.  Because one should look up see what is supposed to be there but some live guys just cannot do that for some reason.

 
If the "engineer" had glanced down he would have found it. Or at least should have. The desk was at the back of the auditorium, about 800 capacity. Had a look on the way out, it was an everyday 24-track or so analogue Soundcraft.

Now, call me paranoid but I've always thought it a good idea to take a glance across the desk when a new band comes on following a change-over to make sure the channel indicators, whether meters or just a single LED, are showing there's something coming in on the channels where audio is expected and nothing on the ones where it isn't. Then double check the mutes and solos. Even better do a quick line-check during the change-overs.

No such caution for our hero though it seems. When he finally realised something was badly wrong the first thing that happened was a stage hand walked on and shifted the amp mic, an SM57 by the look of it, a few inches. No change. OK, switch the cable to the stage-box. No change. Lengthy pause for head-scratching. OK, engineer goes on stage and fiddles around with the mic and cable for a bit. Taps mic. Takes it out of clip and - queue fanfare - turns it on. Instant howl so turns it off...

Eventually sorted after an unscheduled 10 minute plus "interval".

Jeff Evans
Another problem too is when someone takes a solo most live mixers cannot hear that and they end up just at the same too low volume.  I move that person to the centre and turn them up to bring out the solo and then when finished moved them back and turn them down a little.  That is something from my Jazz days I suppose.
 

People with the ability and musical feel to get sound right are out there, and there's a lot of them. But, as you say, there are also quite a number who are in completely the wrong profession and sound engineering can make or break a gig.

From a musician's point of view the problem isn't just bad sound during the gig. If the sound is rubbish the punters tend not to think "really good band sadly let down by poor sound engineering, not their fault" but "rubbish/boring band".

I saw a Genesis tribute band in a small venue. They were pretty good but the guy on the mixing desk was apparently unfamiliar with the material and ruined some otherwise good moments. He was prone to turning up the guitar every time the guitarist looked as though he was was about to do something interesting, unaware that the guitar parts were meant to be mostly supportive and counterpointing to the keyboard parts. I went to see them again a year later. Same venue, same guy mixing, no improvement.
 

Saw Lenny Kravitz play once, didn't hear him. I heard him sing, I heard the band, I saw him play, but couldn't hear him. Whole gig, nothing. I think it was the last Glastonbury I went to about  15 years ago.
 
Been to a lot of festivals with a great sound. Not normally the main stages though.
 

Jeff Evans
Live mixing is an industry that seems to have attracted many people who are just plain useless and have no ears at all.  There does not seem to be any consistency or regulation in it for some reason.

This is very true.... but I do find regions where good sounds techs are abundant. I am lucky to live in such a region. Winnipeg is head office to one of the largest sound company's in Canada and some of the finest techs in the industry. Fly by night techs are not tolerated by the artists here.... if you are not a good tech, you do not get hired. The other company's (independent, small or large) raise their standards to compete... and techs essentially "apprentice" under good/great techs before heading out on their own.
 
I read threads all the time about bad sound techs and a complete lack of trust in them. Yes - I have witnessed that in my travels, but rarely encounter it locally.
 
 

I've also witnessed intentional sabotage. Usually, it's the headliner making sure the opening act sounds worse.

Kamikaze
Saw Lenny Kravitz play once, didn't hear him. I heard him sing, I heard the band, I saw him play, but couldn't hear him. Whole gig, nothing. I think it was the last Glastonbury I went to about  15 years ago.

From 2014...why I don't go to Glastonbury any more.
 

bitflipper
That was not the case. It was a flown array, but it was the band's own gear and their own FOH guy. And he was an old guy! Old as me. Old enough you'd assume he had a lot of experience.
 
Or perhaps old enough that he just didn't give a sh*t anymore.

The Old guy probably has the same issue I do.  Lack of mid range hearing.  Too many concerts/gigs with sound too loud.  I don't trust my ears any more for live sound, but get a general consensus when I do it.  I also rely a lot on my DriveRack for initial settings.
 
 

I won't make excuses for the Old Guy. 30 years of live mixing probably has degraded his hearing, but surely he knows about spectrum analyzers.
 
They've had some pretty sophisticated auto-EQ systems for many years, too. Heck, I was using an RTA for PAs back in the 80s because I didn't have the luxury of a sound guy to make corrections on the fly. It wasn't ideal, but at least I could avoid the icepick-to-the-ear syndrome.